Life expectancy estimates as a key factor in over-treatment: the case of prostate cancer.

Objective: To estimate the magnitude of over-diagnosis and of potential and actual over-treatment regarding prostate cancer, taking comorbidities into account.

Materials And Methods: We used a sample collected by the French cancer registries of 1840 cases (T1: 583; T2: 1257) diagnosed in 2001. The proportion of over-diagnosed and over-treated patients was estimated by comparing life expectancy (LE), including or not comorbidities, with natural LE with cancer, using several assumptions from the literature. We distinguished potential and actual over-treatment according to the treatment that patients actually received.

Results: Among patients with T1 tumors the proportion of potential over-treatment using LE adjusted for comorbidity varied from 29.5% to 53.5%, using LE adjusted on comorbidities, and varied from 9.3% to 22.2% regarding actual over-treatment. Between 7.7% and 24.4% of patient's receiving a radical prostatectomy, and between 30.8% and 62.5% of those receiving radiotherapy, were over-treated. Among patients with T2 tumors, the proportions of potential and actual over-treatment were 0.9% and 2.0%. Two per cent of patients receiving a radical prostatectomy and 4.9% of those receiving radiotherapy were over-treated. Comorbidities dramatically increased these proportions to nearly 100% of patients, with more than two comorbidities being potentially over-treated and around 33% actually over-treated.

Conclusions: According to the French incidence, 3200-4800 French patients may be over-treated, among whom a large proportion of patients had comorbidities. The real issue is to offer the most appropriate treatment to people with low-grade tumors and comorbidities.