2507 - Clinical Features and Treatment Outcomes of Pediatric Abdominal and Pelvic Rhabdomyosarcoma
Presenter(s)
Y. Wang1, S. Li2, M. Jiang3, M. Lu4, and Y. Xie2; 1Department of Radiation Oncology, Chongqing University Cancer Hospital, Chongqing, China, chongqing, Chongqing, China, 2Department of Radiation Oncology,Chongqing University Cancer Hospital, Chongqing, China, 3Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, shanghai, China, 4Department of Radiation Oncology, Chongqing University Cancer Hospital, chongqing, China
Purpose/Objective(s): This study analyzed clinical features and treatment outcomes observed in Children with abdominal or pelvic Rhabdomyosarcoma (RMS) in 2 institutions in China between 2011 and 2022.
Materials/Methods: Patients diagnosed with RMS originating from the abdominal and pelvic cavity were analyzed, excluding those derived from the genitourinary system, biliary tract, and the abdominal or pelvic walls. The first line treatment for all these patients included chemotherapy, surgical resection, and radiotherapy. Overall survival (OS) were analyzed using the Kaplan-Meier method.
Results: In total, 76 patients (44 male; 32 female) were included in the analysis. The median age at diagnosis was 48.5 months (range, 3-177 months). Patients had embryonal RMS (n=66), alveolar RMS (n=6), not otherwise specified RMS (n=3), or pleomorphic RMS (n=1). The majority of patients presented with a large primary tumor > 5cm (n=62), T2 primary tumor (n=52). Sixteen patients (21.1%) had regional lymph node metastasis, while the N stage was unknown for another 16 patients. Twenty-one patients (27.6%) had M1 disease. IRS staging was I for 2 patients, II for 10, III for 34, IV for 25, and was unknown in 5 patients. Median follow-up of surviving patients was 57 months. The median survival was not reached. The 5-year OS rate of all patients was 85.8 ± 4.6%. The 5-year OS was related significantly to N stage (N0, 91.0% ± 5.2% vs. N1, 63.3% ± 13.8% vs. unknown N stage, 93.8% ± 6.1% [P = 0.002]), and M stage (M0, 91.3% ± 4.2% vs. M1, 69.4% ± 13.0% [P = 0.016]). Three out of the 6 patients (50.0%) who were aged 10 years or older died, while 9 out of the 70 (12.9%) patients who were younger than 10 years old died. No deaths occurred among patients with IRS-I or those with unknown IRS staging. In the IRS-II group, one patient died of disease progression at 66 months. This patient had regional lymph node metastasis at the time of initial diagnosis. The 5-year OS rates were 85.8% ± 6.8% for IRS-III patients, and 75.6% ± 10.3% for IRS-IV patients.
Conclusion: Despite multimodal treatment approaches, the prognosis of rhabdomyosarcoma remains relatively poor. Regional lymph node metastasis and distant metastasis are strong indicators of poor outcome. For these patients, intensification of treatment may be considered.