To compare traditional prognostic characteristics of familial vs sporadic prostate cancers and to investigate potential detection biases arising from differences in the use of screening and investigative procedures.
Patients and methods
Familial and sporadic cancers were identified in a population-based sample of incident prostate cancers (total 318) in Auckland, New Zealand. To examine the potential for detection biases in these comparisons, the sociodemographic and clinical characteristics were determined according to family history status for a sample of 959 patients newly referred to Auckland urology clinics by general practitioners for the investigation of prostate-related conditions.
Compared with sporadic prostate cancers, familial cancers were more likely to be diagnosed in patients at a younger age (P=0.05), after asymptomatic serum prostate-specific antigen (PSA) screening (P=0.02), and to include a lower proportion with extraprostatic disease (P=0.009) and serum PSA levels before diagnosis of >20 ng/mL (P=0.04). This was consistent with the observed trend for patients referred to urology clinics with a positive family history to be of higher socio-economic and educational status and to more frequently undergo screening and biopsy investigation.
Familial prostate cancers appeared to be diagnosed at an earlier stage of disease progression in this study population, possibly as the result of the higher socio-economic status and greater use of screening and investigative procedures amongst patients reporting a positive family history. These features reduce the validity of cross-sectional comparisons of prognostic variables for familial vs sporadic prostate cancer and emphasize the need for further longitudinal prognostic studies.