Pain Response Rates After Conventional Radiation Therapy for Bone Metastases in Prospective Nonrandomized Studies: A Systematic Review

Abstract

Purpose: This study aimed to determine the pain response rates after conventional radiation therapy (RT) for painful bone metastases in prospective nonrandomized studies, which better reflect daily practice than randomized controlled trials.

Methods and materials: A literature search was conducted in PubMed and Scopus for articles published between 2002 and 2018. We only included articles in which pain response after RT was assessed using the International Consensus Endpoint initially published in 2002, or the updated version from 2012. In addition, to be included in this review, the study design was required to be prospective or based on prospectively collected data. Our primary outcomes of interest were the overall and complete response rates after conventional RT for bone metastases.

Results: Of the 2863 articles identified in our database search, 12 met the inclusion criteria. Six studies excluded patients with features of complicated bone metastases. Only 2 papers reported exclusion criteria regarding analgesic use. Radiation schedules that were frequently used were 1 × 8 Gy, 5 × 4 Gy, and 10 × 3 Gy. The overall response rate in evaluable patients was 55%, and 754 of the 1379 evaluable patients experienced a complete or partial response. The complete response rate was 15% (196 of 1348 evaluable patients). In the intent-to-treat patient group, the overall response rate was 29% (754 of 2559 enrolled patients), and the complete response rate 8% (196 of 2528 enrolled patients).

Conclusions: We determined the pain response rates after conventional RT for painful bone metastases in prospective nonrandomized studies. The present review may provide benchmarks for future nonrandomized studies that investigate palliative RT for bone metastases.