Radiotherapy concurrent versus sequential with endocrine therapy in breast cancer: A meta-analysis

• Eleven eligible studies were retrieved to process a meta-analysis.
• Different treatment timing didn't affect radiation-induced toxicity and survival.
• Tamoxifen and AI didn't influence outcomes.

IntroductionThis study compared treatment outcomes of radiotherapy concurrent with endocrine therapy and radiotherapy sequential with endocrine therapy in breast cancer.Materials and methodsEligible studies of radiotherapy concurrent and sequential with endocrine therapy in breast cancer were retrieved through extensive searches of the PubMed, Medline, Embase, Cochrane library, FEBM, FMJS, Web of science, Wiley, CBM, CNKI, Wang fang, Cqvip databases from 2000 to 2014. Original English and Chinese publications of radiotherapy concurrent and sequential with endocrine therapy in breast cancer were included. The primary endpoint was radiation-induced toxicity including upper than grade 2 skin related toxicity, radiation pneumonia and pulmonary fibrosis; the second endpoint was survival date, including local recurrence, distant metastasis, 5-year OS, 10-year OS.ResultsEleven eligible trials were identified, six in English and five in Chinese. Totally, there were 1291 women in concurrent groups, and 1179 in sequential groups. Statistical analysis showed that there was no statistical difference between concurrent and sequential groups in skin related toxicity (RR 1.20, 95% CI 0.92–1.56, P = 0.17), radiation pneumonia (RR 1.11, 95% CI 0.46–2.70, P = 0.81) and pulmonary fibrosis (RR 1.35, 95% CI 0.75–2.41, P = 0.32). Meanwhile, no statistical difference was found in survival data, (RR 0.97, 95% CI 0.79–1.28, P = 0.26), (RR 0.86, 95% CI 0.66–1.12, P = 0.27) in local recurrence and distant metastasis respectively, (RR 1.01, 95% CI 0.96–1.06, P = 0.65), (RR 0.98, 95% CI 0.93–1.02, P = 0.32) in 5-year and 10-year overall survival respectively. Stratification analysis was proceeded, grouped by tamoxifen and AI in different treatment timing, however, no statistical difference was found in radiation-induced toxicity and survival outcomes.ConclusionRadiotherapy concurrent with endocrine therapy didn't increase or decrease neither the incidence of radiation-induced toxicity nor the survival rate compared with that of sequential group; Endocrine therapy drugs didn't influence outcomes in different treatment timing.