In a new study, researchers at The University of Texas MD Anderson Cancer Center in Houston demonstrated that a shorter course of radiation therapy in the preoperative setting yields comparable results for patients with non-metastatic soft tissue sarcoma (STS). The researchers demonstrated that it is possible to maintain tumor control and risk for major wound healing in patients with STS when treated with 3 weeks of hypofractionated radiation therapy as opposed to the 5-week regimen that is the standard of care.
Results from the single, non-randomized, Phase II study are published in The Lancet Oncology (2022; doi.org/10.1016/S1470-2045(22)00638-6). The study was led by B. Ashleigh Guadagnolo, MD, MPH, Professor of Radiation Oncology at MD Anderson, who presented the results at the 2022 American Society for Radiation Oncology annual meeting.
In the new study, participants received daily doses of radiation therapy that were stronger and given over fewer days, yet realized similar outcomes, such as 31 percent of patients developing major wound complications within 120 days of surgery and local tumor control of 93 percent after 2 years. An STS is any one of a group of rare, heterogeneous diseases with 50 histological subtypes. It is diagnosed in approximately 13,500 individuals and takes the lives of around 5,100 people annually in the U.S., according to the American Cancer Society.
Sarcomas can occur in the bones or soft tissues, including the arms, legs, or superficial trunk soft tissues. The most common types of STS are undifferentiated pleomorphic sarcomas and liposarcomas. Patients with non-metastatic STS are at increased risk of wound-healing complications after surgery and have an increased risk of readmission for further wound management, including additional surgery.
Study Details
The research included 120 patients with previously untreated non-metastatic STS in the extremity or superficial trunk. Lower extremity tumors accounted for 65 percent of patients' sarcomas, upper extremity tumors were 17 percent, and the trunk 18 percent. The patients received 15 daily fractions of 2.85 Gray (Gy), totaling 42.75 Gy over 3 weeks instead of the standard dose of 50 Gy in 25 daily fractions over 5 weeks. Surgery followed 4-8 weeks post-radiation therapy.
Major wound complications were defined in the study as those requiring secondary operations for wound treatment under general or regional anesthesia, readmission to the hospital for wound care, invasive procedures for wound care, deep wound packing to an area of wound measuring at least 2 cm in length, prolonged dressing changes, repeat surgery for revision of a split-thickness skin graft, or wet dressings for longer than 4 weeks. In terms of safety, no patients in the study experienced a serious adverse event of Grade 3 acute skin toxicity.
With safety and effectiveness demonstrated, future analyses of results from the study will focus on topics such as long-term side effects and oncological and functional outcomes using the hypofractionated regimen, according to the researchers.
Reducing treatment time by 2 weeks, meanwhile, may improve access to care for patients, especially those who must travel to receive care at a sarcoma specialty center, which research shows results in better survival rates and outcomes, noted Guadagnolo, who recently shared additional insight into the study with Oncology Times.
Oncology Times: What inspired you to investigate this research question?
Guadagnolo: "We wanted to investigate whether preoperative radiation therapy could be delivered safely and effectively in a shorter time period while maintaining the safety and efficacy of the treatment. We were hoping to determine that effective treatment could be given in a way that was more convenient and less disruptive for patients with soft tissue sarcoma.
"Studies have shown that patients with soft tissue sarcoma have better outcomes when they are treated at a center that has sarcoma specialty care expertise among practitioners, so identification of a shorter duration of treatment would help patients who may face barriers to care (e.g., distance, cost of travel) receive sarcoma treatment at a sarcoma specialty center."
Oncology Times: Were there any unexpected results in your study?
Guadagnolo: "There were really not any surprises. We expected this regimen to be safe and effective, but we needed to do the study in a rigorous way to show that."
Oncology Times: Is there anything in the results others might get wrong?
Guadagnolo: "The long-term outcomes data are not available yet. Patients should be counseled that, while the safety in the short term has been demonstrated by this study, longer follow-up is needed to speak to the long-term outcomes such as lymphedema and limb function."
Oncology Times: What are potential clinical research implications?
Guadagnolo: "Given the importance of specialized care for the management of soft tissue sarcomas, this shorter radiation regimen may facilitate ease of access for patients seeking care at a sarcoma specialty center."
Oncology Times: What further research needs to be done on this topic?
Guadagnolo: "We are collecting data on long-term follow-up for patients on this study and those data will help inform us as to whether the long-term limb function, mobility, and lymphedema outcomes are similar to the longer radiation regimen that has been the standard. There are two other similar trials-one at Mayo Clinic and one at the Netherlands Cancer Institute-on a 3-week course of preoperative radiation therapy for soft tissue sarcoma. Those results will be important for further evaluating the use of a shorter 3-week course of radiation therapy for these patients."
Chuck Holt is a contributing writer.
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