Local control and outcome in children with localized vaginal rhabdomyosarcoma: a report from the Soft Tissue Sarcoma committee of the Children's Oncology Group

Abstract

Background: The local control approach for girls with non-resected vaginal rhabdomyosarcoma (RMS) enrolled onto Intergroup RMS Study Group (IRSG)/Children's Oncology Group (COG) studies has differed from that used at other primary sites by delaying or eliminating radiotherapy (RT) based on response achieved with chemotherapy and delayed primary resection.

Procedures: We reviewed locoregional treatment and outcome for patients with localized RMS of the vagina on the two most recent COG low-risk RMS studies.

Results: Forty-one patients with localized vaginal RMS were enrolled: 25 onto D9602 and 16 onto Subset 2 of ARST0331. Only four of the 39 with non-resected tumors received RT. The 5-year cumulative incidence of local recurrence was 26% on D9602, and the 2-year cumulative incidence of local recurrence was 43% on ARST0331. Increased local failure rates appeared to correlate with chemotherapy regimens that incorporated lower cumulative doses of cyclophosphamide. Estimated 5-year and 2-year failure free survival rates were 70% (95% CI: 46%, 84%) on D9602 and 42% (95% CI: 11%, 70%) on ARST0331, respectively.

Conclusions: To prevent local recurrence, we recommend a local control approach for patients with non-resected RMS of the vagina that is similar to that used for other primary sites and includes RT. We recognize that potential long-term effects of RT are sometimes unacceptable, especially for children less than 24 months of age. However, when making the decision to eliminate RT, the risk of local recurrence must be considered especially when using a chemotherapy regimen with a total cumulative cyclophosphamide dose of ≤ 4.8 g/m².

Conflict of interest statement

CONFLICT OF INTEREST STATEMENTM

AP is a consultant for ZIOPHARM. The other authors have no conflicts of interest to disclose.

Copyright © 2011 Wiley-Liss, Inc.

Figures

Fig. 1

Local control approach and outcome for patients with Group IIA and III N0 vaginal RMS on D9602 (n=23: median follow-up 5.6 years) (A) and for patients with Group III N0 vaginal RMS on ARST0331 (n=14: median follow-up 1 year) (B). For (A): CR, complete response; PR, partial response (decrease in the product of the maximum perpendicular diameters of the tumor of ≥ 50%); SD, stable disease (decrease in the product of the maximum perpendicular diameters of the tumor of < 50% and not qualifying as progressive disease); PD, progressive disease (increase of ≥ 25% in the product of the maximum perpendicular diameters of the tumor); Neg, negative for RMS; Pos, positive for RMS; NED, no evidence of disease. For (B): Abbreviations as in (A) except; PR, partial response (decrease in tumor volume of ≥ 64%); SD, stable disease (decrease in tumor volume < 64% and not qualifying as progressive disease); PD, progressive disease (increase in tumor volume ≥ 40%). *Timing of the response assessment varied based on the timing of the definitive biopsy or delayed primary resection. **Uncertain based on available records.

Fig. 2

FFS and OS for the 25 patients with vaginal RMS on D9602.

Fig. 3

FFS and OS for the 16 patients with Group III vaginal RMS on ARST0331.