2018 ASCO: Low-Dose Maintenance Chemotherapy in Rhabdomyosarcoma
A new chemotherapy strategy seems to improve cure rates for children with rhabdomyosarcoma who are at high risk for cancer recurrence. In a randomized phase III clinical trial, adding 6 months of low-dose maintenance chemotherapy after initial treatment increased the 5-year overall survival rate from 73.7% to 86.5%. Children with rhabdomyosarcoma who are alive at 5 years are considered cured, as tumor recurrence is rare.
These findings were presented by Bisogno et al in ASCO’s Plenary Session, which features four studies deemed to have the greatest potential to impact patient care as part of the 2018 ASCO Annual Meeting (Abstract LBA2).
“We have been treating rhabdomyosarcoma the same way for more than 30 years, and although different approaches have been tried, this is the first randomized trial in rhabdomyosarcoma to show improved outcomes. By using existing medicines in new ways, we are establishing a new standard of care and, most importantly, we’re helping children and young adults with this rare cancer live longer, with less risk of their cancer returning,” said lead study author Gianni Bisogno, MD, PhD, Professor at the University Hospital of Padova in Italy and Chair of the European Paediatric Soft Tissue Sarcoma Study Group.
About Rhabdomyosarcoma
Rhabdomyosarcoma originates in the muscle tissue and can occur in any part of the body, but it is most often found in the head, neck, pelvis, and abdomen. Rhabdomyosarcoma is rare, accounting for 4% of all childhood cancers (about 350 children are diagnosed with this cancer each year in the United States).
The prognosis for rhabdomyosarcoma is generally good—80% of children can be cured with modern treatment, which includes high-dose chemotherapy, radiation, and surgery. However, among children who have metastasis at diagnosis or a recurrence after initial treatment, just 20% to 30% can be cured.
About the Study
This trial enrolled patients 6 months to 21 years of age who were considered at high risk for recurrence due to having large tumors located in a part of the body that is difficult to treat (eg, the head). After completing the standard initial treatment, 371 patients (79% of whom were up to 10 years old) were randomly assigned either to stop treatment (the former standard of care) or receive 6 months of maintenance therapy with low doses of intravenous vinorelbine and oral cyclophosphamide.
Key Findings
At 5 years from diagnosis, the disease-free survival rate was 68.8% in the standard treatment group vs 77.6% in the maintenance group, and overall survival rates were 73.7% vs 86.5%, respectively.
The most common side effect in the maintenance group was low blood cell count, although it was usually mild. Febrile neutropenia occurred in 25% of patients. Infection rates were much lower with maintenance treatment than after initial standard chemotherapy, and neurologic side effects resolved after treatment ended. However, as with most types of chemotherapy, long-term side effects are still possible, and patients will continue to be monitored.
Next Steps
The findings of this trial have already changed the standard of care in Europe, where investigators shared the results with soft-tissue sarcoma study group institutions in 14 countries. As the standard of care is somewhat different in the United States, there is a need for further study to understand how to integrate maintenance therapy into existing treatment protocols.
Commentary
“By keeping the pressure on this cancer longer with maintenance therapy, we are giving patients two wins—we are boosting cure rates by preventing relapses and doing so with few serious side effects. After 3 decades of research, this finding goes to show that we will continue innovating treatment, no matter how long it takes,” said ASCO Expert Warren Chow, MD.
This study received funding from Fondazione Città della Speranza, Italy.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
