No abstract

Of 4583 patients in the Large Bowel Cancer Project, 713 (16 per cent) were obstructed. The site of greatest risk was the splenic flexure (49 per cent). Advanced stage was neither the full reason why some patients obstructed nor for their subsequent poor prospects (age-adjusted 5-year survival: not obstructed, 45 per cent; obstructed, 25 per cent). Also, there was no greater risk of vascular invasion, no heavier lymph node burden and no worse tumour differentiation in patients with obstruction. In-hospital mortality was high (23 per cent), was not reduced by either a policy of primary or staged resection and was not influenced by the site of obstruction. There was no survival advantage for either policy, but hospital stay after primary resection was half that of staged. Immediate anastomosis in the obstructed left colon had a high clinical leak rate (18 per cent versus 6 per cent elective; P less than 0.001). Both registrars and consultants had similar mortality rates for elective primary resection and for the management of obstruction itself (as evidenced by results after the first stage of a staged resection). Selection probably accounts for the very much better results achieved by consultants for primary resection in the presence of obstruction (in-hospital mortality: consultants, 13 per cent; registrars, 24 per cent).

The Large Bowel Cancer Project is a collaborative prospective study of 4228 patients with a histologically proven adenocarcinoma, of whom 2336 (55 per cent) survived a 'curative' resection. Follow-up information is available on 2220 patients (95 per cent). Subsequently, 309 (14 per cent) have developed a local recurrence confirmed by: biopsy (127; 41 per cent), clinical examination (77; 25 per cent), X-ray (15; 5 per cent), a raised CEA (2; 1 per cent), or some other method - e.g. CT scan or a confident unbiopsied laparotomy finding (88; 29 per cent). Statistically significant factors (chi2 test, P less than 0.05) associated with local recurrence are: Dukes' classification: A 4 per cent; B 13 per cent; C 18 per cent Tumour differentiation: Well 11 per cent; Moderate 14 per cent; Poor 21 per cent Obstruction: Absent 13 per cent; Present 21 per cent Perforation: Absent 13 per cent; Present 28 per cent Tumour mobility: Freely mobile 11 per cent; Others 21 per cent Operation performed (rectal and rectosigmoid tumours): Abdomino-perineal 12 per cent; Anterior resection 18 per cent; Surgeon (Consultant only): Range less than 5 per cent to greater than 20 per cent. Stratification of the above variables altered only the statistical significance pertaining to tumour differentiation (P less than 0.1, d.f. = 2). In particular, the differences between Consultant surgeons remained.

To demonstrate any difference in outcome between patients with carcinoma at various sites within the large bowel, analysis of a large number of patients is necessary. From the Large Bowel Cancer Project, 4292 patients have been evaluated to compare mode of presentation, surgical management, pathological findings and outcome. Carcinoma at the splenic flexure was associated with the highest risk of obstruction (49 per cent); postoperative cardiopulmonary complications (36 per cent); in-hospital mortality (18 per cent); and the lowest age-adjusted 5-year survival (28 per cent), even after curative resection (38 per cent). This survival disadvantage was seen even in those without obstruction. Further, it was not accounted for by differences in age, sex, Dukes' stage or tumour differentiation between the various sites as stratification by these variables failed to alter significance (log rank chi 2 = 11.1; d.f. = 4; P less than 0.05). Compared with carcinoma of the left colon and rectum, tumours in the right colon were more likely to be poorly differentiated and locally advanced (in terms of fixation and penetration of the bowel wall) but were not associated with a higher risk of either distant spread at presentation or local recurrence. Age-adjusted 5-year survival following curative surgery was higher for the right colon (65 per cent) than the left (59 per cent).