Relationship between degree of cellular differentiation in colorectal cancer and topographical distribution

To demonstrate the relationship between degree of cellular differentiation in colorectal cancer and topographical distribution in 215 patients diagnosed with colorectal cancer from 1997 to 2000.

215 patients (129 men and 86 women) were studied prospectively with a mean age of 64 years (range: 23-84 years). In all patients we performed a full colonoscopy with several biopsies (in patients with colon stenosis we used barium enema), radiographic studies (CT, abdominal ultrasounds), and laboratory tests for serum tumour markers (CEA, Ca 19-9, alpha-fetoprotein). The topographic location of colorectal cancer was: rectum 35%, sigmoid colon 31%, descending colon 10%, transverse colon 6%, ascending colon 9%, caecum 5%, and we included anorectal cancer 4%.

According to histological differentiation we found: A) well-differentiated tumours 101/215 (47%); B) moderately-differentiated tumours 98/215 (45.5%), and C) poorly-differentiated tumours 16/215 (7.5%). We found no significant association among histological differentiation, topographic location, stage according to the Astler-Coller classification, sex or age (p = ns). The prevalence of well-differentiated tumours in men was 49% and 43% in women; of moderately-differentiated cancers in men was 43%, and 49% in women; for poorly-differentiated tumours in men was 7.5%, and 7.2% in women. Regarding tumour location, 165 cancers were found in the left colon: 80 were well differentiated, 77 moderately differentiated and 8 poorly differentiated. In the transverse colon we found 12 tumours: 7 well differentiated, 3 moderately differentiated and 2 poorly differentiated. 30 cancers were localized in the right colon: 11 well differentiated, 15 moderately differentiated and 4 poorly differentiated. In the anorectum 8 tumours were found: 3 well differentiated, 3 moderately differentiated and 2 poorly differentiated. According to staging classification, well differentiated tumours (101/215) were more common in Dukes' C2 (20.7%) and B1 (32.6%), moderately differentiated cancers (98/215) were in B1 (28.5%) and C2 (20.4%), and poorly differentiated tumours (16) were more common in Dukes' C2 (25%), without differences among other stages (p = ns).

According to our results we have found that histological differentiation of colorectal cancer has no association with topographic location, and it is independent of sex or age. We have not found any relationship either between histological differentiation and stage in the Astler-Coller classification, but well differentiated cancers were more common at any location, age or sex.