In a study reported in the Journal of Clinical Oncology, Walterhouse et al found that age ≥ 10 years at diagnosis and tumor size > 5 cm are adverse prognostic features in localized paratesticular rhabdomyosarcoma.
The study was a pooled analysis of data from North American and European cooperative groups, assessing the effect of 9 demographic variables and 4 treatment modalities on event-free survival and overall survival in 12 cooperative group studies. A total of 842 patients with localized paratesticular rhabdomyosarcoma enrolled from 1988 to 2013 were included in the analysis.
Factors Affecting Prognosis
Patients aged ≥ 10 years at diagnosis were more likely vs younger patients to have tumors that were > 5 cm, enlarged nodes (N1), or pathologically involved nodes (all P ≤ .05). With a median follow-up of 7.5 years, estimates for 5-year event-free survival and overall survival among all patients were 87.7% and 94.8%.
Cooperative group, era of enrollment, age category, tumor size, Intergroup Rhabdomyosarcoma Study group, and T stage were all significantly associated with event-free survival (all P ≤ .05). Surgical assessment of regional nodes (performed in 23.5% of patients, usually those aged ≥ 10 years or with suspicious or N1 nodes) was the only treatment variable associated with improved event-free survival on univariate and multivariate analyses (P ≤ .05 each) in patients aged ≥ 1 year.
In proportional hazards regression multivariate models, era of enrollment, age (hazard ratio [HR] = 0.37, P < .001, for 1–9 vs ≥ 10 years), tumor size (HR = 2.42, P < .001, for > 5 vs ≤ 5 cm), and surgical assessment of regional nodes were significantly associated with event-free survival and era of enrollment, age (HR = 0.31, P < .001, for 1–9 years vs ≥10 years), tumor size (HR = 3.60, P = .001, for >5 vs ≤ 5 cm), and histology were significantly associated with overall survival.
The investigators concluded, “Localized [paratesticular rhabdomyosarcoma] has a favorable prognosis. Age ≥ 10 years at diagnosis and tumor size larger than 5 cm are unfavorable prognostic features. Surgical assessment of regional nodes is important in patients aged ≥ 10 years and in those with N1 nodes as it affects [event-free survival].”
The study was supported by grants from the National Cancer Institute, St Baldrick’s Foundation, and a grant from the WWWW (QuadW) Foundation to the Children’s Oncology Group.
David O. Walterhouse, MD, of the Ann & Robert H. Lurie Children’s Hospital of Chicago, is the corresponding author for the Journal of Clinical Oncology article.