Extremity soft tissue sarcoma with multiple primary malignancies – Characteristics and outcome

BackgroundUnderstanding the incidence and characteristics of multiple primary malignancies (MPM) has implications for guiding appropriate treatment and surveillance of extremity soft tissue sarcoma (STS).ObjectivesWe sought to examine the incidence of MPM in STS (MPM-STS), and compare their clinicopathologic characteristics and survival to those with STS only.Methods585 patients who underwent surgery for extremity STS were reviewed. Logistic regression analyses to identify factors contributing to the development of MPMs and a 1:2 matched case–control analysis to compare survival outcome were performed.ResultsOf the 585 patients analyzed, 34 (6%) with MPM were identified. On univariate logistic regression analysis, older age (>49 years) at STS diagnosis (p = 0.008) and histologic types of undifferentiated pleomorphic sarcoma or myxofibrosarcoma (p = 0.033) were significant. In multivariate analysis, only older age at STS diagnosis remained significant (OR = 2.5, p = 0.029). Cancer-specific survival of the MPM-STS group was significantly lower than that of the STS-only group (p = 0.031). However, there was no significant difference in STS-specific survival between the two groups (p = 0.208).ConclusionOur study suggests that MPM is not uncommon in extremity STS and older age at STS diagnosis is associated with risk of MPM. Prognosis of STS in the MPM-STS group seems similar to that of the STS-only group.