Influence of dietary factors on colorectal cancer survival.

BACKGROUND: Diet has been identified as a major determinant of colorectal cancer (CRC) but little is known of its influence on CRC survival. AIMS: To study the influence of dietary factors on survival in patients who had undergone potentially curative CRC surgery. PATIENTS: Among 171 patients included in a case control study of CRC aetiological factors, 10 year survival data on 148 patients who underwent resection of the tumour for potential cure were obtained from a Registry of Digestive Tumours. METHODS: Tertiles of food and nutrient intakes were entered into Cox proportional hazards survival models, controlling for age, sex, tumour stage, and tumour location. RESULTS: Only five year survival was influenced by the pre-diagnosis diet. High energy intake, as a result of high carbohydrate, protein, and lipid intake, was strongly related to increased survival. Five year relative risk of death for the highest versus the two lowest tertiles of energy intake was 0.18 (95% confidence interval 0.07; 0.44). This effect was similar in both sexes, for the colon and for the rectum. It was stronger in patients with N+/M+ tumours (relative risk 0.06) than in those with less advanced tumours (relative risk 0.37; stage-energy interaction term non-significant). No specific food or nutrient could be identified as having prognostic significance. CONCLUSIONS: Whether high energy intake selects less severe tumoral clones or modifies antitumoral immunity remains unclear. Larger series need to be investigated before conducting intervention studies but our findings should prompt nutritional follow up in CRC patients.

Family history and risk of colorectal cancer: implications for screening programmes.

OBJECTIVE: To estimate the lifetime risk of colorectal cancer in the general population and in first degree relatives of patients with sporadic colorectal cancer or adenoma. MAIN OUTCOMES MEASURES: The cumulative risk of colorectal cancer (0-74) in the general population combined with the relative risk of colorectal cancer and the prevalence of different groups of subjects with family history of colorectal tumour allows the calculation of cumulative risks in these groups. RESULTS: The lifetime risk of colorectal cancer was 1 in 23 in men and 1 in 40 in women. In males, 0.5% in the 55-59 age group and 4.5% in the 70-74 age group will develop a colorectal cancer. The corresponding values in females were 0.4% and 2.5%. The cumulative risk at age 74 varied between 7.7% (one family member affected) and 25.6% (two affected) in males, and 4.3% and 14.3% respectively in females. The risk in the 40-44 year age group for individuals with one first degree relative affected before 45 years of age was 0.5%, similar to that of those aged 45-49 with one first degree relative affected with a colorectal cancer or a large adenoma (> 1 cm). CONCLUSIONS: These results suggest that screening in the general population should start at 50 or 55. The lifetime risk is high enough (over 10%) among individuals with one affected first degree relative before age 45, or with at least two affected first degree relatives, to warrant colonoscopic screening. The data provide a basis for recommendations that relatives of these patients should enter screening programmes at age 40 to 44.

Colorectal cancer prevalence in France.

Cancer prevalence is a crucial indicator that allows the magnitude of the problem of colorectal cancer to be monitored. Population-based cancer registries with long-standing activity are the most appropriate tools for providing prevalence data. All colorectal cases registered between 1976 and 1995 in the Côte d'Or Cancer Registry have been considered in this study. Total prevalence (20 years) was the number of patients with a previously diagnosed colorectal cancer, alive on 31 December 1995. Cumulative recurrence rates up to 5 years after diagnosis were calculated and applied to the number of prevalent cases to estimate the number of recurrences by one-year intervals up to 5 years. The overall age-standardized prevalence rate was 170.8/100000, which yielded an estimated 185857 French people alive with a history of colorectal cancer. The 5-year prevalence rates were 149.4/100000, which represented 46.4% of prevalent cases. Five-year prevalence rates regularly increased with periods of diagnosis. These results represent useful indicators for monitoring the colorectal cancer problem and for health care planning.