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

Bakker, A.; Valverde, C.P.T.; Tienhoven, G. van; Kolff, M.W.; Kok, H.P.; Slotman, B.J.; ... ; Crezee, H. (2022)

Article / Letter to editor

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 degrees 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. (C) 2021 The Authors. Published by Elsevier B.V.

• Locoregional recurrent breast cancer
• Re-irradiation
• Hyperthermia
• Dose-effect relationship
• Thermal dose
• Locoregional control
• Toxicity
• Propensity score
• Inverse probability weighting

• All authors: Bakker, A.; Valverde, C.P.T.; Tienhoven, G. van; Kolff, M.W.; Kok, H.P.; Slotman, B.J.; Konings, I.R.H.M.; Oei, A.L.; Oldenburg, H.S.A.; Rutgers, E.J.T.; Rasch, C.R.N.; Bongard, H.J.G.D. van den; Crezee, H.
• Date: 2022-02-01
• Journal: Radiotherapy & Oncology
• Volume: 167
• Pages: 149 - 157
• DOI: doi:10.1016/j.radonc.2021.12.036
• Link: https://www.sciencedirect.com/science/article/pii/S0167814021090848?via%...