Response and Quality of Life (QoL) Outcomes in a Randomized Trial of Single versus Multiple Fractions for Re-Irradiation of Painful Bone Metastases: NCIC CTG SC.20
The following reports were chosen because of their relevance to patients during and after cancer treatment. These presentations were made at the 55th annual meeting of the American Society for Radiation Oncology (ASTRO) in Atlanta Georgia.
Presenter Name: Edward Chow
Presenter Affiliation: Sunnybrook Health Sciences Centre, Odette Cancer Centre, Toronto, ON, Canada.
Bone metastases are a common occurrence in patients with cancer, most commonly seen in breast, prostate and lung cancer. Unfortunately, bone metastases tend to cause discomfort and are the most common cause of intractable pain among cancer patients. Radiation is an effective treatment in the management of bone metastases, with the goals of care to relieve pain and prevent fracture.
Due to advances in supportive care and systemic agents, patients with metastatic disease to bone are now living longer. As such, some patients with painful bone metastases who underwent radiation therapy for treatment are now living long enough to have return or worsening of pain, requiring repeat treatment. Some previous research has shown radiation to be effective in the repeat treatment of painful bone metastases, however there has been no evaluation of the optimal dose in this setting.
The current study was a world wide, multi-center randomized control trial looking to determine the optimal repeat radiation dose and number of treatments (fractions) for painful bone metastases.
850 patients with painful bone metastases that had been previously treated with radiation were randomly assigned to receive either a single fraction (total dose = 8 Gy) or multiple fractions (total dose = 20 Gy). In the group that received multiple fractions, either 5 or 8 fractions were used depending on location of bone metastases and the number of previous fractions of radiation used.
The primary focus of the study was the response rate (defined by patient’s reported pain and pain medication use), 2 months after radiation started. A patient was classified as responding to treatment if any of the following were true:
- Patients had no pain with stable or decreased pain medication use
- Patients had an improvement in pain without an increase in pain medication
- Patients had a decrease in pain medication without an increase in pain.
Of the initial 850 patients who were enrolled in the study, 521 were treated per protocol and had data to evaluate. Overall there was no significant difference between the two groups; 119 patients treated with a single fraction had a response versus 136 patients treated with multiple fractions.
Approximately 10% of patients had progression of pain at 6 months, but again there was no difference in this rate between patients treated with one fraction versus multiple fractions. Additionally, there was no difference seen in pathologic fracture rate or spinal cord compression between the two treatment groups.
Patients who were over 60 years of age or who had breast or prostate cancer were more likely to have a response to the repeat treatment at 2 months. They did not find response to previous radiation nor number of fractions used in the prior treatment to be associated with response at 2 months.
There was no difference seen in patient’s quality of life either before or after treatment, regardless of number of fractions. However, patients treated with multiple fractions did report higher rates of side effects at both one week and two weeks after starting treatment. At one week, these included a higher rate of skin reddening (22% v 16%) and nausea (24% v 17%). At two weeks these included skin reddening (22% v 16%), lack of appetite (66% v 56%), vomiting (24% v 13%), and diarrhea (31 v 23%).
In patients with metastatic disease, maintaining quality of life is often the primary goal of treatment. The ability to repeat treatment for painful bone metastases is important in this setting. A question remained as to the best dose and fractionation for repeat treatment. Fewer fractions can translate to fewer trips to the doctor’s office and less cost. As this study showed, a single fraction (total dose = 8 Gy) is not worse than multiple fractions (total dose = 20 Gy); both have a response rate of around 50%. Additionally, multiple fractions did have a higher rate of side effects at both one and two weeks following treatment. Importantly, they also showed that even patients who did not have a response to initial radiation could have a response with a second course of radiation.