Randomized trial of short-course versus long-course radiotherapy for palliation of painful vertebral bone metastases: A retrospective analysis of RTOG 97–14

Abstract

9521 Background: RTOG 97–14 [Hartsell et al, breast/prostate cancer patients (pts) with painful bone metastases randomized to 8 Gy/1 fraction or 30 Gy/10 fractions], revealed no difference in pain relief or narcotic use 3 months post randomization. The 8 Gy regimen resulted in fewer acute toxicities, but higher rates of retreatment for recurrent pain. Single 8 Gy fractions for painful vertebral bone mets have not been well accepted, possibly due to provider concerns about efficacy and toxicity. The present study evaluates treatment differences in the subset of pts treated specifically for painful vertebral bone mets (PVBM). Methods: PVBM were treated to the cervical, thoracic, and/or lumbar spine. Chi-square test was used to evaluate population differences between PVBM and non-PVBM. Amongst PVBM, differences in retreatment rates (cumulative incidence method, Gray's test) and in pain relief/BPI worst pain score, narcotic use, and toxicity 3 months post randomization (chi-square test) were evaluated. Results: Of 909 eligible pts, 235 (26%) were PVBM. PVBM and non-PVBM pts differed in % of males [55% vs. 47%,p=0.03] and pts with multiple painful sites [57% vs. 38%,p<0.01]. Amongst PVBM, more 30 Gy pts had multiple sites treated [65% vs. 49%, p=0.02]. T [10% vs. 20%, p=0.01] here was no statistically significant difference (8 vs. 30 Gy) in pain relief [70% vs. 62%, p=0.59] or narcotic use [27% vs. 24%, p=0.76] at 3 months. There were significant differences in acute grade 2–4 toxicityand acute grade 2–4 GI toxicity [6% vs. 14%, p=0.01] at 3 months, lower toxicity seen in 8 Gy. Late toxicity was rare, with 1 grade 3 CNS event (8 Gy) and 1 grade 4 lung event (30 Gy). 8 Gy showed significantly higher 3-year retreatment rates [15% vs. 5%, p=0.01]. Conclusions: Although a clinically different pt population, the results for PVBM are comparable to those of the entire study population. Both 8 Gy/1 fraction and 30 Gy/10 fractions resulted in comparable pain relief and narcotic use at 3 months. Both were well tolerated with few adverse effects. 8 Gy had less acute toxicity, and a higher need for retreatment than 30 Gy. This may have implications for future research comparing single fraction conventional radiation therapy with stereotactic spine radiosurgery. No significant financial relationships to disclose.