Niloy R Datta1, Stephan Bodis2. 1. Centre for Radiation Oncology KSA-KSB, Kantonsspital Aarau, Switzerland. Electronic address: niloyranjan.datta@ksa.ch. 2. Centre for Radiation Oncology KSA-KSB, Kantonsspital Aarau, Switzerland; Department of Radiation Oncology, University Hospital Zurich, Switzerland.
Abstract
PURPOSE: Hyperthermia inhibits the repair of irradiation-induced DNA damage and thereby could alter the α/β values of tumours. This study estimates the clinical α/βHTRT values from clinical trials of thermoradiotherapy (HTRT) vs radiotherapy (RT) in recurrent breast (RcBC), head and neck (III/IV) (LAHNC) and cervix cancers (IIB-IVA) (LACC). METHODS: Three recently published meta-analyses for HTRT vs RT in RcBC, LAHNC and LACC were evaluated for complete response (CR). Studies with specified RT dose (D), dose/fraction (d) and corresponding CRs were selected. Tumour biological effective dose (BED) for each study with RT (BEDRT) was computed assuming an α/βRT of 10 Gy. As outcomes were favourable with HTRT, thermoradiobiological BED (BEDHTRT) was calculated as a product of BEDRT and %CRHTRT/%CRRT. The α/βHTRT was estimated as Dd/(BEDHTRT - D). RESULTS: 12 trials with 864 patients were shortlisted - RcBC (3 studies, n = 259), LAHNC (5 studies, n = 338) and LACC (4 studies, n = 267). Overall risk difference of 0.28 favoured HTRT (p < 0.001). Mean BEDRT and BEDHTRT were 64.7 Gy (SD: ±15.5) and 109.5 Gy (SD: ±32.1) respectively and global α/βHTRT was 2.25 Gy (SD: ±0.79). Mean α/βHTRT for RcBC, LAHNC and LACC were 2.05 Gy, 1.74 Gy and 3.03 Gy respectively. On meta-regression, α/βHTRT was the sole predictor for the corresponding risk differences of the studies (coefficient = -0.096; p = 0.03). CONCLUSION: Thermoradiobiological effects on the repair of RT induced DNA damage results in reduction in α/β values of tumours. This should be considered to effectively optimize HTRT dose-fractionation schedules in the clinic.
PURPOSE:Hyperthermia inhibits the repair of irradiation-induced DNA damage and thereby could alter the α/β values of tumours. This study estimates the clinical α/βHTRT values from clinical trials of thermoradiotherapy (HTRT) vs radiotherapy (RT) in recurrent breast (RcBC), head and neck (III/IV) (LAHNC) and cervix cancers (IIB-IVA) (LACC). METHODS: Three recently published meta-analyses for HTRT vs RT in RcBC, LAHNC and LACC were evaluated for complete response (CR). Studies with specified RT dose (D), dose/fraction (d) and corresponding CRs were selected. Tumour biological effective dose (BED) for each study with RT (BEDRT) was computed assuming an α/βRT of 10 Gy. As outcomes were favourable with HTRT, thermoradiobiological BED (BEDHTRT) was calculated as a product of BEDRT and %CRHTRT/%CRRT. The α/βHTRT was estimated as Dd/(BEDHTRT - D). RESULTS: 12 trials with 864 patients were shortlisted - RcBC (3 studies, n = 259), LAHNC (5 studies, n = 338) and LACC (4 studies, n = 267). Overall risk difference of 0.28 favoured HTRT (p < 0.001). Mean BEDRT and BEDHTRT were 64.7 Gy (SD: ±15.5) and 109.5 Gy (SD: ±32.1) respectively and global α/βHTRT was 2.25 Gy (SD: ±0.79). Mean α/βHTRT for RcBC, LAHNC and LACC were 2.05 Gy, 1.74 Gy and 3.03 Gy respectively. On meta-regression, α/βHTRT was the sole predictor for the corresponding risk differences of the studies (coefficient = -0.096; p = 0.03). CONCLUSION: Thermoradiobiological effects on the repair of RT induced DNA damage results in reduction in α/β values of tumours. This should be considered to effectively optimize HTRT dose-fractionation schedules in the clinic.
Authors: Adriana M De Mendoza; Soňa Michlíková; Johann Berger; Jens Karschau; Leoni A Kunz-Schughart; Damian D McLeod Journal: Sci Rep Date: 2021-03-09 Impact factor: 4.379
Authors: Ioannis Androulakis; Rob M C Mestrom; Miranda E M C Christianen; Inger-Karine K Kolkman-Deurloo; Gerard C van Rhoon Journal: Cancers (Basel) Date: 2022-03-10 Impact factor: 6.639