The overall 5-year survival rate is approximately 71%.1
However, for patients with high-risk disease, a group that includes children 10 years of age or older with widespread disease with or without an activating PAX/FOX01 gene fusion, 5-year survival ranges from just 20% to 30% (Cancer Facts & Figures 2020).
“Among patients with metastatic disease, there is a clear difference in overall survival between those who have fusion-positive disease, where the 5-year overall survival is about 19%, and patients with fusion-negative disease,” said Douglas S. Hawkins, MD, chair of the children’s oncology group and professor of pediatrics at the University of Washington, Seattle, and associate chief in the division of hematology/oncology at Seattle Children’s Hospital.
Patients with fusion-negative disease can be further classified into those with multiple metastatic sites, with a 5-year overall survival rate of approximately 45%, and those with a single metastatic site, with a 5-year overall survival rate of 70%, he said in an interview.
“So when we talk about metastatic rhabdomyosarcoma, there actually is a diversity of outcomes, between really bad – those with fusion-positive disease – and not terrible – not great, but not terrible – for a selected group of patients with fusion-negative disease,” Dr. Hawkins said.
The poor prognosis for patients with metastatic fusion-positive disease prompted Dr. Reed and colleagues to rethink the entire approach to advanced cancers.
“If someone has a sarcoma, we know that we need to do surgery and radiation to the area, we know that localized disease does better than metastatic disease, and we generally hit it with some kind of chemotherapy that we call ‘standard of care,’ ” he said in an interview.
This approach is largely effective in some forms of cancer of bone and soft tissues, such as Ewing sarcoma, he notes, which has 5-year survival rates below 20% when treated with surgery and radiation only, but with the addition of chemotherapy has 5-year overall survival rates as high as 80%.
“At other times, with other sarcomas, the cure rate is abysmal, but we still call it standard of care,” Dr. Reed said.
For example, patients with metastatic fusion-positive RMS may have an initial response to chemotherapy, but most will eventually experience relapse and die of the disease.
“With some of the most common treatments, 70% of patients will have their cancers shrink by more than 50%, which is a major response, but the vast majority of them will have a recurrence later on,” Dr. Hawkins said.
He noted that the standard of care for patients with metastatic rhabdomyosarcoma, both with and without the PAX/FOX01 fusion, is chemotherapy, generally with the VAC regimen (vincristine, actinomycin D, and cyclophosphamide), although other agents such as doxorubicin, ifosfamide, etoposide, or irinotecan have also been tried, with little effect on event-free survival or overall survival rates.
A life too brief
Ricky Huff and his family know the course that the disease can take only too well. In 2015, his 5-month-old son, Theo, was diagnosed with metastatic rhabdomyosarcoma and put under the care of Damon Reed at Moffitt.