George A Plataniotis1, Roger G Dale. 1. Department of Oncology, Aberdeen Royal Infirmary, Aberdeen, United Kingdom. george.plataniotis@nhs.net
Abstract
PURPOSE: To find a biologically effective dose (BED) response for adjuvant breast radiotherapy (RT) for initial-stage breast cancer. METHODS AND MATERIALS: Results of randomized trials of RT vs. non-RT were reviewed and the tumor control probability (TCP) after RT was calculated for each of them. Using the linear-quadratic formula and Poisson statistics of cell-kill, the average initial number of clonogens per tumor before RT and the average tumor cell radiosensitivity (alpha-value) were calculated. An alpha/beta ratio of 4 Gy was assumed for these calculations. RESULTS: A linear regression equation linking BED to TCP was derived: -ln[-ln(TCP)] = -ln(No) + alpha(*) BED = -4.08 + 0.07 (*) BED, suggesting a rather low radiosensitivity of breast cancer cells (alpha = 0.07 Gy(-1)), which probably reflects population heterogeneity. From the linear relationship a sigmoid BED-response curve was constructed. CONCLUSION: For BED values higher than about 90 Gy(4) the radiation-induced TCP is essentially maximizing at 90-100%. The relationship presented here could be an approximate guide in the design and reporting of clinical trials of adjuvant breast RT.
PURPOSE: To find a biologically effective dose (BED) response for adjuvant breast radiotherapy (RT) for initial-stage breast cancer. METHODS AND MATERIALS: Results of randomized trials of RT vs. non-RT were reviewed and the tumor control probability (TCP) after RT was calculated for each of them. Using the linear-quadratic formula and Poisson statistics of cell-kill, the average initial number of clonogens per tumor before RT and the average tumor cell radiosensitivity (alpha-value) were calculated. An alpha/beta ratio of 4 Gy was assumed for these calculations. RESULTS: A linear regression equation linking BED to TCP was derived: -ln[-ln(TCP)] = -ln(No) + alpha(*) BED = -4.08 + 0.07 (*) BED, suggesting a rather low radiosensitivity of breast cancer cells (alpha = 0.07 Gy(-1)), which probably reflects population heterogeneity. From the linear relationship a sigmoid BED-response curve was constructed. CONCLUSION: For BED values higher than about 90 Gy(4) the radiation-induced TCP is essentially maximizing at 90-100%. The relationship presented here could be an approximate guide in the design and reporting of clinical trials of adjuvant breast RT.
Authors: Randall J Kimple; Nancy Klauber-DeMore; Cherie M Kuzmiak; Dag Pavic; Jun Lian; Chad A Livasy; WingKeung M Chiu; Dominic T Moore; Carolyn I Sartor; David W Ollila Journal: Ann Surg Oncol Date: 2011-04 Impact factor: 5.344
Authors: Grazia Lazzari; Angela Terlizzi; Giuseppina Della Vittoria Scarpati; Francesco Perri; Vincenzo De Chiara; Barbara Turi; Giovanni Silvano Journal: Onco Targets Ther Date: 2017-03-24 Impact factor: 4.147