Trends in net survival for prostate cancer in Japan, 2000-14 (CONCORD-3)

We aimed at assessing 15-year trends in 5-year net survival for men diagnosed with prostate cancer during 2000-2014 and registered by 16 Japanese regional population-based cancer registries included in the CONCORD-3 study.

We included data on adult men (15-99 years) diagnosed with prostate cancer during 2000-2014 and followed-up to 31 December 2014. We grouped patients into five age groups (15-54, 55-64, 65-74, 75-84, and 85-99 years) and four morphology groups according to the ICD-O-3 classification (epithelial, neuroendocrine, other specified morphologies, and malignant neoplasm, not otherwise specified). We grouped patients by stage at diagnosis into localized, regional, and advanced disease. We estimated 5-year net survival by age group, morphological subtype and stage using the Pohar Perme estimator, correcting for background mortality. All-ages estimates were standardized with the International Cancer Survival Standard weights.

Age-standardized 5-year net survival increased over time, from 85.9% in 2000-2004 to 93.0% in 2010-2014. Survival was higher than 90% for epithelial tumors, and for localized and regional disease. Five-year net survival for patients with distant metastasis was poor at 47.3% (95% CI. 39.4-55.1%) during 2010-2014.

The improvement in survival for prostate cancer may be due to the high and increasing proportion of patients with localized disease and with epithelial tumors, for which 5-year survival approaches 100%. A comprehensive analysis of long-term survival over a longer period of time would be essential to investigate further the factors contributing to the increasing trend in survival.