Malignant melanoma of the vulva and vagina. Trends in incidence, age distribution, and long-term survival among 245 consecutive cases in Sweden 1960-1984.

BACKGROUND

Malignant melanomas of the vulva and vagina are rare tumors located in areas of the body not exposed to ultraviolet radiation. Investigations comprising large consecutive population-based series of patients with these diseases have not been published previously, to the knowledge of the authors.

METHODS

Trends in incidence, age distribution, and prognosis were investigated among 219 consecutive cases of malignant melanoma of the vulva and 26 cases in the vagina, reported to the Swedish National Cancer Registry and representing virtually all primary tumors of that kind in Sweden during a 25-year period, 1960-1984.

RESULTS

On average, 75% of the patients with vulvar melanoma and 73% with vaginal melanoma were older than 60 years of age. The mean age increased slightly but not significantly during the period. The age-standardized incidence of vulvar melanoma decreased from 0.27 to 0.14 per 100,000 Swedish women, or by 3% per year. The observed 5-year survival rate of patients with vulvar melanoma was 35%, and the relative survival rate was 47%. The observed and relative survival rates at 10 years were 23% and 44%, respectively. Observed and relative survival rates among patients with vaginal melanoma after 5 years were 13% and 18%, respectively.

CONCLUSIONS

Accordingly, there was a decreasing incidence of vulvar and vaginal melanoma over the observed 25 years. This is in contrast to the trends in incidence for cutaneous melanomas in Sweden, which, during the same time period, increased almost 6% per year.