A One-year Study of Colorectal Cancer in a Tertiary Care Hospital

 

Article By:

 

S.S. Kudale

M.V. Mallya

R.G.W. Pinto

 

Abstract

 

Aim and Objectives: 1) To study the overall age and sex incidence of neoplasms of the colorectum during a period of one year; 2) To evaluate different histopathologic types; 3) To study the distribution of various tumours in relation to age, sex, and site; 4) To compare the results with similar studies done in India and other countries. Materials and Methods: The material consists of 112 specimens which includes resected specimens and biopsies of neoplastic lesions of colorectum received to the Department of Pathology, Goa Medical College. The clinical details, gross features and histopathologic details were noted. The duration of study is one year from November 2015 to October 2016. Results: Out of the 112 specimens received, there were 30.4% biopsies and 69.6% resected specimens. Most of the tumours were malignant (81.3%), whereas 18.7% were benign. Age incidence varied from 6 to 87 years. Majority of the cases were seen in the 6th decade followed by the 7th decade. Benign lesions were common in a younger age group whereas malignant lesions occurred mostly in the elderly. The incidence of colorectal tumours was marginally higher in females (50.9%) compared to males (49.1%). Rectum was the commonest site of occurrence for colorectal neoplasms. Conclusion: Incidence of malignant neoplasms of the colorectum is more than that of benign lesions. Adenocarcinoma is the commonest neoplastic lesion. Most of the polypoid lesions were adenomatous polyps.

 

Introduction:

Colorectal cancer (CRC) is a major contributor of cancer morbidity and mortality worldwide. It is the 2nd most common cancer among females and 3rd most common cancer among males.[1] Around 8% of cancer deaths are attributed to CRC thus making it the 4th most common cause of death caused by cancer around the globe. Most of the cases (about 60%) are seen in developed nations.

In India, the annual incidence rates (AAR) for colon cancer in men and women are 4.4 and 3.9 per 100000, respectively.[2] The incidence of CRC in India is comparatively lesser than that seen in the West. However, it has increased in recent years, particularly among the younger population and in the more developed states. Most of the CRCs are sporadic. Risk factors are broadly classified into genetic and environmental factors. Familial Adenomatous Polyposis (FAP) is the most important genetic factor characterised by a germline mutation in the APC gene on chromosome 5 and a high predisposition for CRC (mean age of 45 years).[2] Majority of polyps (80%) in the colorectum are adenomatous, followed by hyperplastic and juvenile polyps.[3]

 

Materials and Methods:

This is a cross-sectional observational study conducted in the Department of Pathology, Goa Medical College. The cases studied include gross specimens from patients presenting to Department of Surgery, patients referred from other medical institutions, both private and public  in  the State of Goa. The material  consists of 112 specimens which includes resected specimens and biopsies of neoplastic lesions of colorectum which were diagnosed histologically during a one-year period extending from November 2015 to October 2016.

 

The clinical data was obtained from the records on the case sheet of the patient. Information about age, sex, site of tumour, mode of presentation, and clinical diagnosis given by the surgeon were collected. The specimens were received in 10% buffered formalin. The gross appearance was described. The tissue was then subjected to routine histopathological processing. An appropriate number of paraffin sections of 4-5 micrometer in thickness were obtained and stained using hematoxylin and eosin stain. Slides were then examined under a light microscope and the microscopic appearance was noted and the tumours were histologically classified.

 

Observations and Results:

A total of 112 cases were received, of which 78 (69.6%) were resected specimens and 34 (30.4%) were biopsy specimens. Among the resected specimens, 52 (46.4%) were colectomy and 26 (23.2%) were polypectomy specimens. 21 cases (18.7%) showed benign tumors and 91 cases (81.3%) were diagnosed as malignant. The age ranged from 6 to 87 years. Majority of the cases were seen in the 6th decade (Table 1). Overall, 55 cases  (49.1%)  were  seen  in  males  and  57 (50.9%) were female patients. The commonest site of occurrence (Table 2) was the rectum with 59   cases  (52.7%),  followed   by  sigmoid  colon (20.5%, n=23), rectosigmoid junction (8.9%. n=10), descending colon (6.3%. n=7), transverse colon (4.5%, n=5) and caecum and ascending colon (3.6%, n=4 each).

TC- Apr 2018 - 023 - Overall Age and Sex incidence

TC- Apr 2018 - 026 - Histologic Types of malignancies

Malignant tumours of colorectum

The age range of malignant neoplasms was from 31 to 87 years with a mean age of 59 years (Table 3) and a maximum number of tumours between 51 and 60 years of age. In majority of the patients it was noted that they had a non-vegetarian diet. Patients with right-sided colonic neoplasms mostly presented with abdominal pain, swelling in the abdomen, and iron deficiency anaemia, whereas those with left-sided lesions presented with altered bowel habits, spurious morning diarrhoea with constipation, and patients with rectal lesions mainly presented with a mass per rectum and bleeding per rectum.

 

Of the 91 malignant lesions, 90 were adenocarcinomas, constituting 98.9% of colorectal carcinomas. A single case of Non-Hodgkin lymphoma was seen in the caecum. Immunohistochemistry, done later was positive for CD19 and CD20 which confirmed it as diffuse large B-cell lymphoma (DLBCL).

 

Adenocarcinoma was divided into three groups histologically, based on the presence of mucin production and signet ring cells into adenocarcinoma, mucinous adenocarcinoma and signet ring cell carcinoma. In the present study, a total of 82 adenocarcinomas, four mucinous adenocarcinomas and four signet ring cell carcinomas were observed (Table 4). Non-mucinous adenocarcinoma was divided into four grades based on degree of tumour differentiation, i.e. well differentiated adenocarcinoma (n=6) as seen in Figure 1, moderately differentiated adenocarcinoma (n=70), poorly differentiated adenocarcinoma (n=6) and undifferentiated adenocarcinoma (n=0).

TC- Apr 2018 - 025 - Age Incidence of malignant tumour

TC- Apr 2018 - 026 - Histologic types of malignancies

 

Polyps of the Colorectum

A total of 26 polypoidal lesions were received from the colorectum, of which 23 were benign and three were adenocarcinomas  found to arise in adenomatous polyps. Maximum polypoidal lesions encountered were adenomas (n=15, 57.7%).  Other   polypoidal   lesions   seen   were  hyperplastic polyps (n=5, 19.3%), lipomatous polyps (n=2, 7.7%) and juvenile polyp (n=1, 3.8%). Among the adenomas, one was tubular (6.7%) and the rest were tubulovillous (n=14, 93.3%) as seen in Figure 2. Most patients presented with a chief complaint  of  bleeding  per  rectum.

 

Discussion:

In the present study, the incidence of malignant lesions was much higher than benign lesions. Peak incidence of colorectal carcinoma was seen in the age group 51-60 years. Around 21% cases of cancer occurred at or less than 50 years. The risk of colorectal malignancy increases significantly after the age of 50 years. Age range of malignant tumours was observed between 31-87 years with a mean age of 59 years. These findings were similar to other studies, namely Shah et al[4] and Xu AG et al.[5]

 

Other associations are as follows: The present study shows a marginal female preponderance (male : female ratio 1 : 1.04) whereas males are seen to be affected more commonly in other studies.[6-8] Most of the patients in this study followed a non-vegetarian diet with frequent meat consumption. Majority of colorectal tumours (73.2% cases) were left-sided, i.e. mainly in sigmoid colon and rectum which is consistent with literature in India as well as abroad.[5,8,9]

 

Adenocarcinoma is the most common type of malignancy accounting for 98.9% of malignancy which is consistent with findings of other studies.[6,7,10,11] However, histological grading of adenocarcinoma varied in different studies. Certain studies such as those by Hamid et al[10] and Sharma et al[8] got higher percentages of well differentiated adenocarcinoma whereas other similar studies,[11] as well as in this present study most were moderately differentiated adenocarcinomas (Figure 1). Among polypoidal lesions, adenomatous polyps were the commonest followed by hyperplastic polyps. Similar findings were seen by Chitale.[12] Tubulovillous adenomas (Figure 2) accounted for 93.3% of all adenomatous polyps.

TC- Apr 2018 - 027 - Moderately differentiated adenocarcinoma of rectum

 

 

TC- Apr 2018 - 028 - ubulovillous adenoma of sigmoid colon

 

 

Conclusion:

 

Malignant neoplasms are more common than benign lesions in the colorectum. Patients above 50 years are affected more commonly, and the maximum incidence of both benign and malignant lesions is seen in the 6th decade. In this study, it was also seen that females were more affected (marginally) as compared to males in the present study. Rectum is the most frequent site of occurrence of neoplasms. Adenocarcinoma is the commonest tumour of colorectum. The prevalence of CRCs in age, site, and histopathological type was comparable to other studies done in India and abroad. The commonest polypoidal lesion is adenomatous polyp followed by hyperplastic polyp.

 

An increasing incidence of colorectal malignancies has been observed in patients less than 50 years of age. Family history, consumption of alcohol and red meat, obesity, and cigarette smoking are risk factors associated with malignant neoplasms in this area. Thus, any patient having a change in bowel habits, iron deficiency anaemia, abdominal pain, blood or mucus in stool, should be examined (digital rectal examination) and investigated by proctosigmoidoscopy/ colonoscopy and other radiological tests for early diagnosis and management of colorectal carcinoma.

 

TC- Apr 2018 - 029 - Writers Art pg 45

 

 

References:

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