Diagnosis and Staging of Lung Carcinoma With CT Scan and Its Histopathological Correlation
Diagnosis and Staging of Lung Carcinoma With CT Scan and Its Histopathological Correlation
Diagnosis and Staging of Lung Carcinoma With CT Scan and Its Histopathological Correlation
DOI: http://dx.doi.org/10.18203/2320-6012.ijrms20172086
Original Research Article
1
Department of Radiodiagnosis, Government Medical College, Surat, Gujarat, India
2
Department of Radiodiagnosis, SMIMER, Surat, Gujarat, India
*Correspondence:
Dr. Dhara Shah,
E-mail: monadigant@hotmail.com
Copyright: © the author(s), publisher and licensee Medip Academy. This is an open-access article distributed under
the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial
use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
Background: Lung cancer is the most common cancer worldwide. Hence, timely diagnosis and accurate staging of
the carcinoma is critical for the treatment and prognosis. So, this study was performed to evaluate the role of CT scan
in diagnosis and staging of lung cancer.
Methods: This was a prospective and observational study carried out over one and half years at a tertiary care
hospital. The patients found to have abnormalities on chest X-ray suggestive of carcinoma were included in the study.
Pre and post contrast CT scans were performed. Individual patient biopsies were done for histopathological staging.
Results: Most patients belonged to 41-50 years age group with male preponderance (81.33%). Habit of smoking was
prevalent among the lung cancer patients. Almost all masses (92%) showed heterogeneous contrast enhancement on
CT. Additionally, there were calcifications, cavitation, hilar enlargement, pleural invasion, mediastinal
lymphadenopathy and contiguous bone involvement. Adenocarcinoma was the most common (46.66%) form of
cancer followed by squamous cell carcinoma (42.66%). For histopathological diagnosis, majority of patients
(73.33%) were diagnosed using CT guided biopsy. In the remaining patients, USG guided biopsy or fibreoptic
bronchoscopy were performed. The most common lobe affected by bronchogenic carcinoma was right upper lobe.
The most common site of metastasis was pleura (22.66%) followed by bone (17.33%). Majority of the patients
(41.33%) presented with TNM stage IV.
Conclusions: CT scan as a modality for detection and staging of bronchogenic carcinoma is superior to chest
radiograph. CT guided FNAC has a high success rate in evaluation of lung carcinoma.
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Shah D et al. Int J Res Med Sci. 2017 Jun;5(6):2346-2352
and patient prognosis are directly related to the stage at All the patients were followed for their histopathological
presentation. Computed tomography (CT) scan is the diagnosis. Comparison between probable
standard imaging modality used for the evaluation of histopathological diagnosis on radiological appearances
bronchogenic carcinoma. Accordingly, this study was and final laboratory histopathological diagnosis was
carried out with an aim to evaluate and correlate various done. For histopathological diagnosis, individual methods
radiological CT findings with histopathological diagnosis of biopsy, namely Ultrasound guided FNAC, CT guided
and for proper staging of bronchogenic carcinoma based biopsy and fibreoptic bronchoscopy, were performed.
on the revised international system classification scheme Patients were further followed up for treatment, but as
- T (primary tumor), N (nodal involvement) and M most of them presented with extensive disease, they were
(metastatic disease) staging. Also, the diagnostic lost to follow up.
accuracy and limitations of CT and transthoracic
percutaneous fine needle aspiration cytology (FNAC) in RESULTS
planning the treatment of bronchogenic carcinoma is also
highlighted. In this study, 75 patients were enrolled based on the
inclusion criteria. The peak age prevalence of the patients
METHODS of Bronchogenic carcinoma was 41 - 50 years. Table 1
shows the prevalence of subtype of bronchogenic
This was a prospective and observational study carried carcinoma in relation to the age of the patient. Out of 75
out for duration of 1 and half years in the Department of patients, 61 were male and 14 were female. Thus,
Radio diagnosis of tertiary care hospital and medical incidence of Bronchogenic carcinoma was more in males
college, Surat. The study was commenced after approval (81.33%) as compared to females (18.66%).
from institutional ethical committee.
Table 1: Histological cell type of bronchogenic
The criteria for selection of patients were carcinoma in relation to age.
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Shah D et al. Int J Res Med Sci. 2017 Jun;5(6):2346-2352
No. of % of
Findings
cases cases
Pattern of enhancement 69 92
Calcification 24 32
Cavitation 07 9.33
Hilar enlargement 13 17.33
Distal collapse 35 46.66
Figure 2: The same lesion on lateral X-ray extending
Pleural effusion 16 21.33
and surrounding the hilum and main stem bronchus.
Mediastinal lymphadenopathy 16 21.33
Mediastinal Invasion 24 32
Rib, chest wall and pleural
17 22.66
invasion
SVC compression 04 5.33
Vertebral Invasion 02 2.66
Figure 1: Large soft tissue opacity lesion in left Figure 4: The mass shows heterogeneous
hilar/perihilar region with broad base towards enhancement with few traversing vessels are seen
mediastinum. Rest of lung fields appear normal. and causing narrowing of left main stem bronchus.
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Shah D et al. Int J Res Med Sci. 2017 Jun;5(6):2346-2352
Broncho- Neuro-
Squamous cell Adeno Non-diffentiated
Radiographic Finding alveolar endocrine
carcinoma carcinoma carcinoma
carcinoma tumor
Hilar, perihilar mass or
5 8 - - -
prominence
Pulmonary lesion < 4 cm 4 6 2 - -
Apical mass 4 3 - - -
Pneumonitis collapse or
9 3 1 - -
consolidation
Mediastinal involvement 12 12 - 1 -
Chest wall lesion 10 7 - 1 -
Pleural effusion 8 7 - 1 -
For histopathological diagnosis, majority of patients more frequently (n = 42) as compared to middle and
(73.33%, n = 55) were diagnosed using CT guided biopsy lower lobes. Table 4 shows the sites of origin of different
(Figure 5). USG guided biopsy was performed in 12 histopathological subtypes of lung cancer in all the
(16%) cases and fibreoptic bronchoscopy in 08 (10.66%) patients. Adenocarcinoma was most prevalent cell type in
cases. The most common complication of CT guided upper lobe and middle lobe carcinomas; while squamous
FNAC was pneumothorax which occurred in 2 patients. cell carcinoma was most common in lower lobe and as
hilar mass.
The most common lobe affected by bronchogenic
carcinoma was right upper lobe. The ratio of involvement Table 5 shows the lymph node involvement in various
of right lung to left was 39:34. Upper lobe was affected histological subtypes. A size criterion of 10 mm in
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Shah D et al. Int J Res Med Sci. 2017 Jun;5(6):2346-2352
smallest diameter was considered as suggestive of lymph stage, 3 in N2 stage and 2 in N1 stage. Table 6 shows the
node involvement. Among the cases of squamous cell distribution of metastasis at the time of diagnosis in
carcinoma, 6 patients were in N3 stage and 1 in N2 stage, patients with bronchogenic carcinoma.
while in adenocarcinoma cases, 6 patients were in N3
Table 5: Histopathological cell type of bronchogenic carcinoma in relation to lymph node involvement.
Table 6: Distribution of metastasis in bronchogenic carried out with an aim to evaluate the role of one such
carcinoma. imaging technique i.e. CT scan in the diagnosis and
staging of lung cancer. In present study, the most
Site No. of cases % of cases common age group affected with lung carcinoma was 41-
Lungs 05 6.66 50 years of age. There was a predominance of male
Pleura 17 22.66 patients. This may be due to higher incidence of smoking
Liver 09 12 in male population. In the present study, high degree of
association was found between smoking and incidence of
Adrenal 06 8
lung cancer. 82.66% of patients were chronic smokers.
Brain 06 8 Smoking, especially of cigarettes, has been clearly
Bone 13 17.33 established in the literature as a major risk factor for the
Spleen 02 2.66 development of lung cancer.3
GIT 01 1.33
Cough with expectoration was found to be the most
Table 7: Non-small cell carcinoma: extension of common symptom followed by dyspnoea on exertion and
disease at the time of presentation. chest pain. These are well documented in various
textbooks as the most common signs and symptoms
Stage No. of cases % of cases which suggest lung cancer. These are divided into
I 11 14.66 respiratory symptoms such as coughing, hemoptysis,
II 18 24 dyspnea; systemic symptoms such as weight loss, fever,
III A 05 6.66 clubbing and symptoms due to the pressure on adjacent
III B 08 10.66 structures such as chest pain and bone pain.4 In the
IV 31 41.33 present study, adenocarcinoma (46.66%) occurred most
frequently followed by squamous cell carcinoma
The most common site of metastasis was pleura (22.66%) (42.66%). This is in contrast to some of the previous
followed by bone (17.33%) and opposite lung (6.66%). Indian studies which showed squamous cell carcinoma to
be the most frequent subtype; but similar to the findings
Among the contiguous bone metastasis, intraspinal
of some recent studies in India which shows a changing
extension was most commonly found (n =5) followed by
pattern of lung carcinoma from squamous cell carcinoma
sternum, ribs and vertebra. Table 7 gives the TNM
to adenocarcinoma.5-8 This change may be due to changes
staging of the non-small cell lung cancer at the time of
presentation. Majority of the patients (41.33%) presented in smoking habits. Most of the masses (92%) showed
heterogeneous contrast enhancement on CT scan. In
with stage IV advanced disease and metastasis. One case
addition, there was calcification, cavitation, hilar
was diagnosed in TxNoMo stage. In our study, only one
enlargement, distal collapse, pleural effusion, mediastinal
case of small cell carcinoma had been reported in limited
lymphadenopathy, mediastinal invasion, SVC
stage (IA).
compression, ribs, chest wall and vertebral invasion.
Atelectasis is more commonly caused by endobronchial
DISCUSSION
carcinoma and rarely by surrounding bulky lymph nodes.
Because airway obstruction is usually complete, air
The incidence of lung cancer is continuously increasing
cannot pass distally and air bronchogram is thus absent.
globally in both men and women. Availability of newer
This sign is virtually pathognomonic of an endobronchial
imaging techniques has made it possible to diagnose
obstructing lesion.
bronchogenic carcinoma in the earlier stages and thus
improves the prognosis of the patients. This study was
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Shah D et al. Int J Res Med Sci. 2017 Jun;5(6):2346-2352
Woodring JH described that the radiographs are more However, none of the patients required a chest tube drain.
specific than CT for tumor as a cause of atelectasis (96 Geragthy et al, described significant increase in rate of
versus 87%), but it is less sensitive than CT for tumor pneumothorax seen in patients older than 60 years. There
(89% versus 100%) resulting in missed tumor diagnosis.9 was a significant increase in rate of pneumothorax with
In our study, out of 35 patients presenting with 18G compared with 19.16 USG guided FNAC was done
atelectasis, in 3 patients underlying tumor was not in pleurally based bronchogenic carcinoma as it is helpful
diagnosed on radiographs but all the patients were in the form of short procedure time, especially helpful in
diagnosed as having distal atelectasis due to tumor on CT less cooperative patients, in tumour exhibiting central
scan. White et al. demonstrated that endobronchial necrosis. Fibreoptic bronchoscopy was done in central
location and lower lobe predominance were the most endobronchial mass, cavitating lesions or lesions that
common characteristics of overlooked lung cancer on CT were immediately adjacent to heart or usually best
scan.10 Patz et al described that non-enhanced CT thorax approached first via the bronchoscope. Using flexible
through adrenal gland is sufficient for successful staging bronchoscope diagnostic accuracy is upto 95% for lesions
and contrast-enhanced CT (CECT) thorax did not visible through microscope; but the procedure is time
substantially alter the tumor staging.11 However, in this consuming and more expensive. Laroche et al, described
study CECT was done in majority of the patients to the role of CT thorax prior to bronchoscopy in the
differentiate necrotic part of the tumor through which investigation of suspected lung carcinoma as it may
biopsy should be avoided and it was helpful in provide staging, relation, road map, site of biopsy and
distinguishing central partially obstructing endobronchial other associated lesions or findings on CT may obviate
mass from more distal collapsed or consolidated lung. In the need for bronchoscopy.17
our study, 16 patients had pleural effusion but it was not
possible to differentiate benign from malignant effusion The most common lobe affected by lung cancer in our
from CT scan. study was found to be right upper lobe. This is similar to
the findings of Garland et al. which described the lobar
In present study, the most common presentation for chest distribution of bronchogenic carcinoma in 250 cases and
wall invasion was loss of fat plane with the pleura. It is a found relative frequency of 3:2 in right versus left lung
sensitive criterion but not specific because contiguity of and upper versus lower lobe.18
tumor with parietal pleura was found not to be equivalent
with definite invasion of chest wall, even when Ipsilateralmediastinal lymph nodes were most commonly
associated with pleural thickening. Erosion of a rib is a involved in all the subtypes of bronchogenic carcinoma.
highly specific but not sensitive criterion. Pennes et al Quinn et al. reviewed the radiographic presentation in
described CT criteria for chest wall invasion and 345 cases. Mediastinal lymph nodes were seen in 62%
concluded that CT is not accurate in assessment as small cell carcinoma, 36% adenocarcinoma, 32% large
criteria are either highly sensitive and non-specific or cell carcinoma and 26% squamous cell carcinomas.19
vice versa.12 Kuriyama et al found that lesions classified Metastasis was most common in pleura followed by bone
as T1 on two dimensional axial CT images were correctly and opposite lung. Riihimaki M et al conducted a
reclassified as T2 (visceral pleural invasion) or T3 population-based survey and concluded that bone (39%)
(parietal pleural involvement) on 3D images in 10-46 and respiratory system (22%) metastases were common
patients. The sensitivity of pleural puckering was high, in patients with adenocarcinoma andliver (35%) and
but specificity was only 76% because it was not only seen nervous system (47%) metastases in patients with small
with tumor invasion but also with reactive fibrotic cell lung cancer.20
changes.13
There are certain limitations of CT scan when used for
CT guided biopsy was done in majority of the patients. diagnosis and staging of lung cancer. The use of CT scan
CT guided FNAC is especially useful when the peripheral for detection of tumor invasion to adjacent structures
lesion is not approachable by US, or if the lesion is such as pleura and chest wall is less specific and less
adjacent to hilum, mediastinum, aorta or heart. In our sensitive. Also, it has low sensitivity and specificity for
study, we had done CT guided FNAC from the peripheral determination of nodal status based on the fact that
lesions as well as bulky mediastinal lymphadenopathy enlarged lymph nodes may be hyperplastic rather than
adjacent to vessels in selected patients. Singh JP et al. neoplastic and normal sized lymph nodes may contain
concluded that CT guided FNAC is highly sensitive and neoplastic cells. Thus, CT can both understage as well as
specific technique with good diagnostic accuracy and can overstage bronchogenic carcinoma. Also, CT guided
be used safely as an outpatient procedure for the FNAC can be inconclusive because of low cell yield.
diagnosis of thoracic masses.14
CONCLUSION
Li et al, described diagnostic accuracy of CT guided
biopsy as significantly less for small lesions as compared CT scan as a modality for the detection of bronchogenic
to large nodules but the complication rates for both are carcinoma is superior to chest radiograph. Staging of T1
low.15 Pneumothorax was the commonest complication in and T2 tumors is based almost exclusively on CT
our study which occurred more with 18 gauge needles. scanning. Major extra thoracic sites of metastasis such as
International Journal of Research in Medical Sciences | June 2017 | Vol 5 | Issue 6 Page 2351
Shah D et al. Int J Res Med Sci. 2017 Jun;5(6):2346-2352
liver and adrenals are well studied using CT thorax with lung overlooked at CT: analysis of findings in 14
high accuracy. But the situation becomes more difficult patients. Radiol. 1996;199(1):109-15.
with T3 and T4 tumors where the differentiation is 11. Patz EF, Erasmus JJ, McAdams HP, Connolly JE,
critically important for determining the course of Marom EM, Goodman PC, et al. Lung cancer
treatment. So, other modalities such as PET scanning, staging and management: comparison of contrast-
MDCT can be used to complement CT for further enhanced and nonenhanced helical CT of the thorax.
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SPECT has a promising future for staging and 12. Pennes DR, Glazer GM, Wimbish KJ, Gross BH,
intervention. Long RW, Orringer MB. Chest wall invasion by
lung cancer: limitations of CT evaluation. Am J
Funding: No funding sources Roentgenol. 1985;144(3):507-11.
Conflict of interest: None declared 13. Kuriyama K, Tateishi R, Doi O, Higashiyama M,
Ethical approval: The study was approved by the Kodama K, Inoue E, et al. Prevalence of air
Institutional Ethics Committee bronchograms in small peripheral carcinomas of the
lung on thin-section CT: comparison with benign
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