No improvement in survival from melanoma diagnosed from 1973 to 1984

While the incidence and mortality of melanoma has increased dramatically during the last few decades, survival rates, based on the case-fatality ratio, have apparently improved. Efforts at early detection have probably been effective in the discovery of lesions at a curable stage. However, the effects of lead-time bias need to be accounted for in order to understand the contribution of early detection to the increased incidence. This can best be done by appropriately controlling for depth of the tumour or a surrogate of depth, at diagnosis.

A survival analysis was conducted for 3197 Connecticut residents newly diagnosed with invasive melanoma between 1973 and 1984. Five prognostic variables were evaluated: sex, age at diagnosis, anatomical site, histological type, and year of diagnosis.

As expected, women and the young had better survival than men and the elderly. Melanomas located on the trunk had poorer prognosis than those on other sites. The survival experience by histological type was significantly different; lentigo maligna melanoma and superficial spreading melanoma had the best survival and nodular melanomas the poorest, while 'other' and unclassifiable melanomas had intermediate survival. When survival by period of diagnosis was controlled by other variables, which included surrogates for disease stage, there was no improvement in survival over time.

These data do not imply that early diagnosis and treatment are ineffective; rather, that within stages of disease, survival improvements did not occur during the period 1973-1984.