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Pahlajani N , Ruth KJ , Buyyounouski MK , Chen DY , Horwitz EM , Hanks GE , Price RA , Pollack A
Radiotherapy doses of 80 Gy and higher are associated with lower mortality in men with Gleason score 8 to 10 prostate cancer
Int J Radiat Oncol Biol Phys. 2012 Apr 1;82(5) :1949-56
PMID: 21763081    PMCID: PMC3827957    URL: https://www.ncbi.nlm.nih.gov/pubmed/21763081
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Abstract
PURPOSE: Men with Gleason score (GS) 8-10 prostate cancer (PCa) are assumed to have a high risk of micrometastatic disease at presentation. However, local failure is also a major problem. We sought to establish the importance of more aggressive local radiotherapy (RT) to >/=80 Gy. METHODS AND MATERIALS: There were 226 men treated consecutively with RT +/- ADT from 1988 to 2002 for GS 8-10 PCa. Conventional, three-dimensional conformal or intensity-modulated (IM) RT was used. Radiation dose was divided into three groups: (1) <75 Gy (n = 50); (2) 75-79.9 Gy (n = 60); or (3) >/=80 Gy (n = 116). The endpoints examined included biochemical failure (BF; nadir + 2 definition), distant metastasis (DM), cause-specific mortality, and overall mortality (OM). RESULTS: Median follow-up was 66, 71, and 58 months for Groups 1, 2, and 3. On Fine and Gray's competing risk regression analysis, significant predictors of reduced BF were RT dose >/=80 Gy (p = 0.011) and androgen deprivation therapy duration >/=24 months (p = 0.033). In a similar model of DM, only RT dose >/=80 Gy was significant (p = 0.007). On Cox regression analysis, significant predictors of reduced OM were RT dose >/=80 Gy (p = 0.035) and T category (T3/4 vs. T1, p = 0.041). Dose was not a significant determinant of cause-specific mortality. Results for RT dose were similar in a model with RT dose and ADT duration as continuous variables. CONCLUSION: The results indicate that RT dose escalation to >/=80 Gy is associated with lower risks of BF, DM, and OM in men with GS 8-10 PCa, independently of androgen deprivation therapy.
Notes
Pahlajani, Niraj Ruth, Karen J Buyyounouski, Mark K Chen, David Y T Horwitz, Eric M Hanks, Gerald E Price, Robert A Pollack, Alan eng P30 CA006927/CA/NCI NIH HHS/ R01 CA101984/CA/NCI NIH HHS/ CA-006927/CA/NCI NIH HHS/ CA101984-01/CA/NCI NIH HHS/ Research Support, N.I.H., Extramural Research Support, Non-U.S. Gov't Int J Radiat Oncol Biol Phys. 2012 Apr 1;82(5):1949-56. doi: 10.1016/j.ijrobp.2011.04.005. Epub 2011 Jul 15.