PURPOSE - We sought to analyze whether outcomes of biochemical relapse-free survival (bRFS), late genitourinary (GU), and late gastrointestinal toxicity are different for prostate cancer patients with small (≤60 cc) vs.
large (>60 cc) prostates following low dose-rate brachytherapy.
MATERIALS AND METHODS - The bRFS outcomes for 2076 low- or intermediate-risk prostate cancer patients from 1996 to 2012 were determined from a review of a prospectively maintained database. All patients were treated with (125)I monotherapy without androgen deprivation therapy. Biochemical failure was defined per the Phoenix definition. Patient-related factors and dosimetric values were examined in Cox regression analyses for bRFS and late toxicity. Late toxicity was scored according to a modified Common Terminology Criteria for Adverse Events version 4. 0 scale.
RESULTS - The median followup for all patients was 55 months. The 5-year bRFS rates for all patients, prostates >60 cc, and prostates ≤60 cc were 93. 4% (95% confidence interval [CI]: 92. 1%, 94. 7%), 96. 7% (95% CI: 94. 4%, 98. 9%), and 92. 9% (95% CI: 91. 4%, 94. 3%), respectively. On multivariable analysis, prostate size >60 cc was significantly associated with improved bRFS (p = 0. 01), as were initial prostate-specific antigen and biopsy Gleason score (p < 0. 0001 and p = 0. 0002, respectively). Patients with prostates >60 cc had significantly higher rates of Grade 3-4 late GU toxicity at 5 years than patients with smaller prostates; 7. 2% (95% CI: 4. 0%, 10. 4%) and 3. 2% (95% CI: 2. 3%, 4. 1%), respectively (p = 0. 0007). The overall late gastrointestinal toxicity rate for all patients was 0. 7% at 5 years with no significant difference between the two groups.
CONCLUSIONS - Implantation of large prostates >60 cc results in favorable bRFS outcomes and is associated with increased but acceptable rates of Grade 3 and higher late GU toxicities.
Brachytherapy. 2016 Jan 18 [Epub ahead of print]
Yvonne D Pham, Jeffrey A Kittel, Chandana A Reddy, Jay P Ciezki, Eric A Klein, Kevin L Stephans, Rahul D Tendulkar
Department of Radiation Oncology, Cleveland Clinic Taussig Cancer Institute, Cleveland, OH. , Department of Radiation Oncology, Cleveland Clinic Taussig Cancer Institute, Cleveland, OH. , Department of Radiation Oncology, Cleveland Clinic Taussig Cancer Institute, Cleveland, OH. , Department of Radiation Oncology, Cleveland Clinic Taussig Cancer Institute, Cleveland, OH. , Department of Urology, Cleveland Clinic Glickman Urological and Kidney Institute, Cleveland, OH. , Department of Radiation Oncology, Cleveland Clinic Taussig Cancer Institute, Cleveland, OH. , Department of Radiation Oncology, Cleveland Clinic Taussig Cancer Institute, Cleveland, OH.
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