SINGLE FRACTION RT FOR BONE METASTASES

SAN FRANCISCO – The first ever "real world" study of palliative radiotherapy for uncomplicated bone metastases has confirmed that single-fraction radiotherapy (RT) is just as good at relieving pain and maintaining quality of life as multiple fractions.

The single-session approach is thus the preferred option, given its convenience and lesser cost, said study lead author Robert Olson, MD, of the British Columbia (BC) Cancer Agency in Vancouver, Canada.

He spoke at a press conference at the American Society for Radiation Oncology (ASTRO) 56th Annual Meeting, where the new study was presented this week.

Although previous clinical trials have also come to the same conclusion, this is first "real-world study" of single vs multiple palliation approaches, he said. This study involved men and women being seen in actual clinical practice as opposed to clinical trials.

The total evidence has resulted in "multiple guidelines" indicating that single- and multiple-fraction RT are comparable, said Dr. Olson. Also, the 2013 Choosing Wisely campaign from ASTRO recommends that clinicians should not routinely use extended fractionation for palliation of bone metastases.

"One hundred percent of cases should not be palliated with a single fraction, but certainly it should be greater than 50%," Dr. Olson told Medscape Medical News.

In the United States, fewer than 10% of palliative treatments for bone metastases are performed with single-fraction RT, he noted. In Canada and Europe, the rate ranges from 30% to 60%.

The findings from the new study "underscore the safety of the approach," said Tracy Balboni, MD, MPH, of the Dana-Farber/Harvard Cancer Center in Boston, Massachusetts, who moderated the press conference.

"The US needs to adopt evidence-based care for these patients," she added.

The potential impact of modifying palliation of bone mets is tremendous, said Dr. Olson. In the United States, there 250,000 patients with bone metastases for whom palliation with RT is performed each year, he said.

Study Findings

The study reported by Dr. Olson and colleagues was conducted in 648 patients from 6 local BC centers who received radiotherapy either as a single fraction of 8 Gy or as multiple fractions composed of 20 Gy given during a 5-day period.

At the discretion of their physicians, a little more than half of the study participants (56%; 363) received single-fraction palliation, vs fewer than half (44%; 285) who received multiple fractions.

Patients were asked to fill out questionnaires before and after treatment. These self-reported outcomes show similar percentages of partial and complete pain responses from baseline to 4 weeks post treatment with the 2 approaches.

Specifically, partial pain response (an improvement of 1 point on a 5 point scale; P = .93) was identical between the 2 groups (73%).

And complete pain response (a reduction to 0 on a 5-point scale; P = .31) was also comparable between the 2 groups (19% for single and 22% for multiple).

The researchers also performed a multivariate analysis and found, again, that there was no significant difference between the 2 approaches in terms of an odds ratio for complete and partial pain.

The analysis controlled for sex, site of the primary tumor, site of the metastasis, and whether or not the bone met was complicated.

There were also measures of function and symptom distress. And again, the researchers found that there were no significant differences between the 2 approaches.

"Single-fraction radiotherapy should be the standard management policy for uncomplicated bone metastasis," Dr. Olson concluded.

The authors have reported no relevant financial relationships.

American Society for Radiation Oncology (ASTRO) 56th Annual Meeting: Abstract 172. Presented September 16, 2014.