By: Colby Strong
Concurrent chemoradiotherapy is tolerable and reduces pain better than radiotherapy alone for patients with breast cancer and painful bone metastases, according to research published in the Journal of Bone Oncology.
The randomized, phase 2 study included 84 patients with breast cancer and painful bone metastases. The patients were randomly assigned to radiotherapy only (42 patients) or radiotherapy with concurrent capecitabine (42 patients).
In both groups, radiotherapy was given at 30 Gy in 10 fractions, 5 days a week. Capecitabine was given at 825 mg/m2 every 12 hours, 5 days a week, concurrently with radiotherapy.
At baseline, the radiotherapy-alone group had a mean age of 47.29 years, 76.2% were hormone receptor positive, and 66.7% were HER2 negative. The capecitabine group had a mean age of 47.71 years, 71.4% were hormone receptor positive, and 57.1% were HER2 negative.
There was no significant difference in toxicity between the 2 groups, and all side effects were grade 1 or 2 in nature.
The incidence of grade 1 diarrhea was 9.5% in the radiotherapy-alone group and 14.3% in the capecitabine group. Grade 2 diarrhea was only seen in the capecitabine group (4.8%).
There were similar rates of grade 1 nausea (14.3% in the radiotherapy-alone group and 23.8% in the capecitabine group), grade 1 weakness (14.3% and 19.0%, respectively), and grade 1 radiation dermatitis (9.5% and 19.0%, respectively).
Grade 1 hand and foot syndrome and grade 1 mucositis were each seen in 4.8% of patients in the capecitabine arm but none of the patients in the radiotherapy-alone arm.
Response was based on pain and analgesic scores. Complete response (CR) was defined as a pain score of 0 at the treated site, with no increase in analgesic intake. Partial response (PR) was defined as a reduction in pain score by 2 or more at the treated site, without an increase in analgesic intake. The overall response rate (ORR) includes patients with a CR or PR.
The ORR increased over time and stabilized at weeks 8 and 12. The ORR at week 1 was 28.6% in the radiotherapy-alone group and 57.1% in the capecitabine group. At week 4, the ORR was 47.6% and 81%, respectively. The difference in response between the groups was significant from week 1 (P =.018) through week 12 (P =.004).
At week 12, the CR rate was 19.0% in the radiotherapy-alone group and 42.9% in the capecitabine group. The PR rate was 23.8% and 38.1%, respectively.
The researchers acknowledged that this study was limited by the small number of patients and short follow-up, which prevented evaluation of pain recurrence and long-term toxicities.
Ahmed S, Kamal SM, Salah T, Fawzy Sedik M, Youssief AA. Concurrent capecitabine with external beam radiotherapy versus radiotherapy alone in painful bone metastasis of breast cancer origin. J Bone Oncol. Published online October 16, 2021. https://doi.org/10.1016/j.jbo.2021.100395
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