Local control of bone metastases treated with external beam radiotherapy in recent years: a multicenter retrospective study

Kenji Makita,Yasushi Hamamoto,Kotaro Uwatsu,Shintaro Tsuruoka,Teruhito Kido,Hiromitsu Kanzaki,Hirofumi Ishikawa,Kei Nagasaki,Shuhei Yamamoto,Noriko Takata,Masaaki Kataoka

doi:10.1186/s13014-021-01940-0

Kenji Makita, Yasushi Hamamoto + Show 9 more

Open Access

https://doi.org/10.1186/s13014-021-01940-0

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Abstract

BackgroundOver the past decades, remarkable advancements in systemic drug therapy have improved the prognosis of patients with bone metastases. Individualization is required in external beam radiotherapy (EBRT) for bone metastases according to the patient’s prognosis. To establish individualized EBRT for bone metastases, we investigated factors that affect the local control (LC) of bone metastases.MethodsBetween January 2010 and December 2019, 536 patients received EBRT for 751 predominantly osteolytic bone metastases. LC at EBRT sites was evaluated with a follow-up computed tomography. The median EBRT dose was biologically effective dose (BED10) (39.0) (range of BED10: 14.4–71.7 Gy).ResultsThe median follow-up time and median time of computed tomography follow-up were 11 (range 1–123) months and 6 (range 1–119) months, respectively. The 0.5- and 1-year overall survival rates were 73% and 54%, respectively. The 0.5- and 1-year LC rates were 83% and 79%, respectively. In multivariate analysis, higher age (≥ 70 years), non-vertebral bone metastases, unfavorable primary tumor sites (esophageal cancer, colorectal cancer, hepatobiliary/pancreatic cancer, renal/ureter cancer, sarcoma, melanoma, and mesothelioma), lower EBRT dose (BED10 < 39.0 Gy), and non-administration of bone-modifying agents (BMAs)/antineoplastic agents after EBRT were significantly unfavorable factors for LC of bone metastases. There was no statistically significant difference in the LC between BED10 = 39.0 and BED10 > 39.0 Gy.ConclusionsRegarding tumor-related factors, primary tumor sites and the sites of bone metastases were significant for the LC. As for treatment-related factors, lower EBRT doses (BED10 < 39.0 Gy) and non-administration of BMAs/antineoplastic agents after EBRT were associated with poor LC. Dose escalation from BED10 = 39.0 Gy did not necessarily improve LC.

Highlights

Over the past decades, remarkable advancements in systemic drug therapy have improved the prognosis of patients with bone metastases
For the moderately unfavorable group of primary tumor sites, the 1-year local control (LC) rates of Biologically effective dose (BED10) = 39.0 and BED10 > 39.0 Gy were 78% and 86%, respectively (HR 1.75, 95% confidence intervals (CIs) 0.70–4.36, p = 0.232)
For the favorable group of primary tumor sites, the 1-year LC rates of B ED10 = 39.0 and BED10 > 39.0 Gy were 90% and 94%, respectively (HR 1.16, 95% CI 0.63–2.13, p = 0.631)

Summary

Introduction

Remarkable advancements in systemic drug therapy have improved the prognosis of patients with bone metastases. Individualization is required in external beam radiotherapy (EBRT) for bone metastases according to the patient’s prognosis. Various tumors frequently result in bone metastases, which are found in 70–85% of advanced cancers diagnosed at the time of death [1]. The incidence rate of bone metastases depends on the primary tumor site and is comparatively higher in breast, prostate, or lung cancers. Radiotherapy is useful for pain relief of bone metastases. In terms of pain relief and adverse events, singlefraction external beam radiotherapy (EBRT) of 8 Gy is comparable with 30 Gy in 10 fractions or 20 Gy in five fractions [3]. Many guidelines for managing of bone metastases recommend single-fraction EBRT of 8 Gy for pain relief of uncomplicated bone metastases. The incidence rate of retreatment was lower in fractionated EBRT than in single-fraction EBRT [5]

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