Baseline Characteristics, Prognostic Factors, and Treatment Outcomes for Adult Patients With Rhabdomyosarcoma (RMS).

Background: Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood, while in adults it is one of the rarer tumors. Its prognosis is better in children with current treatment modalities; however, it carries poorer prognosis in adults. Recent data on adult RMS is scarce from our part of world. We report outcomes of adult patients with RMS, and with 40 patients; it is the first study to publish such a large data from Pakistan.

Methods: This was a retrospective study that included 64 adult patients aged 18 years and older. After data extraction and scrutiny, a total of 40 patients were segregated with diagnosis of RMS of various varieties who were treated and followed up subsequently. International Business Machines (IBM) Statistical Package for Social Sciences (SPSS), version 26 (IBM Corp., Armonk, NY) was used to evaluate all of the gathered data.

Results: Embryonal RMS (ERMS) was the most common subtype. Factors favoring better overall survival (OS) at 5 years were absence of nodal and distal metastases, treatment with surgery, margin negative resection, and absence of residual disease on postoperative imaging. Adjuvant radiation therapy (XRT) for positive resection margins as well as for residual disease on postoperative imaging also favored better OS at 5 years. Chemotherapy did impart a trend towards better OS; however, it was not significant. Histopathologic subtype and tumor size did not have any significant impact on outcomes. Median progression free survival (PFS) was 11 months and median OS was 15 months.

Conclusions: Adult RMS is a rare disease entity with widely heterogeneous clinical picture and poorer outcomes as compared to the disease of childhood and adolescence. Further prospective studies with larger sample size are required to establish role of patient, disease, and treatment-related factors affecting outcomes in our population.