Perspective from Tracy Balboni, MD, MPH
September 17, 2014
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Single-fraction radiation effective for bone metastases

Perspective from Tracy Balboni, MD, MPH
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Patients with bone metastases who underwent single-fraction palliative radiation therapy reported similar improvements in pain, function and distress as those who underwent multiple-fraction radiation therapy, according to study results presented at the ASTRO Annual Meeting.

The population-based findings support results of prior randomized controlled trials and confirm that single-fraction radiotherapy should be standard for this patient population, researchers wrote.

Robert A. Olson, MD, MSc

Robert A. Olson

“Why is this important? Obviously, it’s costly,” Robert A. Olson, MD, MSc, the research and clinical trials lead and a radiation oncologist at BC Cancer Agency Centre for the North, said during a press conference. “We estimated that if the United States was to uptake use of single-fraction radiation, the cost savings could approach half a billion dollars annually. It’s also more convenient for patients … and there are more acute side effects from the higher dose of the multiple-fraction course.”

Prior research demonstrated single-fraction radiation therapy is equally effective as multiple-fraction radiation therapy for patients with painful bone metastases. However, there is considerable variability in the use of the single-fraction course.

Remuneration could be driving some of the usage of multiple-fraction radiation therapy, which typically consists of five fractions in Canada and Europe and often exceeds 10 courses in the United States. Another potential factor is that most studies of single-fraction radiation therapy have been limited to well-controlled clinical trials, and many physicians may be nervous about extrapolating the data.

In the current study, Olson and colleagues assessed patient-reported outcomes after single-fraction or multiple-fraction radiation therapy for bone metastases in hopes of determining whether single-fraction radiation therapy is equally effective as a multiple-fraction regimen in the clinical practice setting.

The analysis included 284 patients. About two-thirds had uncomplicated bone metastases. Mean age at diagnosis was 64 years and 50% were men. The most common primary tumor sites were genitourinary (29%), lung (24%) and breast (20%). The most common site treated was the spine (47%).

The treating oncologist had the discretion to choose the radiation regimen; 59% of patients in the cohort received single-fraction radiation therapy, and 41% received multiple-fraction radiation therapy.

Investigators at six centers recorded patient-reported outcomes prior to radiotherapy, as well as 3 weeks after. Outcomes were standardized to a 5-point scale, allowing comparisons between treatment groups.

Olson and colleagues reported no significant differences in changes in mean improvement in patient-reported scores for pain (1.29 vs. 1.17; P=.24), function (0.8 vs. 0.95; P=.17) or degree of symptom distress (1.26 vs. 1.26; P=.98) between patients who received single-fraction radiation vs. multiple-fraction radiation.

The percentage of patients who demonstrated a partial pain response (73% vs. 73%; P=0.93) and a complete pain response (19% vs. 22%; P=.31) were similar between the single-fraction and multiple-fraction groups. The percentages of patients who reported at least 1-point improvements in pain (68.2% vs. 7%; P=.78), distress (78.5% vs. 80.7%; P=.74) and function (73.2% vs. 66.7%; P=.41) also were similar between patients assigned single-fraction and multiple-fraction radiation therapy.

After researchers controlled for sex, site of delivery, age of diagnosis and disease site, they observed no significant difference in the probability for improvement in at least one category between the single-fraction and multiple-fraction groups (OR=1.43; 95% CI, 0.76-2.68).

When researchers evaluated results based on the nature of patients’ metastases, they determined single-fraction and multiple-fraction regimens were comparable among patients with uncomplicated bone metastases, as well as those with complicated metastases.

“This prospective study supports trial evidence that single-fraction radiotherapy is as effective as multiple-fraction radiotherapy in the clinical practice setting — or as some people would term it, the ‘real-world’ setting — not just in a selected group of patients in clinical trials,” Olson said.

For more information:

Conway J. Abstract #172. Presented at: ASTRO Annual Meeting; Sept. 14-17, 2014; San Francisco. 

Disclosure: The researchers report no relevant financial disclosures.