Demographics, pathologic patterns and long-term survival in operable colon cancers: local experience in Pakistan

Colon cancer is a common malignancy with its incidence reportedly rising in Asian countries, including Pakistan. There are no comprehensive data available from Pakistan which focus on associations of various factors with long-term survival of colon cancer. We therefore present an analysis of findings from our centre.

In this retrospective study adult patients with colon cancer diagnosed through 2000-2003 were included. A comprehensive questionnaire was filled for each individual through review medical and pathology reports. Long term survival data was collected from contactable patients or their relatives.

A total of 93 patients were assessed, 57 males and 36 females (M: F= 1.58: 1). Mean age of diagnosis was 54 years. Of the total, 49.5% of the patients had right sided (mortality rate 51.6%), 10.8% had transverse colon, (mortality rate 37.5%), 7.5% had descending colon (mortality rate 66.7%) and 32.2% had sigmoid colon (mortality rate 40.9%) cancers. Stage I disease on diagnosis was found in 16%, stage II in 42.7 (mortality 40 %) and stage III in 41.3% (mortality 70 %). Tumors were well differentiated in 20.2% (mortality 42.9%), moderately differentiated in 61.9% (mortality 43%) and poorly differentiated in 17.9% (mortality 70%). In 36.3% of the patients less than 12 lymph nodes were removed (mortality 55% Vs 43% in patients with <12 lymph nodes removed). Margins were free in most patients but a radial margin was reported in only 44%. Most patients had pure adenocarcinoma while a mucinous type differentiation was seen in 19.7%, 3% had signet ring morphology, 1.5% adeno-squamous carcinoma and similar number with neuroendocrine differentiation. Overall 5 year all cause mortality for all stages combined was 46.9%.

Colon cancer in Pakistan commonly presents at an advanced stage, there is a male preponderance, and relatively mean younger age at presentation for males is seen. Advanced stage and lymph node involvement along with poorly differentiated pathology, signet ring or mucinous morphology, location in descending colon, positive surgical margins and removal of less than twelve lymph nodes are factors associated with poor long term survival. There is a need to reinforce information about colon cancer and larger studies from the region are needed to confirm the factors analyzed here.