W James Morris1, Ingrid Spadinger2, Mira Keyes3, Jeremy Hamm4, Michael McKenzie3, Tom Pickles3. 1. Department of Radiation Oncology, Vancouver Cancer Centre, Vancouver, British Columbia, Canada; Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address: jmorris@bccancer.bc.ca. 2. Department of Medical Physics, Vancouver Cancer Centre, Vancouver, British Columbia, Canada. 3. Department of Radiation Oncology, Vancouver Cancer Centre, Vancouver, British Columbia, Canada; Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada. 4. Department of Cancer Surveillance and Outcomes, British Columbia Cancer Agency, Vancouver, British Columbia, Canada.
Abstract
PURPOSE: To examine the relationship between whole prostate dose metrics and disease-free survival (DFS) after (125)I low-dose-rate prostate brachytherapy (LDR-PB). METHODS AND MATERIALS: Data for the first 2000 LDR-PB monotherapy implants were extracted from a database containing patient, tumor, dosimetric, and outcomes information. By National Comprehensive Cancer Network criteria, half (n = 1006) had low-risk disease and half (n = 990) had intermediate-risk disease (four had high-risk disease). Most patients (58.4%) and 75.3% of intermediate-risk patients received 3 months neoadjuvant and 3 months concomitant androgen deprivation therapy (ADT). Univariate and multivariate analyses were conducted using recognized prognostic factors and the whole prostate dose metrics D90 (the minimum dose received by 90% of the postimplant CT-based prostate volume) and V100 (the percent of the postimplant CT-based prostate volume that received at least 100% of the prescription dose). RESULTS: The median followup is 5 years (maximum, 12.5 years); the 5-, 7-, and 10-year actuarial DFS estimates are 96.0%, 94.4%, and 93.0%, respectively. Of the recognized prognostic factors, only pretreatment prostate-specific antigen (p = 0.012) and Gleason sum (p = 0.010) were predictive of DFS. When analyzed as continuous variables, dose metrics were not predictive of DFS. However, most nonsignificant trends favored higher doses, and D90 values <130 Gy were predictive of an increased risk of recurrence in the non-ADT subset (N = 833; log rank, p = 0.018). CONCLUSIONS: Although D90 values of <130 Gy were predictive of an increased risk of recurrence in the non-ADT subset, neither D90 nor V100, when used as continuous variables, was predictive of DFS when applied to the entire cohort or in the subset analysis. This observation informs us that dose metrics are not equivalent to oncologic end points and must be calibrated against DFS for each physician and each institution offering LDR-PB.
PURPOSE: To examine the relationship between whole prostate dose metrics and disease-free survival (DFS) after (125)I low-dose-rate prostate brachytherapy (LDR-PB). METHODS AND MATERIALS: Data for the first 2000 LDR-PB monotherapy implants were extracted from a database containing patient, tumor, dosimetric, and outcomes information. By National Comprehensive Cancer Network criteria, half (n = 1006) had low-risk disease and half (n = 990) had intermediate-risk disease (four had high-risk disease). Most patients (58.4%) and 75.3% of intermediate-risk patients received 3 months neoadjuvant and 3 months concomitant androgen deprivation therapy (ADT). Univariate and multivariate analyses were conducted using recognized prognostic factors and the whole prostate dose metrics D90 (the minimum dose received by 90% of the postimplant CT-based prostate volume) and V100 (the percent of the postimplant CT-based prostate volume that received at least 100% of the prescription dose). RESULTS: The median followup is 5 years (maximum, 12.5 years); the 5-, 7-, and 10-year actuarial DFS estimates are 96.0%, 94.4%, and 93.0%, respectively. Of the recognized prognostic factors, only pretreatment prostate-specific antigen (p = 0.012) and Gleason sum (p = 0.010) were predictive of DFS. When analyzed as continuous variables, dose metrics were not predictive of DFS. However, most nonsignificant trends favored higher doses, and D90 values <130 Gy were predictive of an increased risk of recurrence in the non-ADT subset (N = 833; log rank, p = 0.018). CONCLUSIONS: Although D90 values of <130 Gy were predictive of an increased risk of recurrence in the non-ADT subset, neither D90 nor V100, when used as continuous variables, was predictive of DFS when applied to the entire cohort or in the subset analysis. This observation informs us that dose metrics are not equivalent to oncologic end points and must be calibrated against DFS for each physician and each institution offering LDR-PB.
Authors: T Shaikh; N G Zaorsky; K Ruth; D Y Chen; R E Greenberg; J Li; K Crawford; E M Horwitz Journal: Brachytherapy Date: 2014-11-07 Impact factor: 2.362
Authors: Giovanni Fellin; Maria A Mirri; Luigi Santoro; Barbara A Jereczek-Fossa; Claudio Divan; Salvatore Mussari; Francesco Ziglio; Beniamino La Face; Fernando Barbera; Michela Buglione; Laura Bandera; Barbara Ghedi; Nadia G Di Muzio; Andrea Losa; Paola Mangili; Luciano Nava; Renato Chiarlone; Nunzia Ciscognetti; Emilio Gastaldi; Federica Cattani; Ruggero Spoto; Andrea Vavassori; Francesca R Giglioli; Alessia Guarneri; Valentina Cerboneschi; Marcello Mignogna; Mauro Paoluzzi; Valentina Ravaglia; Costanza Chiumento; Stefania Clemente; Vincenzo Fusco; Roberto Santini; Marco Stefanacci; Francesco P Mangiacotti; Marco Martini; Tiziana Palloni; Giuseppe Schinaia; Grazia Lazzari; Giovanni Silvano; Stefano Magrini; Umberto Ricardi; Riccardo Santoni; Roberto Orecchia Journal: Br J Radiol Date: 2016-07-07 Impact factor: 3.039