Background: Survival of cancer patients has been measured only in some limited areas in Japan until recently. The purpose of the present study was to collect data of fairly high quality on the population-based cancer registries and to estimate relative 5-year survival of cancer patients in Japan.
Methods: We requested 11 population-based cancer registries within the research group to submit individual data of the patients diagnosed from 1993 to 1996, together with the prognosis after 5 years, to the collaborative study secretariat. Ten population-based cancer registries (Miyagi, Yamagata, Niigata, Chiba, Kanagawa, Fukui, Aichi, Osaka, Tottori and Nagasaki) then accepted data submission (373,000 data). Among 10 registries, only 7 registries met the required standards for the quality of registration data and prognosis investigation. The relative 5-year survival calculated by pooling 279,000 data from seven registries was taken as the national estimate of that of cancer patients in Japan.
Results: The relative 5-year survival was 53.6% for all cancers (males: 49.2%, females: 59.4%); the survivals of stomach, large bowel, prostate and kidney cancer patients were from 62 to 68%; those of breast, uterus, larynx, skin, testis, bladder and thyroid cancer patients were from 74 to 92%; those of liver, gall bladder and bile duct, pancreas and lung cancer patients ranged from 6 to 23%.
Conclusion: On the basis of the data from seven population-based cancer registries in Japan, we calculated the relative 5-year survival of cancer patients diagnosed from 1993 to 1996 for the first time.