INTRODUCTION/BACKGROUND: Men with highest GS ≥ 7 and a differing, lower GS core (ComboGS) have decreased PC-specific mortality (PCSM) risk after RT or RT and androgen deprivation therapy (ADT).
Whether the greatest percentage of involved core length (GPC) modulates this risk is unknown.
PATIENTS AND METHODS: Men with GS ≥ 7 PC (n = 333) consecutively treated between December 1989 and July 2000 using RT (n = 268; 80%) or RT and 6 months of ADT (n = 65; 20%) comprised the study cohort. The GPC was calculated using biopsy core and tumor lengths. We used competing risks regression to assess whether increasing GPC was associated with increased PCSM risk in men with or without ComboGS adjusting for risk group, age, and treatment.
RESULTS: After a median follow-up of 5.36 years (interquartile range, 3.22-7.61 years), 92 (28%) men died, 28 (30%) of PC. Increasing GPC was significantly associated with increased risk of PCSM (adjusted hazard ratio, 1.02; 95% confidence interval, 1.01-1.03; P = .005). Men with GPC ≥ 50% versus < 50% had significantly greater PCSM estimates when ComboGS was present (P < .001) versus absent (P = .55). Of the 127 men with ComboGS and GPC < 50%, 83% were treated with RT alone and 2 PC deaths were observed; neither in men with GS 7 and favorable intermediate-risk PC.
CONCLUSION: Men treated with RT for ComboGS, GPC < 50%, GS 7, and favorable intermediate-risk PC have a very low risk of early PCSM. The RTOG 0815 trial will establish whether ADT is necessary to optimize curability in these men.
Written by:
Cheney MD, Chen MH, Zhang D, Phillips JG, Loffredo MJ, D'Amico AV. Are you the author?
Harvard Radiation Oncology Program, Boston, MA; Department of Statistics, University of Connecticut, Storrs, CT; Department of Radiation Oncology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Boston, MA.
Reference: Clin Genitourin Cancer. 2014 Feb 4. pii: S1558-7673(14)00014-7.
doi: 0.1016/j.clgc.2014.01.006
PubMed Abstract
PMID: 24594503
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