Survival and prognostic factors of patients with skin melanoma. A regression-model analysis based on nationwide cancer registry data.

Survival and prognostic factors of skin melanoma patients were studied using a regression analysis of relative survival rates based on nationwide cancer registry data. The material consisted of 4980 cases of melanoma of the skin diagnosed in Finland in 1953 to 1981 and reported to the Finnish Cancer Registry. In the last diagnostic period, 1974 to 1982, the 5-year relative survival rate for male patients was 61.1% and that for female patients 76.6%. The analysis included variables sex, age, stage, year of diagnosis, follow-up year, and site of the tumor. All of them were needed to explain the differences in survival. The patients had the greatest relative risk of dying from skin melanoma during the second year from diagnosis. However, the difference in death risk due to melanoma by stage was most remarkable during the first follow-up year: the risk of patients with nonlocalized disease was over 12 times that of others. The male-female ratio in the risk of dying from skin melanoma was (to a marked extent) attributable to differences in the distributions of stage and site of the tumor. In all site groups males did worse than females but risk ratio varied from 1.15 (trunk) to 1.89 (limbs). The effect of some important prognostic factors on survival could be quantified with ample material and with a method taking into account the competing causes of death. The results suggest a difference either in biological behavior of skin melanoma or in a patient's delay between males and females.