We appreciate Dr Zinner's remarks. While autopsies should provide the most accurate information in the prevalence of colonic lesions, wide discrepancies have appeared in the literature from various studies. According to one study, neoplastic lesions were discovered in about 50% of the 518 cases studied, and cancer was found in approximately 4% of the cases.1 In another study, neoplastic lesions were discovered in about 33% and cancer in approximately 2%.2
In both studies, the prevalence of neoplastic lesions increased with age. Of all the risk factors associated with colorectal cancer, age appears to be the most important by far. Accordingly, 80% of our patients were greater than 50 years of age, and the median age of our population of patients with cancer was 71. We believe that the age of our patients is an important factor in considering the number of neoplastic lesions and cancers that were detected.
Yarborough GW, Waisbren BA. High Incidence of Carcinoma-Reply. Arch Intern Med. 1985;145(9):1744. doi:10.1001/archinte.1985.00360090220050