Cancer of the colon and rectum in high-risk patients

Prognosis of colorectal cancer varies in different high-risk conditions

Variation in prognosis between different colorectal cancer (CRC) patient groups was studied by comparing the survival rates of patients belonging to three cancer predisposition groups with those with sporadic CRC. The high-risk groups included 43 members of hereditary nonpolyposis colorectal cancer (HNPCC) families, 25 patients with familial adenomatous polyposis (FAP) and 33 patients with underlying ulcerative colitis (UC). The control group included 122 consecutive sporadic CRC patients. Cumulative 5-year survival was highest in HNPCC (86%), which is significantly better than in sporadic colorectal cancer (59%, hazard ratio 0.41, P = 0.02). Cancer associated with UC had a 5-year survival rate of 39%, which is significantly less than in sporadic cancer (hazard ratio 1.83, P = 0.03). There was no significant difference in the survival between patients with FAP and patients with sporadic CRC (hazard ratio 1.27, P = 0.5). Exclusion of cases detected by screening examinations slightly reduced the survival rates; 85% for HNPCC, 53% for FAP and 28% for UC. However, the differences between the groups remained significant. The survival of patients with HNPCC was found to be better than that among other groups in this study, which probably relates to the specific tumourigenesis involving DNA mismatch repair dysfunction.

Improvements in the treatment and prognosis of colorectal carcinoma

In a survey of the surgical results in 709 patients with colorectal carcinoma (CRC) treated between 1976 and 1985 a favourable shift of stage distribution was observed. The tumour was localized (Dukes' classification A or B) in 61 per cent of patients, as compared with 47 per cent in the previous 10-year period. This change was, in part, due to different interpretation of stage definitions. Clear improvements of the results were, however, also noted. Radical surgery was possible in 76 per cent of patients and the primary tumour was removed in 93 per cent. Surgical mortality was 4.4 per cent and complication rate 15 per cent, significantly less than earlier (6.5 and 38 per cent, respectively). Increasing numbers of sphincter-saving operations were performed in rectal cancers (47 per cent as compared with 24 per cent in the previous 10-year period). The overall 5-year survival rate improved from 40.5 to 52.5 per cent. Premalignant conditions were identified in 12.6 per cent of patients: previous CRC 4.8 per cent, cancer family syndrome 4.1 per cent, ulcerative colitis 1.7 per cent and familial adenomatosis 0.6 per cent. In order to sustain the favourable trend of improving survival prospects, more emphasis must be directed to the detection of early stage cancers.

The pros and cons of fecal occult blood testing for colorectal neoplasms

Testing feces for occult blood is widely recommended as a means of detecting subclinical colorectal tumors. Guaiac tests such as Hemoccult are the most widely used, but chemical sensitivity is relatively low and the tests are affected by dietary peroxidases, the state of fecal hydration, and certain drugs. The newly devised HemoQuant and immunologic techniques appear more sensitive and specific, but they require further evaluation before widespread clinical usage can be recommended. Occult blood screening has both merits and weaknesses. Testing does uncover subclinical colorectal cancer, often at a relatively early stage, but whether this actually improves the prognosis remains to be proven. Benign neoplastic polyps are also detected, although it is debatable whether this is a valid rationale for screening. Test sensitivity for malignancy varies from good to moderate, but is poor for benign polyps. Specificity is usually around 97%-98%, yet the predictive value of a positive test for cancer is only about 10%; hence most test-positive individuals are needlessly subjected to invasive colonic investigations. Reported figures on public compliance with occult blood testing vary widely from excellent to poor. Published costs of screening are usually quite low, but these overlook important indirect and hidden expenses and are therefore misleading. On balance, the problems of occult blood testing currently appear to outweight the merits. This could change, however, with the newer testing techniques and with awaited mortality data from controlled clinical trials now underway.

Surgical results in 657 patients with colorectal cancer

Six hundred fifty-seven patients with colorectal cancer who were operated upon at the Second Department of Surgery, Helsinki University Central Hospital during the period 1966 to 1975 had a 40.5 per cent crude five-year survival rate and 54.2 per cent relative (corrected) rate. The survival rates of patients with Dukes' A lesions were 80.7 per cent, Dukes' B, 61.6 per cent, Dukes' C, 40.4 per cent, and Dukes' D, 2.7 per cent. One hundred two patients (15.5 per cent) underwent emergency operations; 91 were occlusive cancers, eight were perforations and three were cancer bleedings. The operative mortality for the whole series was 6.5 per cent (4.7 per cent in elective and 16.7 per cent in emergency operations). A definite improvement of the five-year survival rates could be seen in both the colonic and rectal cancer series. This was due to earlier detection of the disease, reflecting a decreasing number of palliative operations. Patients at high risk for colorectal cancer (inflammatory bowel disease, inherited intestinal polyposis, cancer family syndrome, multiple colorectal cancers, and neoplastic polyps) might benefit from more effective cancer surveillance and prophylactic surgery to find and treat cancers in earlier stages, to prevent recurrences, and to facilitate follow-up. The controversial findings on postoperative adjuvant therapy presented in this study indicate the need for further controlled studies to define the patients who really benefit from it.