The Prognostic Significance of Early Tumor Volume Change in Rhabdomyosarcoma

Patrick Debs; Rohini Bhatia; Jacqueline Kruglyakova; Suqi Ke; Chen Hu; Matthew Ladra; Christine A Pratilas; Shivani Ahlawat; Laura M Fayad; Sahaja Acharya

doi:10.1016/j.adro.2024.101561

The Prognostic Significance of Early Tumor Volume Change in Rhabdomyosarcoma

Adv Radiat Oncol. 2024 Jun 29;9(8):101561. doi: 10.1016/j.adro.2024.101561. eCollection 2024 Aug.

Authors

Affiliations

¹ The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland.
² Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland.
³ Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
⁴ Bloomberg School of Public Health, Division of Biostatistics, Johns Hopkins University School of Medicine, Baltimore, Maryland.
⁵ Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Abstract

Purpose: To describe early tumor volume change in patients with rhabdomyosarcoma (RMS) and investigate its association with overall survival (OS) and local failure.

Methods and materials: This retrospective study included patients who received diagnoses of group III/IV RMS with available computed tomography and/or magnetic resonance imaging scans at 2 time points: (1) pretherapy and (2) early therapy (acquired during weeks 8-12 of chemotherapy). Relative volumetric change (RVC) was calculated as the percentage of (early therapy - pretherapy volume) / (pretherapy volume). Cox regression was used to identify variables associated with OS. The Fine-Gray model was used to estimate local failure.

Results: Eligible patients (n = 55) had the following characteristics: median age at diagnosis, 9.6 years and median follow-up, 30.4 months. Most tumors were alveolar (61.8%), followed by embryonal (34.6%) and spindle cell/sclerosing (4%). The median RVC was -86.4% with larger decreases observed in alveolar versus nonalveolar RMS (-89.4% vs -69.8%, P = .043). For embryonal and spindle cell/sclerosing RMS, all of which were FOXO1 fusion negative, RVC was independently associated with OS (hazard ratio for every 50% reduction in RVC [HR_RVC], 0.5; 95% CI, 0.26-0.96; P = .037) and local failure (HR_RVC, 0.57; 95% CI, 0.33-0.99; P = .049). The predominant pattern of failure in embryonal and spindle cell/sclerosing RMS was local, and most were group III.

Conclusions: There was a greater reduction in tumor volume in alveolar versus nonalveolar RMS. Early tumor volume reduction was associated with OS and local failure in embryonal or spindle cell/sclerosing RMS, all of which were confirmed FOXO1 fusion negative and had higher incidence of local compared with distant failures.