Single-fraction radiation therapy as effective as multiple-fraction radiation therapy for palliation of bone metastases

Bone metastases are a common manifestation of distant spread of disease, occurring most frequently with prostate, breast and lung cancers. Of these patients, two-thirds develop bone metastases to the spine, pelvis or extremities. Radiation therapy is an effective form of palliative treatment for bone metastases.

There are more than 25 randomized controlled trials demonstrating that SFRT provides the same amount of pain control as multiple-fraction radiation therapy (MFRT); however, there is low use internationally of SFRT for bone metastases.

“Use of Single- versus Multiple-Fraction Palliative Radiation Therapy for Bone Metastases: Population-Based Analysis of 16,898 Courses in a Canadian Province,” is one of the largest, current studies on the use of SFRT. The study was designed to determine the use of SFRT in British Columbia, a publicly funded health care system where there is no financial incentive for extended fractionation and all radiation therapy is provided by the BC Cancer Agency with no direct cost to patients.

Patients who received palliative radiation therapy for bone metastases, regardless of the primary cancer site at diagnosis, from 2007 to 2011 were identified using the BC Cancer Agency’s Cancer Agency Information System (CAIS). During the study period, 8,601 patients received 16,898 courses of radiation therapy.

Patients who received re-irradiation for bone metastases were included, and patients who received more than one course of radiation therapy were considered independently for each course (patients could be counted more than once). Radiation therapy fractionation was divided into two categories: SFRT or MFRT. The most common primary disease site was breast (23.4 percent), and the most frequently treated bony metastatic site was the spine (42.2 percent).

SFRT was used to treat bone metastases in 49.2 percent (7,097) of the radiation therapy courses. SFRT was most commonly used to treat bone metastases that originated from hematological (56.6 percent) and prostate (56.1 percent) cancers; the most common bony metastatic sites treated with SFRT were the ribs (83 percent) and extremity (66.4 percent).

There was a significant variation in the use of SFRT by each of the five cancer centers operated by the BC Cancer Agency during the time of the study, with a range of 25.5 percent to 73.4 percent (p<.001). The study found that the overall utilization rate of SFRT in British Columbia is 49.2 percent, a rate consistent with other Canadian and European data that shows SFRT use ranges from 32 percent to 64 percent. SFRT use is much higher, however, than in the United States, where SFRT use ranges from only 3 percent to 13 percent.

“Previous research has shown that single-fraction radiation therapy is equally as effective as longer multiple-fraction courses. Single-fraction radiation therapy offers greater convenience for patients, is associated with fewer side effects and incurs a lower cost. Even a modest change in the frequency of single-fraction radiation therapy use, in Canada and America, could lead to meaningful cost-savings, improved patient convenience and reduced patient side effects, thereby increasing patients’ quality of life,” said Robert A. Olson, MD, MSc, lead author of the study, and the research and clinical trials lead and a radiation oncologist at the BC Cancer Agency Centre for the North. “As a result of discussing our study outcomes among radiation oncologists in British Columbia, we have already seen an increase in the use of single-fraction radiation therapy for bone metastases. We are hopeful that these results will motivate practice change worldwide.”

For a copy of the study manuscript, contact ASTRO’s Press Office. Learn more about the Red Journal.