Objective: To investigate which prognostic factors apply in patients with localized prostate cancer diagnosed after the introduction of prostate-specific antigen (PSA) testing, as comorbidity has significant prognostic value for patients who were diagnosed with localized prostate cancer in the 1970s. Patients and methods Using the Eindhoven Cancer Registry, we assessed a population-based cohort of patients aged < 75 years with localized (T1-T3M0) prostate cancer diagnosed between 1993 and 1995 in a defined area with 2 million inhabitants in the southern Netherlands (n = 894). After a mean follow-up of 2.9 years, overall survival was modelled by Cox regression analyses.
Results: Comorbidity was the most important prognostic factor, especially for those aged < 70 years; at 60 years old, patients with one concomitant disease were twice as likely to die than those with no comorbidity (95% confidence interval, CI, 1.0-4.3), whereas the hazard ratio (HR) was 7.2 (3.1-16.6) for two or more diseases. This was not caused by a reduced use of curative treatment for these patients. At the age of 74 years, comorbidity was no longer a significant prognostic factor. Poor differentiation of the tumour was also an important prognostic factor at all ages; this became increasingly apparent 2 years after diagnosis (HR 3.4, CI 1.5-7.7). Conclusion Comorbidity had a decisive influence on the prognosis for patients with localized prostate cancer. Because this effect was stronger in younger patients the assessment of comorbidity seems most important when evaluating the risk of early death.