Interhospital differences in cancer survival: magnitude and trend in 1975-1987 in Osaka, Japan.

This study addresses the disparity in cancer survival rates among hospitals in Osaka, Japan. Using data from the Osaka Cancer Registry, four-year survival rates for stomach cancer patients (n = 8,845) diagnosed in 1976, 1981 and 1986, and lung cancer (n = 9,795) and breast cancer patients (n = 7,377) diagnosed in 1975-77, 1980-82 and 1985-87 were calculated according to four hospital categories (teaching hospitals, large hospitals: 400 + beds excluding teaching hospitals, medium-size hospitals: 150-399 beds, and small hospitals: 20-149 beds). Cox's proportional hazards model was employed with adjustment for sex, age, clinical stage at diagnosis, and treatment status. Stomach and lung cancer patients treated in large, medium-size and small hospitals showed significantly higher risks of death than those treated in teaching hospitals in 1975-87. Interhospital differences in breast cancer survival appeared to increase in 1975-87, whereas those in stomach and lung cancer survivals decreased during the same period.