Improvement in survival rate of patients with acral melanoma observed in the past 22 years in Sendai, Japan.

While the incidence of malignant melanoma is much lower in Japanese than in Caucasians, the commonest site of melanoma in Japanese has been reported to be the acral regions of the limbs. The survival rate for acral and nodular melanoma observed at the Department of Dermatology, Tohoku University Hospital in Sendai, Japan from 1969 to 1990 was reviewed. Among 150 melanoma patients 125 (83%) and 17 (11%) had primary cutaneous melanoma and mucous membrane melanomas, respectively. Frequent sites for cutaneous melanomas were the sole (31%) and subungual regions (15%). Comparison of the stages of plantar melanoma at diagnosis showed that the proportion of stages III and IV decreased after 1980 with a corresponding increase in those with a tumour thickness of less than 4 mm (stage II). Concurrently, the prognosis of plantar melanoma has improved; the 5-year survival rate in each of the three periods 1969-75, 1976-80 and 1981-85 was 21, 70 and 90%, respectively. This was also the case with subungual melanoma. Such improvements in the prognosis are thought to be mainly due to early detection through the growing public awareness of this life-threatening disease. By contrast cases of nodular melanoma increased sharply after 1980. Among these, the high proportion of patients in advanced stages (stages III and IV) remained static even after 1980, with a resultant low 5-year survival rate in the above mentioned periods of 33, 38 and 18%, respectively.