Giulia Marvaso1, Delia Ciardo2, Sara Gandini3, Giulia Riva4, Emanuele Frigo5, Stefania Volpe4, Cristiana Fodor2, Dario Zerini2, Damaris Patricia Rojas2, Stefania Comi6, Raffaella Cambria6, Federica Cattani6, Gennaro Musi7, Ottavio De Cobelli8, Roberto Orecchia9, Barbara A Jereczek-Fossa4. 1. Department of Radiation Oncology, European Institute of Oncology, IRCCS, Milan, Italy. Electronic address: giulia.marvaso@ieo.it. 2. Department of Radiation Oncology, European Institute of Oncology, IRCCS, Milan, Italy. 3. Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy. 4. Department of Radiation Oncology, European Institute of Oncology, IRCCS, Milan, Italy; Division of Epidemiology and Biostatistics, IEO, European Institute of Oncology IRCCS, Milan, Italy; Department of Oncology and Hematoncology, University of Milan, Milan, Italy. 5. Department of Oncology and Hematoncology, University of Milan, Milan, Italy. 6. Unit of Medical Physics, IEO, European Institute of Oncology, IRCCS, Milan, Italy. 7. Department of Urology, IEO, European Institute of Oncology, IRCCS, Milan, Italy. 8. Department of Oncology and Hematoncology, University of Milan, Milan, Italy; Unit of Medical Physics, IEO, European Institute of Oncology, IRCCS, Milan, Italy; Department of Urology, IEO, European Institute of Oncology, IRCCS, Milan, Italy. 9. Scientific Directorate, European Institute of Oncology IRCCS, Milan, Italy.
Abstract
PURPOSE: To compare clinical outcomes and toxicities of 2 radiation therapy (RT) schemes for localized prostate cancer (PCa): extreme hypofractionation (EH; fractions of 6.5-7 Gy to a total dose of 32.5-35 Gy) and the moderate hypofractionation (MH; 26 fractions of 2.7 Gy to a total dose of 70.2 Gy). A propensity score method was used to compare the EH-RT and MH-RT groups. METHODS AND MATERIALS: Our analysis included a total of 421 patients divided in 2 groups: 227 treated with MH-RT and 194 treated with EH-RT (43 and 30 months median follow-up, respectively). Propensity matching created comparable cohorts. Statistical evaluations were performed on the whole cohort, stratifying the analyses by risk strata factors identified with the propensity scores, and on a subgroup of patients matched by propensity score. Multivariate proportional hazard Cox models were used to compare the 2 groups, mainly for gastrointestinal and genitourinary toxicity and secondarily for clinical progression-free survival, biochemical progression-free survival, and overall survival. RESULTS: Considering the whole population, acute genitourinary and gastrointestinal greater than grade 1 was significantly more frequent in the whole MH-RT group (P < .001 and P < .002, respectively). A borderline significantly greater late genitourinary was confirmed with the multivariate analysis (P = .07). Concerning tumor outcome, no statistically significant differences were observed. After propensity score matching, 226 patients were included in the analysis. The 2 obtained propensity score matched groups did not differ for any of the clinical and pathologic variables considered for the analysis, resulting in well-balanced cohorts. The results obtained on the whole population were confirmed in the matched groups. CONCLUSIONS: EH-RT yields a decreased risk of acute or late toxicities compared with MH-RT, and oncologic outcomes were comparable. Our data indicate that EH-RT might be considered as a treatment modality of choice for select patients with PCa.
PURPOSE: To compare clinical outcomes and toxicities of 2 radiation therapy (RT) schemes for localized prostate cancer (PCa): extreme hypofractionation (EH; fractions of 6.5-7 Gy to a total dose of 32.5-35 Gy) and the moderate hypofractionation (MH; 26 fractions of 2.7 Gy to a total dose of 70.2 Gy). A propensity score method was used to compare the EH-RT and MH-RT groups. METHODS AND MATERIALS: Our analysis included a total of 421 patients divided in 2 groups: 227 treated with MH-RT and 194 treated with EH-RT (43 and 30 months median follow-up, respectively). Propensity matching created comparable cohorts. Statistical evaluations were performed on the whole cohort, stratifying the analyses by risk strata factors identified with the propensity scores, and on a subgroup of patients matched by propensity score. Multivariate proportional hazard Cox models were used to compare the 2 groups, mainly for gastrointestinal and genitourinary toxicity and secondarily for clinical progression-free survival, biochemical progression-free survival, and overall survival. RESULTS: Considering the whole population, acute genitourinary and gastrointestinal greater than grade 1 was significantly more frequent in the whole MH-RT group (P < .001 and P < .002, respectively). A borderline significantly greater late genitourinary was confirmed with the multivariate analysis (P = .07). Concerning tumor outcome, no statistically significant differences were observed. After propensity score matching, 226 patients were included in the analysis. The 2 obtained propensity score matched groups did not differ for any of the clinical and pathologic variables considered for the analysis, resulting in well-balanced cohorts. The results obtained on the whole population were confirmed in the matched groups. CONCLUSIONS:EH-RT yields a decreased risk of acute or late toxicities compared with MH-RT, and oncologic outcomes were comparable. Our data indicate that EH-RT might be considered as a treatment modality of choice for select patients with PCa.