Effect of Radiotherapy on Painful Bone Metastases: A Secondary Analysis of the NCIC Clinical Trials Group Symptom Control Trial SC.23

Abstract

Importance: Many studies that found improved quality of life (QOL) after radiotherapy of bone metastases have small sample sizes and do not use specific questionnaires. How soon after radiotherapy one can expect an improvement in QOL is unknown.

Objective: To investigate QOL at days 10 and 42 after radiotherapy with a bone metastases-specific QOL tool.

Design, setting, and participants: In this secondary analysis of the NCIC Clinical Trials Group Symptom Control Trial SC.23, a double-blind randomized clinical trial that investigated dexamethasone for the prophylaxis of pain flare after radiotherapy, patients were accrued from 23 Canadian centers from May 30, 2011, to December 11, 2014, and were followed up for 42 days after treatment. Participants referred for radiotherapy for bone metastases were required to have a pain score at the site(s) of treatment of at least 2 (range, 0-10).

Interventions: Patients were treated with a single 8-Gy radiotherapy dose for 1 or 2 bone metastases.

Main outcomes and measures: Patients reported their worst pain score and analgesic intake at baseline and days 10 and 42 after treatment. Pain response was assessed with International Bone Metastases Consensus Endpoint Definitions. Self-reported QOL was completed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Bone Metastases Module (QLQ-BM22) and the European Organisation for Research and Treatment of Cancer Quality of Life Core 15 Palliative (QLQ-C15-PAL) at the same time points.

Results: A total of 298 patients were accrued (median age, 68.8 [range, 32-94] years at day 10 and 68.0 [range, 34-90] years at day 42). A total of 122 patients (40.9%) responded to radiotherapy at day 10 and 116 patients (38.9%) at day 42. At day 10, compared with nonresponders, patients with a pain response had a greater reduction in pain (mean reduction, 17.0 vs 1.8; P = .002) and pain characteristics (mean reduction, 12.8 vs 1.1; P = .002), as well as greater improvements in functional interference (mean increase, 11.6 vs 3.6; P = .01) and psychosocial aspects (mean increase, 1.2 points in responders vs mean decrease of 2.2 points in nonresponders, P = .04). Comparing changes in QOL from baseline to day 42, responders had significantly greater improvements in the physical (mean increase, 6.2 vs -9.0; P < .001), emotional (mean increase, 12.3 vs -5.5; P < .001), and global domains (mean increase, 10.3 vs -4.5; P < .001) of the QLQ-C15-PAL compared with nonresponders.

Conclusions and relevance: Forty percent of patients experienced pain reduction and better QOL at day 10 after radiotherapy with further improvements in QOL at day 42 in responders. A single 8-Gy radiotherapy dose for bone metastases should be offered to all patients, even those with poor survival.

Trial registration: clinicaltrials.gov Identifier: NCT01248585.