Post-operative re-irradiation with hyperthermia in locoregional breast cancer recurrence: Temperature matters

Akke Bakker*, C. Paola Tello Valverde, Geertjan van Tienhoven, M. Willemijn Kolff, H. Petra Kok, Ben J. Slotman, Inge R. H. M. Konings, Arlene L. Oei, Hester S. A. Oldenburg, Emiel J. T. Rutgers, Coen R. N. Rasch, H. J. G. Desirée van den Bongard, Hans Crezee

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Purpose: To investigate the impact of hyperthermia thermal dose (TD) on locoregional control (LRC), overall survival (OS) and toxicity in locoregional recurrent breast cancer patients treated with postoperative re-irradiation and hyperthermia. Methods: In this retrospective study, 112 women with resected locoregional recurrent breast cancer treated in 2010–2017 with postoperative re-irradiation 8frx4Gy (n = 34) or 23frx2Gy (n = 78), combined with 4–5 weekly hyperthermia sessions guided by invasive thermometry, were subdivided into ‘low’ (n = 56) and ‘high’ TD (n = 56) groups by the best session with highest median cumulative equivalent minutes at 43 °C (Best CEM43T50) < 7.2 min and ≥7.2 min, respectively. Actuarial LRC, OS and late toxicity incidence were analyzed. Backward multivariable Cox regression and inverse probability weighting (IPW) analysis were performed. Results: TD subgroups showed no significant differences in patient/treatment characteristics. Median follow-up was 43 months (range 1–107 months). High vs. low TD was associated with LRC (p = 0.0013), but not with OS (p = 0.29) or late toxicity (p = 0.58). Three-year LRC was 74.0% vs. 92.3% in the low and high TD group, respectively (p = 0.008). After three years, 25.0% and 0.9% of the patients had late toxicity grade 3 and 4, respectively. Multivariable analysis showed that distant metastasis (HR 17.6; 95%CI 5.2–60.2), lymph node involvement (HR 2.9; 95%CI 1.2–7.2), recurrence site (chest wall vs. breast; HR 4.6; 95%CI 1.8–11.6) and TD (low vs. high; HR 4.1; 95%CI 1.4–11.5) were associated with LRC. TD was associated with LRC in IPW analysis (p = 0.0018). Conclusions: High thermal dose (best CEM43T50 ≥ 7.2 min) was associated with significantly higher LRC for patients with locoregional recurrent breast cancer treated with postoperative re-irradiation and hyperthermia, without augmenting toxicity.

Original languageEnglish
Pages (from-to)149-157
Number of pages9
JournalRadiotherapy and Oncology
Publication statusPublished - 1 Feb 2022

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