Prognostic Factors and Treatment Outcomes of Adult Patients With Rhabdomyosarcoma After Multimodality Treatment

Background: Adults with rhabdomyosarcoma (RMS) have a worse clinical outcome compared to pediatric cases. In the present study, the failure pattern and clinical outcome of adult patients with RMS who received multimodality treatment at our Institution was assessed. Patients and Methods: Data were retrospectively recorded and analyzed from 20 adult patients, aged 19 years or more, who were treated for RMS at our Institution between 2004 and 2015. Disease-free (DFS) and overall (OS) survival after starting treatment were calculated using the Kaplan-Meier method. The relationship of these outcome measures with the following variables was then assessed: Primary site, tumor stage, lymph node involvement, histological subtype, radiotherapy (RT), and duration of chemotherapy. Results: Sixteen patients had localized RMS, and four had metastatic disease. For the whole patient cohort, the 3-year DFS and OS rates were 20%, and 45%, respectively. Patients with alveolar histological subtype had a better 3-year OS than those with other subtypes (p=0.038). The median OS rates for those with localized and metastatic disease were 53.2 (95% confidence interval(CI)=14.7-91.8) months, and 21.7 (95% CI=0-45.7) months, respectively (p=0.047). In patients with localized RMS, those who received RT (n=13) had a better median DFS (24.6 versus 6.0 months, p=0.009) and OS (53.2 versus 11.4 months, p=0.009) than those who did not (n=3). For patients receiving RT, concurrent chemotherapy with vincristine and cyclophosphamide (n=11) was associated with better 3-year DFS (36.4% versus 0%, p< 0.001) and OS (81.8% versus 0%, p< 0.001) compared with RT alone (n=2). Administration of chemotherapy for more than 19 weeks significantly correlated with better 3-year DFS (44% versus 0%, p=0.001) and OS (53.3% versus 0%, p< 0.001) in those with localized RMS. Conclusion: In addition to staging and histological subtype, our results indicate that concurrent chemoradiotherapy and longer duration of chemotherapy were associated with significantly improved DFS and OS in adult patients with localized RMS.