Early response as assessed by anatomic imaging does not predict failure-free survival among patients with Group III rhabdomyosarcoma: A report from the Children’s Oncology Group

Abstract

Background The prognostic significance of response to induction therapy for rhabdomyosarcoma (RMS) by anatomic imaging [computerized tomographic (CT) or magnetic resonance imaging (MRI) scan] is controversial. We previously reported no relationship between early response and failure-free survival (FFS) on Intergroup Rhabdomyosarcoma Study IRS-IV. We repeated the same analysis using a more recent clinical trial as an independent cohort of patients with non-metastatic, initially unresected RMS. Methods A total of 338 patients enrolled in Children’s Oncology Group (COG) study D9803 met the inclusion criteria for this analysis: (1) non-metastatic, initially unresected (Group III); (2) embryonal (ERMS) or alveolar (ARMS) histology; (3) documented protocol week 12 response to induction chemotherapy (excluding progressive disease) based on anatomic imaging (CT/MRI); and (4) documented protocol therapy beyond week 12. Response at week 12 was determined by the treating institution as complete response (CR), partial response (PR), or no response (NR). FFS was estimated using the Kaplan-Meier method and comparisons between patient subsets were made using the log-rank test. Results Overall objective response rate (CR+PR) at week 12 of therapy was 85% and was similar between ERMS and ARMS. FFS was similar among all patients with CR, PR, or NR (p=0.49). Restricting the analysis to either ERMS or ARMS, there was no difference in FFS by response within either histology subset (p=0.89 and p=0.08, respectively). Conclusions These findings provide additional evidence that anatomic imaging to assess early response to therapy among patients with RMS does not predict outcome and has questionable use in tailoring subsequent therapy.

Local Control for Intermediate-Risk Rhabdomyosarcoma: Results From D9803 According to Histology, Group, Site, and Size: A Report From the Children's Oncology Group

“…Anatomic response to chemotherapy, which was given for 12 weeks before definitive radiation on this study, did not correlate with EFS (11). It is possible but very unlikely that a difference specifically in local control may correlate with anatomic response in any subset of patients, although this has been reported in single-institution series (12).…”

Local Failure in Parameningeal Rhabdomyosarcoma Correlates With Poor Response to Induction Chemotherapy

“…Interestingly, a longer duration of induction CT did not increase tumor response. Our results suggest that tumor response occurs quickly during induction therapy and that patients could be reliably assessed as early as week 5, rather than at week 8, 9, or 12 as has been done in prior studies, which may have implications for future RMS trials (6, 10, 11). …”

“…Treatment volumes conformed to COG protocol specifications. A cone down after 36 Gy was used in accordance with the COG RMS protocol guidelines (11). The timing of RT was determined either by protocol or in consultation with the referring doctors.…”

“…Dharmarajan et al (9) found a nearly significant improvement in LF in RMS patients with negative positron emission tomography (PET) imaging after induction CT (3% vs 19%, P =.06), suggesting that response to CT may influence local control (LC) as well. By contrast, separate analyses of 2 Children's Oncology Group (COG) trials have failed to show a correlation between response to induction CT and failure-free survival (FFS) (10, 11). …”

Orbital Rhabdomyosarcoma with a good life prognosis after surgical treatment in a 14-year-old patient

“…Other authors reported [30] no relationship between early response and survival, and that an early response to therapy among patients with rhabdomyosarcoma, does not predict any outcome.…”