Yasir Alayed1, Andrew Loblaw2, Merrylee McGuffin3, Hans T Chung2, Chia-Lin Tseng2, Laura D'Alimonte3, Patrick Cheung2, Stanley Liu2, William Chu2, Ewa Szumacher2, Joelle Helou4, Ananth Ravi2, Masoom Haider5, Alexandre Mamedov3, Liying Zhang3, Gerard Morton6. 1. Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada; Radiation Oncology, College of Medicine, King Saud University, Riyadh, Saudi Arabia. 2. Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada. 3. Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada. 4. Department of Radiation Oncology, University of Toronto, Princess Margaret Cancer Centre, Canada. 5. Mount Sinai Hospital, Toronto, Canada. 6. Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Canada; Department of Radiation Oncology, University of Toronto, Canada. Electronic address: gerard.morton@sunnybrook.ca.
Abstract
PURPOSE: Single-fraction HDR monotherapy for the treatment of localized prostate cancer is appealing, but published outcomes are discouraging. An approach to improve local control is MRI-guided focal dose-escalation to the dominant intraprostatic lesion (DIL). Here we report a comparison of outcomes from two phase II clinical trials with and without a focal boost. METHODS: Patients had low or intermediate-risk disease. Patients in Trial1 received a single 19 Gy HDR implant to the whole prostate. Trial2 incorporated an additional MRI-guided focal DIL boost to at least 23 Gy. ADT was not allowed. Toxicities (CTCAEv4.0) and quality of life (EPIC) were collected. Biochemical failure (BF) was defined as nadir +2. Univariate and multivariate logistic regression analysis was conducted to search for predictors of BF. RESULTS: Trial1 had 87 patients with a median follow-up of 62 months, while Trial2 had 60 patients with a median follow-up of 50 months. The five-year cumulative BF rate was 32.6% and 31.3%, respectively (p = 0.9). 77.5% of failures were biopsy-confirmed local failures, all of which underwent local salvage therapy. The addition of a DIL boost was not associated with worse toxicity or QOL. Baseline PSA and Gleason score correlated with BF, but none of the dosimetric parameters was a significant predictor of BF. CONCLUSIONS: MRI-guided focal boost was safe and well tolerated, but did not improve local control after 19 Gy single-fraction HDR monotherapy, and the control rates were unacceptable. Single-fraction HDR monotherapy for prostate cancer should not be offered outside of clinical trials.
PURPOSE: Single-fraction HDR monotherapy for the treatment of localized prostate cancer is appealing, but published outcomes are discouraging. An approach to improve local control is MRI-guided focal dose-escalation to the dominant intraprostatic lesion (DIL). Here we report a comparison of outcomes from two phase II clinical trials with and without a focal boost. METHODS: Patients had low or intermediate-risk disease. Patients in Trial1 received a single 19 Gy HDR implant to the whole prostate. Trial2 incorporated an additional MRI-guided focal DIL boost to at least 23 Gy. ADT was not allowed. Toxicities (CTCAEv4.0) and quality of life (EPIC) were collected. Biochemical failure (BF) was defined as nadir +2. Univariate and multivariate logistic regression analysis was conducted to search for predictors of BF. RESULTS: Trial1 had 87 patients with a median follow-up of 62 months, while Trial2 had 60 patients with a median follow-up of 50 months. The five-year cumulative BF rate was 32.6% and 31.3%, respectively (p = 0.9). 77.5% of failures were biopsy-confirmed local failures, all of which underwent local salvage therapy. The addition of a DIL boost was not associated with worse toxicity or QOL. Baseline PSA and Gleason score correlated with BF, but none of the dosimetric parameters was a significant predictor of BF. CONCLUSIONS: MRI-guided focal boost was safe and well tolerated, but did not improve local control after 19 Gy single-fraction HDR monotherapy, and the control rates were unacceptable. Single-fraction HDR monotherapy for prostate cancer should not be offered outside of clinical trials.
Authors: Joel Poder; Dylan Koprivec; Yashiv Dookie; Andrew Howie; Dean Cutajar; Antonio L Damato; Nicolas Côté; Marco Petasecca; Joseph Bucci; Anatoly Rosenfeld Journal: Med Phys Date: 2022-04-19 Impact factor: 4.506