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Review Article

Temperature and thermal dose during radiotherapy and hyperthermia for recurrent breast cancer are related to clinical outcome and thermal toxicity: a systematic review

, , , ORCID Icon, &
Pages 1023-1038 | Received 29 Jul 2019, Accepted 30 Aug 2019, Published online: 17 Oct 2019
 

Abstract

Objective: Hyperthermia therapy (HT), heating tumors to 40–45 °C, is a known radiotherapy (RT) and chemotherapy sensitizer. The additional benefit of HT to RT for recurrent breast cancer has been proven in multiple randomized trials. However, published outcome after RT + HT varies widely. We performed a systematic review to investigate whether there is a relationship between achieved HT dose and clinical outcome and thermal toxicity for patients with recurrent breast cancer treated with RT + HT.

Method: Four databases, EMBASE, PubMed, Cochrane library and clinicaltrials.gov, were searched with the terms breast, radiotherapy, hyperthermia therapy and their synonyms. Final search was performed on 3 April 2019. Twenty-two articles were included in the systematic review, reporting on 2330 patients with breast cancer treated with RT + HT.

Results: Thirty-two HT parameters were tested for a relationship with clinical outcome. In studies reporting a relationship, the relationship was significant for complete response in 10/15 studies, in 10/13 studies for duration of local control, in 2/2 studies for overall survival and in 7/11 studies for thermal toxicity. Patients who received high thermal dose had on average 34% (range 27%–53%) more complete responses than patients who received low thermal dose. Patients who achieved higher HT parameters had increased odds/probability on improved clinical outcome and on thermal toxicity.

Conclusion: Temperature and thermal dose during HT had significant influence on complete response, duration of local control, overall survival and thermal toxicity of patients with recurrent breast cancer treated with RT + HT. Higher temperature and thermal dose improved outcome, while higher maximum temperature increased incidence of thermal toxicity.

Acknowledgments

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Disclosure statement

The authors report no conflict of interest.