Though the incidence of obstructive colorectal cancer (OBCR) previously reported to peak in the seventh and eight decades of life , it is nowadays increasing in the younger age group especially in Asian countries, with mean age of 49.78+/- 15.96 years in our study with 1/4th of the patients being younger than 40 years of age. However, there continues to have no difference in the incidence of OCRC among genders that is, 14(50%) males and 14(50%) females in our study.
Generally, colorectal cancer (CRC) incidence has been higher in the urban areas of economically advantaged countries . This is thought to be related to consumption of a high fat / high red meat diet and lack of physical activities with resulting obesity. However, OCRC is found to be common in rural areas of the eastern Nepal that is 16(57%) patients from such areas in our study. There can be two separate reasons for this occurrence: one, relative lack of awareness of CRC and its screening program implementation; two, delayed presentation of patients to health care system in the rural areas.
Most common presenting feature in our patients was abdominal pain in 14(50%) patients followed by altered bowel habit, blood in stool, abdominal distention, anorexia, abdominal mass, weight loss, anemia, tenesmus, vomiting and bleeding per rectum respectively, similar to other studies in literature . Overall, of 28 patients with OCRC, 21.4% patients had complete bowel obstruction while remaining had partial bowel obstruction. Various diagnosing modalities used in our study included abdominal x-ray (in 100% cases), ultrasonoghraphy of abdomen and pelvis (in 92.8% cases), abdominal CT-scan (in 85.7% cases), colonoscopy (in 78% cases), serum CEA level (in 75%cases), pre-operative punch biopsy (in 28.6% cases) and Faecal occult blood test (in 3.6% cases).
Classically, the distal colon was believed to be the most common site for OCRC. However, the incidence of proximal OCRC has been increasing nowadays as seen in our study that in 54% cases the lesion was in the proximal colon. Similar trends have been observed in other Asian countries too . This anatomical shift will necessarily impact on screening policy . This shift may be because of genetic factors, which can preferentially involve defects in mismatch repair genes with resulting microsatellite instability in proximal colon cancers and chromosomal instability pathway predominantly in left sided colorectal cancers.
The overall incidence of synchronous lesion in CRC has been reported to be between 2.3–12.4% in literature , however, it has been found to be a high up to 28.6% in patients with CRC presenting with either partial or complete obstruction in our study. The likely explanation can be that once patients with CRC develop obstruction, often they have advanced stage disease. It has been claimed that apart from obstructive symptoms, other symptoms do not necessarily correlate with stage of disease . In our study, the most common histological type was adenocarcinoma 28 (100%). Bowel obstruction in patients with CRC occurs when a cancerous growth or adhesion block intestinal flow. Most of patients in our study had advanced stage disease: stage 3 in 53.6% cases followed by stage 4 in 32.1% cases. Interestingly, 10% patients with OCRC were found to have stage 1 disease. The possible explanation of bowel obstruction in stage 1 disease, can be a physiological inability to move the food particles in addition to general concept of cancerous growth obstructing the lumen of bowel.
The various treatment options for OCRC opted at our centre were right hemicolectomy, extended right hemicolectomy, left hemicolectomy, extended left hemicolectomy, anterior resection, abdominoperineal resection and Hartmann’s procedure. The common post-operative complications encountered at our study were surgical site infection, hospital acquired pneumonia, anastomotic leak, prolong paralytic ileus and diarrhea. We lost one patient in post-operative period and it accounts to post-operative mortality rate of 3.6% in our study which very less in comparison to the study by Kaya S, et al . Patients averaged 13.82 days in the hospital (SD 6.87days) which is also almost half of what had been found in study by Kaya S, et al . Not all but 64.3% patients with OCRC received adjuvant chemotherapy at our center. The 1-year and 2-years disease free survivals were 89.3% and 82.1% while overall survivals were 92.8% and 82.1% respectively.