According to MedPage Today, a phase III study showed that 6 additional months of chemotherapy for maintenance led to a sizable increase in the 5-year overall survival rate for those who are diagnosed with high-risk pediatric rhabdomyosarcoma. To be exact, the additional 6 months of treatment showed a 13% increase in the survival rate.
Rhabdomyosarcoma is a rare tumor that mainly develops in children. In pediatric patients with rhabdomyosarcoma, cancer cells look like immature, young muscle cells. The cancer forms in the soft tissue and usually starts in the head and neck area, urinary system, reproductive system, or arms and legs. Rhabdomyosarcoma has the potential to spread to other parts of the body and accounts for roughly 3% of childhood cancers. To learn more about the disease, click here.
To get into the specifics of this study, called RMS2005 Maintenance, it has been shown that additional low-dose chemotherapy (vinorelbine/cyclophosphamide) increased the 5-year survival rate in patients from 73.7% to a noteworthy 86.5%. These findings were reported by the University Hospital of Padova, Italy and announced at the American Society of Clinical Oncology (ASCO) annual meeting.
The doctor who reported the findings, Gianni Bisogno, explained the implications from the study: “At the end of this long, not-easy study, we concluded that maintenance is an effective and well-tolerated treatment for children with high-risk rhabdomyosarcoma.”
“And our group decided this is the new standard treatment for patients,” Bisogno declared.
Because recurrences of pediatric rhabdomyosarcoma is rare, the 5 year survival mark is considered to be as good as cured. This technically means that the new discovery can lead to more and more pediatric patients being cured of rhabdomyosarcoma.
However, there are still a few hurdles to cross before this becomes a worldwide standard of treatment.
“These results will need to be tested in the United States with U.S.-based protocols before becoming standard of care,” said Dr. Warren Chow.
Because healthcare standards and applicability vary across countries, and especially are different in the United States, specialists are still uncertain about the future of the treatment in the U.S.
Dr. Julia Glade Bender of New York-Presbyterian Columbia University Medical Center in New York City admits “We use a different backbone [in the U.S.].”
Therapy differs in the U.S.; for example, standard of care treatment for patients in the U.S. uses cyclophosphamide and not ifosfamide, which was used in the study. Additionally, a few patients participating in the trial were given doxorubicin, a treatment that is not used in the United States anymore.
Adding to the differences, protocol for pediatric rhabdomyosarcoma in the U.S. has already changed treatment for the cancer to a longer-than-standard time. The European Paediatric Soft Tissue Sarcoma Study Group has a standard treatment time of 27 weeks, while the U.S. took the lead from the Children’s Oncology Group to have treatment last for 42 weeks.
The maintenance therapy discussed in this study lasts for 51 weeks.
“It begs the question of whether this is really maintenance therapy or just a longer duration of therapy,” said Dr. Bender.
Moreover, it is hard to translate the measure of risk in patients with the cancer from Europe to the U.S. What might be considered high risk in Europe may be intermediate risk in the States.
Dr. Chow added another point to the matter, concerning age. “We’ll need to determine if these results are applicable to patients older than 21 years of age, who are considered high risk based solely on their age,” said Chow.
With all these overseas limitations, this discovery is still something to take a close look at. Notably, this is the first time in a long time there has been an advancement in this field.
Dr. Chow added, “even with these caveats, this is the first significant treatment advance in this rare cancer in more than 30 years.” This is huge.
After all, this trial is currently “only the third positive randomized study to be reported in pediatric rhabdomyosarcoma,” said Dr. Douglas Hawkins, Seattle Children’s Hospital. That means this is the third out of 20 randomized trials of rhabdomyosarcoma that has been significant since 1972.
The trial was carried out from 2006-2016 and tracked 670 patients diagnosed with high-risk rhabdomyosarcoma, according to European standards. In the first 6 to 8 months of the trial, pediatric patients were given standard chemotherapy treatment plus radiotherapy and surgery.
In the next part of the trial, researchers singled out 371 participants who showed no sign of the disease after initial treatment to either stop treatment entirely (control), or continue low-dose maintenance of chemotherapy for 6 months.
At the 5-year mark, 77.6% in the group that continued with maintenance therapy were cancer-free compared to a notable 69.8% of those in the control group.
Still, experts think it is possible that this could be due to extended treatment rather than maintenance.
“One can imagine that we could compare these two strategies to try to tease out whether it’s really the duration of therapy rather than maintenance itself that led to the improved overall survival in the EpSSG study,” said Dr. Hawkins.
Whatever it was, it worked. Hopefully in the future, researchers will be able to find a way to cross the overseas barriers and bring this development into fruition in the United States.