Influence of anatomical extent and age at onset on colitis - cancer interval

We have examined the age at onset of both ulcerative colitis and colitis-associated colorectal cancer in 100 patients seen atMount Sinai Hospital between 1959 and 1988. There were 85 patients with extensive colitis and 15 with left sided colitis. There was a strong direct correlation between the age at onset of ulcerative colitis and age at diagnosis ofcancer (p<0.0001); this correlation was found both in patients with extensive colitis (p<0.0001) and in those with left sided colitis (p<0.005). Patients with left sided colitis developed both their colitis and their cancers about a decade later than did those with extensive disease, but the mean duration of colitis before diagnosis of cancer was virtually the same (about 21 years) in both groups, irrespective of the age at onset of disease. Departments of Surgery, Biomathematical Sciences, and Medicine (Division of Gastroenterology), Mount Sinai School of Medicine of the City University ofNew York, New York A Sugita D B Sachar C Bodian M B Ribeiro A H Aufses Jr A J Greenstein Correspondence to: Dr Adrian J Greenstein, Department of Surgery, Box 1259, Mount Sinai Medical Center, One Gustave L Levy Place, New York, NY 10029, USA. Accepted for publication 5 March 1990 Although colorectal cancer is a relatively rare complication of ulcerative colitis,12 the cancer incidence in patients with ulcerative colitis is higher than that in the general population.2 Suggested risk factors for the development of colitis-associated colorectal cancer include age at onset, duration, and anatomic extent of ulcerative colitis. The relative importance of these factors remains controversial. The increasing use of surveillance programmes`' makes it even more critical that the factors associated with the increased colorectal cancer risk be clarified. Only if these factors are clearly defined can a rational and scientific approach to surveillance be proposed. We have examined these factors in 100 patients with colitis-associated colorectal cancer seen at Mount Sinai Hospital, for whom complete information was available. Patients and methods Retrospective review of the case records of all Age data for ulcerative colitis-associated colorectal cancer Statistical All cases Universal colitis Left sided colitis significance (n=100) (n=85) (n=1S) (t test) Age at onset of ulcerative colitis: Mean (SD) 271 (11-2) 25-4(10-7) 36-7(12-9) p<0O0003 Median (range) 26 (1-56) 25 (1-56) 39 (17-56) Age at diagnosis of cancer: Mean (SD) 47-7 (13-9) 45-9 (13-4) 58-3 (12-3) p<00012 Median (range) 48 (19-77) 47 (19-77) 56 (40-76) Duration from onset of ulcerative colitis to diagnosis of cancer: Mean (SD) 20-7 (9.2) 20-5 (9-1) 21-5 (9.6) Not Median (range) 20 (5-46) 19 (7-46) 22 (5-40) significant patients with ulcerative colitis admitted to Mount Sinai Hospital between January 1959 and March 1988 showed 102 patients with colorectal cancer. Two patients were excluded from our study. In one no information was available about the onset ofulcerative colitis, and in the other the extent of colitis could not be ascertained. The diagnosis of ulcerative colitis was made by clinical evaluation, barium enema, colonoscopy, and pathological examination of surgical specimen after colectomy. Other inflammatory bowel diseases such as Crohn's disease and infectious colitis were excluded. Left sided colitis was defined as disease starting distal to midtransverse colon, and extensive colitis as any disease beginning more proximal, by gross pathological examination of the colectomy specimen. The three major factors recorded for each patient were age at onset of ulcerative colitis, age at diagnosis of colorectal cancer, and duration from onset of ulcerative colitis to diagnosis of colorectal cancer. Linear regression analysis and Student's t test were used for statistical analysis. Results Among the 100 patients with colorectal cancer, there were 85 with extensive colitis and 15 with left sided colitis. Age data on these patients are summarised in the Table. Age at onset of ulcerative colitis (Fig 1). In all patients in the series the mean age at onset of ulcerative colitis was 27-1 years (median 26 years, range 1-56). The onset of left sided colitis occurred approximately a decade later (mean