Anatomy of colon

Colorectal malignancy and its

management current practices and
recent advances in management
Presentor: Dr Satish H T
Moderator: Dr Chandrakanth Kesari
ANATOMY OF COLON
• The large intestine is a muscular tube which
extends from the end of the ileum to the
anus, and it comprises of caecum and
appendix, colon, rectum and anal canal.
• Its 1.5 metres long.
• It is wider in caliber than the small intestine,
which is greatest at its commencement and
gradually decreases towards rectum.
• The greater part of colon is fixed, except the
appendix, the transverse colon and sigmoid
colon.
• The longitudinal muscle coat forms only a thin
layer in this part of the gut.
• Major part of it forms three ribbon like bands,
called taenia coli( TAENIA LIBERA, TAENIA
MESOCOLICA, TAENIA OMENTALIS).
• Since the taenia are shorter than the cicular
muscle coat, the colon is puckered and
sacculated.
• Small bags of peritoneum filled with fat are
appendices epiploicae which are scattered
over the surface of large intestine, except for
appendix, caecum and rectum.
• CAECUM-
It is a large blind sac forming the
commencement of the large intestine.
Situated in the right iliac fossa.
Communicates superiorly with the ascending
colon, medially with ileum, and postero-
medially with the appendix.
Anteriorly related to coils of intestine and
anterior abdominal wall.
• Posteriorly to right psoas and iliacus.
• Genitofemoral , femoral and lateral cutaneous
nerve of thigh.
• Testicular vessels or ovarian vessels.
types of caecum
1. Conical (13%)
2. Intermediate type(9%)
3. Ampullary type(78%)
• Vermiform appendix-
Worm like diverticulum arising from the
posteromedial wall of the caecum about 2cm
below the ileocaecal orifice.
It varies in length from 2 to 20cm with an
average of 9cm. The diameter is about 5mm.
The appendicular orifice is occasionally guarded
by an indistinct semilunar fold of mucous
membrane, known as valve of Gerlacti.
• The appendix is suspended by a small,
triangular fold of peritoneum, called the
mesoappendix. The fold passes behind the
ileum and it is attached to the left layer of
mesentry.
• The Colon is divided into four parts: the
ascending, transverse, descending, and
sigmoid.
• The Ascending Colon (colon ascendens) is
smaller in caliber than the cecum, with which it
is continuous.
• It passes upward, from its commencement at the
cecum, opposite the colic valve, to the under
surface of the right lobe of the liver, on the right
of the gall-bladder, where it is lodged in a shallow
depression, the colic impression; here it bends
abruptly forward and to the left, forming the
right colic (hepatic flexure).
• It is retained in contact with the posterior
wall of the abdomen by the peritoneum,
which covers its anterior surface and sides, its
posterior surface being connected by loose
areolar tissue with the Iliacus,Quadratus
lumborum, aponeurotic origin of Transversus
abdominis, and with the front of the lower
andlateral part of the right kidney.
• The Transverse Colon (colon transversum) the
longest and most movable part of the colon,
passes with a downward convexity from the
right hypochondriac region across the
abdomen, into the left hypochondriac region,
where it curves sharply on itself beneath the
lower end of the spleen, forming the left colic
(splenic) flexure.
• It is almost completely invested by peritoneum, and is
connected to the inferior border of the pancreas by the
transverse mesocolon.
• It is in relation, by its upper surface, with the liver and
gall-bladder, the greater curvature of the stomach, and
the lower end of the spleen; by its under surface, with
the small intestine; by its anterior surface, with the
anterior layers of the greater omentum and the
abdominal parietes; its posterior surface is in relation
from right to left with the descending portion of the
duodenum, the head of the pancreas, and some of the
convolutions of the jejunum and ileum.
• The left colic or splenic flexure is situated at the
junction of the transverse and descending parts of the
colon, and is in relation with the lower end of the
spleen and the tail of the pancreas; the flexure is so
acute that the end of the transverse colon usually lies
in contact with the front of the descending colon.
• It lies at a higher level than, and on a plane posterior
to, the right colic flexure, and is attached to the
diaphragm, opposite the tenth and eleventh ribs, by a
peritoneal fold, named the phrenicocolic ligament,
which assists in supporting the lower end of the
spleen.
• The Descending Colon (colon descendens) passes
downward through the left hypochondriac and lumbar
regions along the lateral border of the left kidney. At the
lower end of the kidney it turns medialward toward the
lateral border of the Psoas, and then descends, to end in
the sigmoid colon. The peritoneum covers its anterior
surface and sides, while its posterior surface is connected
by areolar tissue with the lower and lateral part of the left
kidney, the aponeurotic origin of the Transversus
abdominis, and the Quadratus lumborum.
• It is smaller in caliber and more deeply placed than the
ascending colon, and is more frequently covered with
peritoneum on its posterior surface than the ascending
colon . In front of it are some coils of small intestine.
• Sigmoid colon-
It is about 37.5cm long and extends from the
pelvic brim to the third piece of sacrum,
where it becomes rectum.
It forms a sinuous loop, and hangs down in the
pelvis over the bladder and the uterus.
It is suspended by the sigmoid mesocolon and is
covered by the coils of small intestine.
• RECTUM
It is the distal part of the large gut. Placed between
the sigmoid colon above and the anal canal
below.
Situated in the posterior part of the lesser pelvis,
infront of the lower three pieces of sacrum and
the coccyx.
it measures 12cm long, upper part has same
diameter as that of sigmoid colon but the lower
part is dilated to form the rectal ampulla.
• Rectum first runs downwards and backwards,
then downwards, finally downwards and
forwards.
• Two anteroposterior curves- the sacral flexure
The permeal flexure.
• Three lateral curves- upper, middle and lower
lateral curves.
• Peritoneal relations-
Upper one third is covered with peritoneum infront
and on the sides, middle one third only in the
front, lower one third is devoid of peritoneum.
• Visceral relations-
In males- anteriorly, upper 2/3rd is related to
rectovesical pouch with coils of intestine and
sigmoid colon.
Lower 1/3rd of the rectum is related to the base of
the urinary bladder, the terminal parts of ureters,
seminal vesicals, ductus deferens, prostate.
• In females-
Upper two thirds is related to the recto-uterine
pouch with coils of intestine and sigmoid
colon.
Lower one third of rectum is related to lower
part of vagina.
• Posteriorly- lower three pieces of sacrum,
coccyx and the anococcygeal ligament.
• Pyriformis, coccygeus and levator ani
• Anal canal-
Terminal part of the large intestine.
Situated below the pelvic diaphragm.
Lies in the anal triangle of the perineum in
between right and left ischiorectal fossae.
It is 3.8cm long, extends from the anorectal
junction to the anus. It is directed
doownwards and backwards.
• Relations-
Anteriorly- perineal body,
Membranous urethra and bulb of penis in males. Lower
end of vagina in females.
Posteriorly- anococcygeal ligament.
Laterally- ischiorectal fossa
• Interior of the anal canal-
Upper 15mm- lined by mucous membrane, endodermal
in origin.
Mucous membrane has vertical folds- anal columns of
morgagni.
• Next 15mm is also lined by mucous
membrane. It is known as the pecten or the
tansitional zone.
• Lower limit of this is the white line of hilton.
• Lower cutaneous part which is 8mm
containing sweat and sebaceous glands.
 BLOOD SUPPLY
• The arteries supplying the colon are derived
from the colic and sigmoid branches of the
mesenteric arteries. They give off large
branches, which ramify between and supply
the muscular coats,and after dividing into
small vessels in the submucous tissue, pass to
the mucous membrane.
• The rectum is supplied by the superior
hemorrhoidal branch of the inferior
mesenteric, and the anal canal by the middle
hemorrhoidal from the hypogastric, and the
inferior hemorrhoidal from the internal
pudendal artery.
• The superior hemorrhoidal A, the continuation of
the inferior mesenteric, divides into two
branches, which run down either side of the
rectum to within about 12.5 cm. of the anus; they
here split up into about six branches which pierce
the muscular coat and descend between it and
the mucous membrane in a longitudinal
direction, parallel with each other as far as the
Sphincter ani internus, where they anastomose
with the other hemorrhoidal arteries and form a
series of loops around the anus.
• The veins of the rectum commence in a plexus of vessels
which surrounds the anal canal.
• In the vessels forming this plexus are smaller saccular
dilatations just within the margin of the anus; from the
plexus about six vessels of considerable size are given off.
• These ascend between the muscular and mucous coats for
about 12.5 cm., running parallel to each other; they then
pierce the muscular coat, and, by their union, form a single
trunk, the superior hemorrhoidal vein. This arrangement is
termed the hemorrhoidal plexus; it communicates with the
tributaries of the middle and inferior hemorrhoidal veins, at
its commencement, and thus a communication is
established between the systemic and portal circulations.
 lymphatics
• Lymph from the large intestine passes through
four sets of nodes-
• Epiploic lymph nodes- lying on the ic wall of the
gut.
• Paracolic nodes- on the medial side of ascending
and descending colon.
• Intermediate nodes- on main branches of the
vessels
• Terminal nodes- on superior and inferior
mesenteric vessels.
 Nerve supply
• The midgut territory receives the sympathetic
supply from from the coeliac and the superior
mesentric ganglia, parasympathetic supply
from the vagus.
• The hindgut territory receives its sympathetic
supply from the supply from the pelvic
splanchnic nerves both via superior
hypogastric and inferior mesenteric plexus.
Colorectal malignany and its
management
current practices and recent
advances in management
 Epidemiology

• Adenocrcinoma of colon and rectum is the third

most common site of new cancer cases and
deaths in men and women in united states.
• In UK it is the second most common cause of
cancer death.Approximately 35,000 patients are
diagnosed with colorectal cancer every year
• Colorectal cancer occurs less frequently in the
resorce poor world than in resorce rich countries
• Recent trend is decreased in the incidence of
cancer in people more than 50 years of age
compared to those less than 50 years.
• Hence in 2018, ACS has recommended
reducing the age for colorectal cancer
screening down to 45 years.
• Increase in the incidence of right colon cancer.
 Aeitiology

• The accepted model of colorectal cancer

developmentb is that it arises from
adenomatous polyps after sequence of
genetic mutations influenced by
environmental factors.
• Colonic cancers may be
• Nonhereditary colon cancer
Sporadic -60%
Familial – 30%
• Hereditary colon cancer
FAP
HNPCC
Peutz jeghers syndrome
Cronkite canada syndrome
Juvenile polyposis syndrome
• Worldwide, the prevalence of colorectal cancer is closely
associated with intake of red meat and particularly
processed meat products (haem and N-nitroso
compounds). These adversely affect DNA in the colorectal
mucosa. A protective effect of dietary fibre is also
suggested by epidemiological studies. The hypothesis is
that increased roughage is associated with reduced colonic
transit times, and this in turn reduces the exposure of the
mucosa to dietary carcinogens. Increased risk for colorectal
cancer has also been associated with dietary animal fat,
smoking and alcohol. Cholecystectomy may marginally
increase the risk of rightsided colon cancer and
inflammatory bowel disease is a well-recognized risk factor.
 Pathology

• Most large bowel cancers arise from the left

colon, notably the rectum (38%), sigmoid
(21%), and descending colon (4%). Cancer of
the caecum (12%) and ascending colon (5%)
are less common, but may be gradually
increasing in incidence. Cancer of the
transverse colon (5.5%), flexures (2–3%) and
appendix (0.5%) are relatively uncommon.
• Gross types :
• Annular- more common on left side. Here the
growth spreads round the intestinal wall and
so it often presents with intestinal obstruction
• Ulcerative – common on right side
• Proloferative – common in right side . It is
fleshy ,bulky,and polypoidal .
• Histological types :
• Adenocarcinoma 90%
• Mucinous adenocarcinoma 5-10%
• Signet ring cell carcinoma
• Small cell/oat cell carcinoma
• SCC
• Undifferentiated carcinoma
 Spread
Colonic cancer can spread locally or via the lymphatics, bloodstream or
transcoelomically across the peritoneal cavity. Direct spread may be
longitudinal or radial. Radial spread may be retroperitoneal into the ureter,
duodenum and posterior abdominal wall muscles or intraperitoneal into
adjacent organs or the anterior abdominal wall. In general, involvement of
the lymph nodes by the tumour progresses from those closest to the
bowel along the course of lymphatics to central nodes. However, this
orderly process does not always occur. Haematogenous spread is most
commonly to the liver via the portal vein. One-third of patients will have
liver metastases at the time of diagnosis and 50% will develop them at
some point, accounting for the majority of deaths. The lung is the next
most common site; metastasis to ovary, brain, kidney and bone is less
common. Colorectal cancer can spread from the serosa of the bowel or via
subperitoneal lymphatics to other structures within the peritoneal
cavity, including peritoneum, ovary and omentum.
 Clinical features

• Commonly present with loss of appetite and

weight , abdominal discomfort and mass per
abdomen.
• 20% of cases present as an acute intestinal
obstruction
• 20% of colonic/colorectal cancer has stage IV
disease at the time of first presentation.
• Right sided growth
• Commonly presents with anaemia, palpable
mass in RIF,
• Carcinoma caecum occasionally presents like
acute appendicitis or intussusception with
intestinal obstruction.
• Left sided growth:
• Presents with colicky pain,altered bowel
habits ,palpable lump,distention of abdomen
due to subacute / chronic obstruction . Later
may presents like compltete colonic
obsrtruction. Tenesmus ,with passage of blood
and mucus,with alternate constipation and
diarrhoea.
• Enlarged liver with multiple umilicated hard
secondaries,ascitis,rectovescical
secondaries,palpable left supraclavicular
lymph nodes etc..
 Investigations
• RADIOLOGY
• Double-contrast barium enema has traditionally
been used and shows a cancer of the colon as a
constant irregular filling defect, often described
as looking like an apple-core . False positives
occur in 1–2% of cases and false negatives in 7–
9% of cases. It has now been largely replaced by
computed tomography (CT) virtual colonoscopy,
which is extremely sensitive in picking up polyps
down to a size of 6 mm
. It has the advantage of being less Invasive than
colonoscopy but if a biopsy is required, an
endoscopy will still be needed. CT is used as a
diagnostic tool in patients with palpable abdominal
masses. Spiral CT of the chest, abdomen and pelvis
now represents the standard means of staging
colorectal cancer, although chest x-ray and liver
ultrasound are alternatives if CT is not readily
available. Rectal cancer usually requires additional
staging for local spread, using magnetic resonance
imaging.
 Endoscopy

• The 60-cm, fibreoptic, flexible sigmoidoscope

is increasingly being used in ‘one-stop’ rectal
bleeding clinics. The patient is prepared with
an enema and sedation is not usually
necessary. It is usually possible to assess the
bowel up to the splenic flexure, which will
detect up to 70% of cancers and almost all
that cause fresh rectal bleeding . Colonoscopy
is the investigation of choice if colorectal
cancer is suspected,
• provided the patient is fit enough to undergo
the mechanical bowel preparation required. It
has the advantage of not only picking up a
primary cancer but also having the ability to
detect synchronous polyps or other
carcinomas, which occur in 3–5% of cases.
There is a small risk of perforation (1:1000).
• CEA:It is a cell surface glycoprotein discovered by Gold and
FreedmanIt is normally produced by colonic epithelium. Its
serum ½ life is up to 10 days and is cleared by liver through
Kupffer cells. So its ½ life prolongs in cholestasis and
hepatocellular dysfunction.
• Normal level is <2.5 ng/ml. Level >5 ng/ml is significant.
• Even though it is a widely used tumour marker, it has
• got low sensitivity.
• CEA is primarily associated with colorectal cancers, but
• it can also increase significantly in pancreatic, gastric, lung,
breast carcinomas. Often its level also increases in
nonmalignant conditions like pancreatitis, hepatitis,
obstructive jaundice, BPH.
• Uses in colorectal cancers are:
• a. Preoperative levels >7.5 ng/ml signifies
poor prognosis.
• b. If postoperative level does not fall, it
indicates either incomplete resection, or
occult metastasis elsewhere.
• c. Increase CEA during follow-up indicates
recurrence or secondaries.
• A slow rise indicates loco regional disease.
• A rapid rise signifies metastasis.
• It is not useful in assessing follow-up in poorly
differentiated adenocarcinoma as such
tumour will not produce CEA.
 Management
SURGICAL:
• PREOPERATIVE PREPARATION
• Mechanical bowel preparation has fallen out of favour
in surgery for colon cancer, with little evidence of
benefit and some of an increased rate of wound
infection. It currently remains in use largely for low
rectal resection, where unprepared bowel may be
associated with a higher infection rate. Antiembolism
stockings should be fitted and the patient started on
prophylactic subcutaneous low molecular weight
heparin. If available, manual compression boots are
used perioperatively
Intravenous prophylactic antibiotics are given
immediately before the start of surgery, to
reduce the risk of surgical site infection. A single
dose of antibiotics covering bowel organisms is
as effective as multiple doses. In all cases where
a stoma seems likely, careful preoperative
counselling and marking of an appropriate site
by an enterostomal therapist is essential.
 OPERATIONS
• The operations described are designed to remove the
primary tumour and its draining locoregional lymph nodes.
It is unusual to find unsuspected metastases at laparotomy
(or laparoscopy) after CT staging, but the presence of
peritoneal metastases may predicate a palliative strategy
with a segmental resection and less aggressive
lymphadenectomy. The use of stapling and hand-suturing
techniques for colonic anastomoses have been compared,
and there is probably little difference in leak rate. It is more
important that healthy bowel, free of tension or distal
obstruction, is used to construct an anastomosis and that
patients are adequately nourished and free from active
infection if anastomotic leakage is to be avoided.
 Right hemicolectomy
• Carcinoma of the caecum or ascending colon is treated
by right hemicolectomy . At open surgery the
peritoneum lateral to the ascending colon is incised,
and the incision is carried around the hepatic flexure.
The right colon and mesentery are elevated, taking
care not to injure the ureter, gonadal vessels or the
duodenum. The ileocolic artery is ligated close to its
origin from the superior mesenteric artery (‘high-tie’)
and divided. Where the right colic artery has a separate
origin from the superior mesenteric artery (around
10% of patients) this is separately ligated.
 The mesentery of the distal 20 cm of ileum and the
mesocolon as far as the proximal third of the
transverse colon is divided. The greater omentum is
divided up to the point of intended division of the
transverse colon. When it is clear that there is an
adequate blood supply at the resection margins,
the right colon is resected, and an anastomosis is
fashioned between the ileum and the transverse
colon. If the tumour is at the hepatic flexure the
resection must be extended further along the
transverse colon and will involve dividing the right
branch of the middle colic artery.
 Extended right hemicolectomy
• Carcinomas of the transverse colon and splenic
flexure are most commonly treated by an
extended right hemicolectomy. The extent of the
resection is from the right colon to the
descending colon. The mobilisation is as for a
right hemicolectomy but dissection continues to
take down the splenic flexure and the whole
transverse mesocolon is ligated. Some surgeons
prefer to perform a left hemicolectomy for a
splenic flexure cancer.
 Left hemicolectomy
• This is the operation of choice for descending
colon and sigmoid cancers . The left half of the
colon is mobilised completely along the ‘white
line’ that marks the lateral attachment of the
mesocolon. As the sigmoid mesentery is
mobilised, the left ureter and gonadal vessels
must be identified and protected. The splenic
flexure may be mobilised by extending the
lateral dissection from below and completed
by entering the lesser sac
• The inferior mesenteric artery below its left colic
branch, together with the related paracolic lymph
nodes, is included in the resection by ligating the
inferior mesenteric artery close to its origin (‘high-tie’).
For full mobility the inferior mesenteric vein is also
ligated and divided at the lower border of the
pancreas. The bowel and mesentery can then be
resected to allow a tension-free anastomosis. A
temporary diverting stoma may be fashioned
upstream, usually by formation of a loop ileostomy.
This is usually undertaken if the anastomosis is below
the peritoneal reflection of the rectum, because
healing ismore likely to be impaired distally.
 Laparoscopic surgery
• Laparoscopic surgery for colon cancer has
been shown to have equivalent overall and
cancerrelated outcomes to open surgery.
Lymph node harvests are equivalent to open
surgery and initial concerns about reports of
port site recurrence have been dispelled
Operation times are longer but wound
infection rates, blood loss and postoperative
pain scores are lower than for open surgery
• It is not possible to palpate lesions, so if
laparoscopic surgeryi s planned it is useful to
tattoo the lesion at prior colonoscopy. The
laparoscopic operation has particular advantages
if performed in a medial to lateral manner – that
is starting the dissection by controlling and
dividing the major vascular pedicles and only
taking the lateral peritoneal reflection once the
mesocolon is completely free. Specimen retrieval
and bowel anastomosis can then be performed
via small incisions.
 Emergency surgery
• 20% of patients with colonic cancer will present
as an emergency, the majority with obstruction,
but occasionally with haemorrhage or
perforation. If the lesion is right sided, it is usually
possible to perform a right hemicolectomy and
anastomosis in the usual manner. If there has
been perforation with substantial contamination
or if the patient is unstable, it may be advisable
to bring out an ileocolostomy rather than forming
an anastomosis.
• For a left-sided lesion the decision lies between a
Hartmann’s procedure or resection and anastomosis.
Where endoscopic and radiological facilities are
present an obstructing left-sided lesion can be treated
with an expanding metal stent . This has the advantage
of converting an emergency operation with a high
chance of a stoma to a situation that can be managed
semi-electively by resection and anastomosis. Although
early studies cast doubt on the benefits of colorectal
stenting, more recently evidence has emerged that
stenting leads to a reduction in stoma rates.
 Treatment and Follow-up
Although the prognosis can be refined by careful
and accurate pathologic staging, patients treated
with appropriate resection for stage I colon cancer
generally have a 5-year survival rate of
approximately 90%. The 5-year survival rate for
patients with stage II colon cancer treated surgically
is approximately 75%. The survival of patients with
stage III disease, with lymph node metastasis, is
approximately 50%; and patients with stage IV
disease (distantmetastases) have a poor prognosis,
with a 5-year survival of less than 5%.
Further treatment and follow-up of patients treated by segmental
colectomy for colon cancer is directed by the stage of the
disease. Approximately 85% of recurrences are detected within 2
years of the time of resection, so the follow-up strategy should be
especially intensive during that period.
A reasonable strategy to observe patients with stage I colon
cancer is a colonoscopic examination 1 year after the operation
to inspect the anastomosis but also to detect any new or missed
polyps. The colonoscopy should be repeated annually if any
polyps are detected and removed, until an examination reveals
the absence of polyps. Then, a colonoscopy should be offered
every 5 years unless a strong family history or other genetic risk
factor is present, in which case more frequent endoscopic examinations
are obviously indicated. A CEA level should be determined
every 3 months during the first 2 years, even if the
preoperative CEA level was normal
 A rising CEA level requires further tests to search for metastatic disease,
including a CT scan (or MRI) of the abdomen and chest and possibly a PET
scan The goal of close follow-up testing is to detect early recurrence
that is amenable to treatment. Isolated hepatic or pulmonary metastases
are amenable to resection, with a 5-year survival rate of 20%. Multiple or
unresectable metastases may respond to current chemotherapeutic agents.

Postoperative treatment of patients with stage II colon cancer is somewhat

controversial. An attempt to stratify patients may identify a subset that
would benefit from chemotherapy. The 5-year survival rate of patients with
stage IIA disease is 85%, compared with 72% for stage IIB disease, which is
actually worse than for patients with node-positive stage IIIA disease. The
American Society of Clinical Oncology suggests a course of 5-fluorouracil (5-
FU)–based adjuvant chemotherapy for stage II patients with at least one
poor prognostic indicator, including insufficient lymph node sampling (<12
nodes resected with the specimen), T4 lesions, poorly differentiated
histology, or bowel perforation.
Whether oxaliplatin-based regimens should be used in stage II disease in
addition to 5-FU–leucovorin is controversial, but current practice in most
areas appears to favor the addition of oxaliplatin in early-stage disease.
Further follow-up of stage II patients includes a CEA level every 3 months for
2 years, then every 6 months for a total of 5 years, and annual CT scans of
the abdomen and chest for at least the first 3 years.
Patients with stage III disease clearly benefit from adjuvant chemotherapy.
The addition of oxaliplatin to the 5-FU–leucovorinregimen (FOLFOX) has
resulted in an improvement of disease-free survival rates at 3 years to 78%
(compared with 73% with 5-FU–leucovorin alone). Irinotecan (Camptosar)
has been investigated as an addition to 5-FU–based therapy in the adjuvant
setting on the basis of its benefit against metastatic disease. Unfortunately,
irinotecan has not demonstrated efficacy in the adjuvant setting and is not
currently used for the treatment of patients with stage III disease.
The method of delivery of chemotherapeutic agents is evolving.Continuous
infusion of 5-FU is now generally considered to be superior to bolus infusions,
with less toxicity. An oral fluoropyrimidine, capecitabine (Xeloda), has been
shown to be at least equivalent to 5-FU.

The treatment of patients with stage IV disease depends on the location and
extent of the metastases. In general, for asymptomatic patients with stage IV
disease, a chemotherapy first approach is often used. It allows the patient to
benefit immediately from systemic therapy without a waiting period for healing
after surgery. Most patients with asymptomatic stage IV disease do not benefit
from removal of the primary lesion. Removal is not associated with long-term
benefits. However, there are many situations in which metastasectomy is
associated with reasonable long-term survival, with approximately 15% to 24%
of patients surviving at 5 years. Hepatic or pulmonary lesions may be amenable
to resection, typically after three to six cycles of chemotherapy and then
reimaging to determine response.
Good responders with resectable disease may have survival
rates approaching 25% at 5 years. Agents complementing the
5-FU regimens that remain the keystone of therapy are
effective for metastatic disease and are being studied in the
adjuvant setting. These are the monoclonal antibodies
bevacizumab (Avastin), cetuximab (Erbitux), and
panitumumab (Vectibix). Cetuximab is a chimeric (mouse-
human) monoclonal antibody; panitumumab, a fully human
monoclonal antibody, binds to and inhibits the EGFR, which is
overexpressed in 60% to 80% of colorectal cancers and is
associated with a shorter survival time. Cetuximab and
panitumumab are effective only on tumors that do not have a
mutation of the KRAS gene.32 Accordingly, genetic testing is
now recommended to confirm the absence of KRAS
mutations (indicating the presence of the KRAS wild-type
gene) before the use of these EGFR inhibitors is
recommended.
These agents have shown clinical efficacy in patients with
metastatic colorectal cancer, both as monotherapy and in
combination with irinotecan and FOLFOX. Bevacizumab, a
vascular endothelial growth factor inhibitor, has also
improved survival when added to regimens that include
irinotecan, 5-FU– leucovorin, or oxaliplatin.
Changing trends, recent advances and
current practices
• Preoperative investigations :
• Colonoscopy vs computed tomography colonography
• Colonoscopy is preferred investigation for diagnosis of
colon cancer since it permits direct visualization of the
tumour , detect synchronous lesions, facilitates
removal of polyps and allows biopsy from the tumour.
• Currently , ct colonography is primarily indicated in
patients with incomplete colonoscopy due to
nonobstructive cause. CT colonography cannot replace
incomplete colonoscopy in patients with obstructed
left colon cancer as both procedures requires bowel
preperation .
• CT of chest in colon cancer :
• CECT abd and pelvis is primary investigation for staging
in patients with colon cancer . CT is more sensitive to
detect distant spread than regional lymph node
metastasis or depth of tumour infiltration
• Lung metastasis was detected in only 6.3% of patients
without liver metastasis and a negative chest x-ray.
• Based on current evidences routine CT chest is not
recommended in colon cancer patients with no liver
mets and is selectively indicated in patients with
advanced T and N stage tumour.
• PET CT :
• NCCN recommends that PET CT should be
performed before planned curative resection for
liver mets.PET CT is also used in the
postoperative survieillance of patients with rising
serum CEA level and non diagnostic conventional
imaging evaluation following primary treatment
and in detecting synchronus tumours in patients
with obstructed left colon cancer.
 Preoperative management
• Mechanical bowel preperation
• Based on meta analysis published in 2018
concluded that oral antibiotic prophylaxis , in
combination with mechanical bowel
preperation and parenteral antibiotics ,is
superior to mechanical bowel preperation and
parenteral antibiotic prophylaxis alone in
reducing SSI in elective colorectal surgery.
• Preoperative fasting:
• Current ERAS society guidelines are clear
fluids should be allowed upto 2 hrs and solids
upto 6hrs before induction of
anesthesia.specific safety measures should be
taken at the time of induction of anesthesia in
whom gasric emptying may be delayed.
• Prophylaxis against DVT
• Mechanical prophylaxis with compression
stockings and intermittent pneumatic
compression device is strongly
recommended.pharmacological prophylaxis
with LMWH should be given to these patients.
 Surgery for colon cancer

• Optimal colonic cancer surgery:

• Complete mesocolic excision :
• Is to identify the distinct plane between the mesocolic fascia and
retroperitoneal fascia by sharp dissection . This plane is marked by a
single layer of fascia (toldt’s fascia). A good CME prevents the
breach in mesocolic fascia and the potential tumour spread.
• Second important component is to identify and ligate the feeding
arteries at the origin to ensure maximal harvest of regional lymph
nodes.
• Third component of CME is a dissection of pericolic lymph nodes at
least 10cm on either side of tumour as lymphatic spread is rarely
seen beyond 10cm.
• This this technique ensures the integrity of mesocolon and
improves lymph node yield and there by survival in colon cancer.
• D3 dissection:
• The japanese society of cancer of the colon and rectum
recommends D2 lymph node dissection for tumours
restricted to submucosa and D3 lymph node dissection for
tumour reaching muscularis propria or in patients with
clinical evidence of lymph node metastasis irrespective of
depth of invasion.
• For the right colon cancer in D2 dissection , the ileiocoloic
vessels are tied to the rightof SMV without removing the
lympho adipose tissue over the SMV
• Whereas in D3 dissection for right colon cancer ,the
ileocolic vessels are divided at the origin after clearing the
lympho adipose tissue over theSMV and exposing them.
• CME with CVL versus D3 dissection
• The no of mesenteric nodes removed is more
in CME with CVL compared to D3 dissection .
• Both CME with CVL and D3 dissection result in
comparible oncological specimens and
outcomes that are superior to conventional
colon surgeries .
 Management of obstructed colonic
cancer
• Stoma creation or ileotranseverse bypass is
reserved for patients with unresectable
tumours .
• Percutaneous cecostomy is an option in poor
risk patients although it is often associated
with inadequate decompression.SEMS as a
bridge to elective surgery is not recommended
for obstructed right colon cancers,it is also an
option in the palliative settings.
 Approach to the patients with the
metastatic disease
• All patients with metastatic colon cancer
should undergo genetic testing including K-ras
,neuroblastoma RAS and B raf mutations.
• The management of metastatic colon cancer
primarily depends on three factors viz. the
resectability of the primary colonic tumor,
resectability of the extracolonic organ
metastasis and the presence of potentially
“convertible to resectable” secondaries.
• Three types of management protocols with
respect to timimg of the resectionof lung/liver
metastasis.
• 1. concurrent or staged colectomy resection of
liver/lung secondary.
• 2. Neoadjuvant chemotherapy with
FOLFOX/CapOX for 2-3 months and resection of
liver/lung secondary.
• 3. colectomy followed by chemotherapy with
FOLFOX/CapOX for 2-3 months and resection of
lung/liver secondary.
• Presently all the above protocols have shown to
be equally effective in terms of disease free
survival and overall survival.
• It is recommended to give 6 months of
perioperative chemotherapyto patients with
metastatic colon cancer.
• Local ablative therapy such as image guided
radiation therapy (IGRT) AND STEROSTATIC BODY
radiation therapy(SBRT) may considered in highly
select patients with oligometastatic liver/lung
disease.
 Role of radiation therapy in colon
cancer
• Neoadjuvant radiotherapy along with concurrent 5-FU based
chemotherapy regime may be considered in select patients with T4
tumours with penetration to fixed structures to aid resection
• Patients who are medically unfit for surgery and patients with
recurrent disease
• Recommended dose of radiotherapy is 45-50Gy in 25-28 fractions
• IORT has been shown to be beneficial in providing an additional
booster dose of radiotherapy to the target anatomical part .
• IMRT should be considered only for patients who have been already
trated and present with recurrent disease.
• Intra arterial catheter therapy with yittrium -90 microspheres can
be considered in highly select patients with chemotherapy resistant
tumours and those with predominantly liver mets.
 Use of monoclonal antibodies

• EGFR and VGEF antibodies have been syudied for

targeted therapy either as monotherapy or in
combination with systemic therapy.
• Anti VEGF monoclonal antibodies – bevacizumab
• Anti EGFR monoclonal antibody
cetuximab/panitumumab
• These show significant improvement in the
median survival show in many trials ,monoclonal
antibodies are now recommended as first line
chemotherapy for metastatic colorectal cancer.
 Ongoing research which may impact
future practice
• Nanotechnology has been shown to have early detection
and treatment of colorectal cancer .
• Nanoparticle based identification of specific tumour
location ,biologically targeted contrast agents (Ironoxide
nanocrystals contrast agent in MRI) and drug delivery
system (PLGA nanoparticle as a 5 -FU carrier at the point of
DNA damage)have been studied. This has a potential for
future diagnostic and therapeutic role in colon cancer
patients .
• Near infrared (NIR) florescence imaging using NIR
florescent nanoparticles has been shown in experimental
models . This has a potential to replace invasive
colonoscolpy.
Thank you.
 References

• Short practice of surgery bailey and love’s 27th

edition.
• Sabiston textbook of surgery.
• Roshan lal gupta’s recent advances in surgery.