Updated Clinical Guideline of Palliative Radiation Therapy for Painful Bone Metastases

Analysis confirms the safety and efficacy of palliative radiation therapy for painful bone metastases.

The American Society for Radiation Oncology (ASTRO) recently released updated evidence-based guidelines underscoring the safety and efficacy of palliative radiation therapy (RT) for the treatment of painful bone metastases.

As cancer metastasizes, it can spread to the skeletal system and cause bone metastases. The primary goal of these malignancies is to relieve some of the symptoms, such as spinal cord compression and pain, and to suppress local disease. RT is a viable option to relieve symptoms associated with bone metastases.

The updated guidelines maintain the 4 prior dosing schedule recommendations for external RT to treat previously unirradiated tumors: single 8 Gray (Gy) fraction of RT; 20 Gy administered in 5 fractions; 24 Gy in 6 fractions; or 30 Gy in 10 fractions. Evidence shows that patients experience similar pain relief and toxicity rates among each of the fractionation options.

Clinical trials have cited higher retreatment rates for patients who received single-fraction RT; however, the task force said that the convenient nature of this option may make it an optimal choice for patients with limited life expectancy.

Recent data from a clinical trial published in JAMA Oncology recommend that a single 8-Gy RT dose for bone metastases should be offered to all patients, including those with poor survival.

Similarly, an increased adoption of the single-fraction approach may reduce disparities between the number of patients who benefit from the therapy and the markedly small number who actually receive the treatment.

Surveys of palliative care professionals indicate that a vast majority of respondents consider RT to be an important component of hospice care, but do not actually refer many of their patients for the therapy. In a study, 88% of hospice professionals said the painful bone metastases merited a palliative RT referral, but only 3% of hospice patients nationwide actually received the treatment. The study cited length of treatment, transportation, and cost as key reasons for underutilization of the therapy.

“Decades of research and many clinical trials have established that the radiation therapy provides safe, effective, and quick pain relief for patients suffering from bone metastases,” said Stephen Lutz, MD, FASTRO, radiation oncologist and chair of the task force that developed the updated guideline. “Moreover, this relief can be achieved in as little as a single fraction, which alleviates the additional burdens of time, travel, and cost for the patient.”

The task force also addressed retreatment of bone metastases, recommending that reirradiation be considered if patients experience recurrent or persistent pain for more than a month following external-beam radiation therapy (EBRT) to treat spine lesions or peripheral bone metastasis. Studies examining reirradiation have shown moderate efficacy.

The role of advanced RT techniques, such as stereotactic body radiation therapy (SBRT), in primary and retreatment of painful bone metastases was also considered in the guideline. SBRT delivers a highly targeted, escalated dose of radiation to the tumor, while reducing the amount of damage to surrounding tissue. Although emerging evidence suggests the potential of SBRT to treat spinal metastases, research is limited compared with EBRT.

The guidelines recommend that the use of advanced RT techniques for primary treatment or retreatment of spinal lesions should only be considered in clinical trials or registry settings. Furthermore, it recommends that physicians consult the current ASTRO white paper on SBRT to aid in treatment decisions.

The guideline was published in Practical Radiation Oncology, and was based on a systematic literature review of studies published from December 2009 through January 2015. In total, 414 abstracts were obtained from PubMed, with 56 articles meeting the studies’ inclusion criteria that were abstracted into evidence tables and evaluated by an expert panel of 8 radiation oncologists and experts in metastatic disease.