By Celine Zadorsky

Five high-dose radiation treatments targeting uterine cancer rather than the current standard 25 treatments are safe and well-tolerated by patients, a new study published in JAMA Oncology has found.

SPARTACUS (Stereotactic Pelvic Adjuvant Radiation Therapy in Cancers of the Uterus) — a multi-institutional non-randomized controlled trial — looked to assess the feasibility and safety of using a specialized technique called stereotactic body radiation therapy (SBRT) for women with uterine cancer where instead of 25 treatments over five weeks, five treatments can be delivered over 1.5 weeks.

SBRT uses many precise beams of radiation to target tumours or cancerous cells. It uses a higher dose of radiation in a smaller number of treatments. It can be done on a standard linear accelerator, the machine that delivers radiation treatments.

Sixty-one women were enrolled in SPARTACUS at two centres — Sunnybrook Health Sciences Centre and the London Regional Cancer Program (LRCP) at London Health Sciences Centre (LHSC).

“Uterine cancer is a common cancer in women, usually treated with surgical removal followed by radiation and/or chemotherapy to reduce the risk of recurrence,” said Dr. Eric Leung, radiation oncologist at Sunnybrook’s Odette Cancer Centre. “External beam radiation is usually given over five weeks, and that can place a heavy burden on women who have to travel to a radiation centre every day, spend time away from home and work, and incur the financial burden of these factors as well.”

With a median follow-up of nine months, the patients enrolled in SPARTACUS reported an acceptable level of side effects from the radiation that resolved, and also reported a reasonable quality of life during treatment, Dr. Leung said.

“We were interested in examining the toxicity of the higher dose – would it affect the nearby bowels or bladder and place a heavy symptom burden on patients? We were pleased to find that patients reported their symptoms as manageable.”

“This study represents a novel way of treating uterine cancer in a shorter time. It was conducted mainly through the COVID pandemic and gave women a chance to receive treatment in less time with fewer visits to our centres,” said Dr. David D’Souza, radiation oncologist at LHSC and the study co-lead through Lawson Health Research Institute.

Patients will continue to be followed on the study for late side effects and further research is planned to further compare this more convenient schedule to the standard five-week course of radiation.

“This novel treatment could lead to a practice change that places less burden on patients and on the healthcare system,” Dr. Leung said. “Delivering radiation over the course of a week and half rather than over five weeks for patients facing uterine cancer would open up healthcare resources by reducing visits and usage of the linear accelerators.”

Celine Zadorsky works in Communications & External Relations Lawson Health Research Institute.