The American Society for Radiation Oncology (ASTRO) Clinical Affairs and Quality Committee has developed an evidence-based guideline, published Jan. 28 in the International Journal of Radiation Oncology*Biology*Physics, with the goal of standardizing the optimal use of radiation therapy in treating bone metastases. The guideline authors concluded that radiotherapy is a successful and time efficient method by which to palliate pain and/or prevent the morbidity of bone metastases.

Bone metastases are caused when a malignant tumor spreads to the bone. They can lead to debilitating effects including pain, fractures and paralysis due to spinal cord compression. The care of these patients requires collaboration between several types of cancer treatment specialists.

External beam radiation therapy (EBRT) provides successful pain relief in 50 to 80 percent of patients with little risk of side effects. However, the widespread variation in practice patterns between radiation oncologists presented an opportunity to standardize care through the construction of a formal treatment guideline, noted ASTRO.

The guideline's lead author Stephen T. Lutz, MD, a radiation oncologist at Blanchard Valley Regional Cancer Center in Findlay, Ohio, said, "Radiation therapy is commonly used to treat bone metastases and has been proven very effective, but with the variety of radiation therapies available and range of successful fractionation schedules, it's important to provide physicians with this guideline to assure they are using the most appropriate methods in treating patients."

Some of the committee's findings include:

• EBRT continues to be the mainstay for treating bone metastases.
• Both single doses and longer courses of radiation have shown similar pain relief outcomes, and each has advantages. A single course has proven more convenient for patients and caregivers, while longer courses have a lower incidence of repeat treatment to the same site.
• Repeat irradiation with EBRT might be feasible in some circumstances, though the details of its effectiveness and safety are still to be determined.
• Bisphosphonates do not eliminate the need for EBRT for painful metastases, and they act effectively when combined with EBRT.
• Stereotactic body radiation therapy can be considered for patients with a newly discovered or recurrent tumor in the spinal column or paraspinal areas; however, it is suggested that stereotactic treatment be reserved for patients who meet specific criteria, who are treated at centers with sufficient training and experience, and who are part of a therapeutic trial.
• Radionuclides are most appropriate for patients who have several sites of painful osteoblastic metastases (like those that are commonly associated with prostate cancer) that cannot be conveniently or safely treated with EBRT.
• Surgical decompression and stabilization plus postoperative radiation therapy should be considered for some patients with single-level spinal cord compression or spinal instability.