A method for differentiating cancer prevalence according to health status, exemplified using a population-based sample of Italian colorectal cancer cases

AbstractCancer prevalence is the proportion of a population diagnosed with cancer. We present a method for differentiating prevalence into the proportions expected to survive without relapse, die of cancer within a year, and die of cancer within 10 years or survive with relapse at the end of the 10th year. Material and methods. The method was applied to samples of colorectal cancer cases, randomly extracted from four Italian cancer registries (CRs). The CRs collected data on treatments, local relapses, distant relapses, and causes of death: 1) over the entire follow-up to 31 December 2007 for 601 cases diagnosed in 2002 (cohort approach); 2) over a single year (2007) for five cohorts of cases defined by year of diagnosis (from 1997 to 2001), alive at 1 January 2007 (total 298 cases). The cohorts were combined into a fictitious cohort with 10 years survival experience. For each year j after diagnosis the health status of cases alive at the beginning of j was estimated at the end of the 10th year. From thes...