Disease-specific survival of men with prostate cancer detected during the screening interval: results of the European randomized study of screening for prostate cancer-Rotterdam after 11 years of follow-up.
BACKGROUND
In a screening program, interval cancers are cancers diagnosed between two screening visits.


OBJECTIVE
To assess the disease-specific survival (DSS) of men with prostate cancer (PCa) detected during the screening interval.


DESIGN, SETTING, AND PARTICIPANTS
Within the European Randomized Study of Screening for Prostate Cancer section Rotterdam, 42 376 men identified from population registries (55-74 yr of age) were randomized to a screening or control arm. The median follow-up was 11 yr.


INTERVENTION
Men with prostate-specific antigen ≥ 3.0 ng/ml were recommended to undergo lateralized sextant biopsy. The screening interval was 4 yr.


MEASUREMENTS
The disease-specific mortality of men with interval cancers was compared with that of men with PCa in the control arm; the secondary end point was overall mortality. An independent committee determined the causes of death.


RESULTS AND LIMITATIONS
In the screening arm, 139 men were diagnosed with interval cancer of whom 8 died of the disease. In the control arm, the corresponding numbers were 1149 and 128, respectively. When comparing men with interval cancer to men with PCa in the control arm, no statistically significant difference in disease-specific mortality (hazard ratio [HR]:1.12; 95% confidence interval [CI], 0.53-2.36; p = 0.77) and overall mortality (HR: 0.98; 95% CI, 0.68-1.38; p = 0.90) was found, adjusted for age, prognostic factors, and treatment modality. The follow-up is too limited to address the difference in DSS stratified for screening interval.


CONCLUSIONS
In the setting of population-based PCa screening at 4-yr intervals, the DSS of men with interval cancer seems to be similar to that of men with PCa in the control arm. Given that interval cancers contribute significantly to PCa mortality, further benefit in DSS in the screening arm may be achieved by decreasing the occurrence of interval cancer. However, the balance between mortality reduction and overdiagnosis should be preserved.


TRIAL REGISTRATION
ISRCTN49127736.