Soft tissue leiomyosarcoma. A population-based epidemiologic and prognostic study of 48 patients, including cellular DNA content

BACKGROUND. Leiomyosarcoma of soft tissue is a rare tumor. There are different opinions regarding epidemiology and prognosis. METHODS. Epidemiology and prognosis were analyzed in a consecutive, population-based series of 48 patients with subcutaneous and deep-seated leiomyosarcoma in the extremities and trunk wall with a complete follow-up of a minimum of 3 years. Cutaneous tumors were not included. RESULTS. The annual incidence was 0.13/10(5). The ratio of men to women was 1.2, and the median age was 65 years. The thigh was the most common location. Almost half of the tumors were subcutaneous. The median tumor size was 6 cm (range, 1-25 cm). All patients were treated with surgery, and in 19 cases it was combined with adjuvant radiation therapy or chemotherapy. The cumulative 5-year survival rate was 64%. Multivariate analysis indicated that age of 60 years or greater (relative risk [RR] = 8) and intratumoral vascular invasion (RR = 4) were independent risk factors for death resulting from tumor. DNA aneuploidy (RR = 4) and tumor necrosis (RR = 3) were associated with poor prognosis, but did not reach statistic significance. CONCLUSIONS. Advanced age, vascular invasion, and DNA aneuploidy could be used to identify prognostic subgroups.