Prostate cancer: how much do we know and how do we know it?

Abstract

We use data from the Massachusetts Male Aging Study to approximate the total current knowledge about prostate cancer and to evaluate the relative contributions of various risk factors. The sum total of current knowledge is assessed using the area under the receiver operating characteristic curve (AUROC) and by the Hosmer-Lemeshow statistic in a logistic regression model that includes 30 risk factors identified in the literature that are available in the data set. Relative contributions are measured using the adjusted generalized R² (AR²). To measure relative contributions, we group risk factors with similar etiology and then remove groups and compare the AR² attained without each group to the AR² with all variables included. The overall model fits adequately. The A UROC is 0.788, relatively far from its default value of 0.5, and the Hosmer-Lemeshow statistic has a p value of 0.926. We conclude that, while some knowledge about prostate cancer has been accumulated, there are still more risk factors yet unsuspected. The relative importance analysis shows that immutable factors (i.e. age, genotype) contribute 42%, dietary factors 30%, other lifestyle factors 15%, and endocrinological factors 11%. We recommend that age and other unchanging factors should be the primary focus of screening and risk evaluation and that future interventions should center on nutritional behavior.

Key Words:

• PROSTATE CANCER
• EPIDEMIOLOGY
• RISK FACTORS
• ENDOCRINE
• DIET
• BEHAVIOR