A Retrospective Analysis of Adult Head and Neck Rhabdomyosarcoma (HN RMS) from 1984-2017.

e18089 Background: Head and Neck Rhabdomyosarcoma (HN RMS) in adults is an aggressive and challenging approach to managing malignancy. Our goal was to describe the presentation, treatment, outcomes, patterns of failure, and prognostic factors of HN RMS patients treated at our institution between 1984 and 2017. Methods: A retrospective review of adult ( > 16 years) HN RMS patients registered in the multidisciplinary Sarcoma Clinic who received majority of their treatment at our institution was performed. Survival analyses were performed using the Kaplan-Meier Method. Prognostic variables including age, anatomic location, histologic subtype, radiation, and TNM stage were analyzed in univariate (UVA) Cox analyses. Results: Fifty-eight patients were identified, with a median age of 32 years (ranged 16 to 81); 26 were male. Seventy-six percent of tumors (n = 45) were parameningeal and 88% (n = 51) were > 5cm. Fifty percent of patients (n = 29) had clinical node positive disease and 15% (n = 9) had distant metastases at the time of diagnosis. Local treatment consisted of surgery and radiotherapy (RT) versus RT alone in 9% (n = 5), and 91% (n = 53) patients respectively; with 76% (n = 45) receiving chemotherapy. Local and regional control at 5 years was 64% and 73%, respectively. With a median follow-up of 18 months, 5-year Overall Survival (OS) was 34% (95% CI: 20%-48%) and 29% (95% CI: 17%-42%) for non-metastatic and metastatic patients, respectively. Patterns of failure were further analyzed in 49 non-metastatic patients. Sixty-seven percent (n = 30) patients relapsed, with median time to progression of 15 months. Median time to distant failure was 20 months. On UVA, concurrent chemotherapy (HR 2.3, p = 0.029) and tumor size (HR 2.6, p = 0.01) were associated with worse survival. Distant metastasis was the predominant mode of first failure (n = 16, 33%). This population was also enriched for patients with metastases in unusual locations, including testes (n = 2), breasts (n = 2), leptomeninges (n = 12), and bone marrow (n = 9). Conclusions: Adult HN RMS of the head and neck is an aggressive malignancy with an unfavorable prognosis, despite intensive treatment, but is potentially curable, particularly with modern radiotherapy techniques and chemotherapy.