Can Higher Doses of Radiation Be Effective for Soft Tissue Sarcoma?

Surgery is often the gold standard and first line of treatment for patients with soft tissue sarcoma, but for some, sarcomas cannot be reached surgically or may involve critical structures that cannot be removed. For those patients not eligible for surgery, definitive radiotherapy is the next best option, but that comes with a caveat as radiation therapy alone doesn’t always give doctors the outcomes they’re looking for.

But what if patients could safely handle higher doses of radiation, ultimately improving their chances of shrinking those soft tissue sarcomas that can’t be surgically removed? A new study is hoping to answer that question. A new type of high-dose radiation therapy, called hypofractionated accelerated radiotherapy dose (HARD), uses a simultaneous integrated boost for unresectable soft tissue sarcomas. This technique delivers stronger doses of radiation in fewer treatments.

“In the initial experience we found that there’s excellent local control,” said Dr. Matthew Mills, a radiation oncology resident at Moffitt Cancer Center and one of the study’s investigators. “Not a single patient failed within the area we treated with radiation. They had no real significant toxicities and the vast majority recovered very quickly by the three-month follow-up.”

Acute toxicity was a primary concern for the study’s investigators. Depending on the area treated, radiotherapy can cause things like increased skin redness and peeling, weakened or stiff joints, and slow wound healing, which can lead to an increased risk of infection.

Matthew Mills, MD from @MoffittNews presents on novel hypofractionated accelerated radiotherapy dose @ASTRO_org tomorrow at 12:45 p.m. #RadOnc #ASTRO22 pic.twitter.com/8HZVOK1U5c

— Moffitt Cancer Center (@MoffittNews) October 25, 2022

In this study, researchers looked at 22 patients, mostly with grade 3 recurrent sarcoma in their lower bodies. Eight of the participants had localized disease while the remaining 14 had evidence of distant metastatic disease.

Interim results of the study were presented last week at the American Society for Radiation Oncology annual meeting. After a 14-month follow-up, there was a 91% limb preservation rate, with only two amputations due to complications after re-irradiation due to infection with intractable pain.  Researchers found acute toxicity in 14 cases (64%) of grade 2 and five cases (23%) of grade 3 skin toxicity only, which completely resolved or healed by a three-month follow-up.

“It was a well-tolerated, effective treatment modality that allows us to deliver a stronger dose of radiation, gives us good control and minimizes side effects,” said Mills. “I think this can be a fantastic option for patients who aren’t eligible for surgery. The hope is that one day this becomes the standard of treatment. We need to continue to evaluate these patients long term and make sure that they continue to tolerate the treatments months and years down the road.”