Shalini Moningi, MD
MD Anderson Cancer Center
PV QA 1 - Poster Viewing Q&A 1
Purpose/Objective(s): Salvage radiation therapy can provide long-term disease control for men with recurrent disease after prostatectomy but some men fail after treatment. We undertook a prospective study of men receiving intensity-modulated radiation therapy (IMRT) to collect prognostic data and to characterize quality of life after treatment.
Materials/Methods: We enrolled men with at least two consecutive prostate specific antigen (PSA) rises after prostatectomy for node-negative prostate cancer. All men had no evidence of nodal or metastatic disease on pelvic MRI and bone scan. IMRT was delivered to the prostate, seminal vesicle fossa and vesicourethral junction. Androgen deprivation therapy (ADT) was administered if PSA was ≥ 0.5 ng/ml. The 26-item Expanded Prostate Cancer Index Composite (EPIC) measured patient-reported disease-specific function. Higher scores indicate better function. Minimal clinically important difference (MCID) was defined as 6 for urinary incontinence, 5 for urinary irritative/ obstructive, 4 for bowel, and 12 for sexual function. PSA progression was defined as two consecutive PSA rises ≥ 0.1 ng/ml. Descriptive statistics, Cox regression analysis, and Kaplan-Meier survival estimates were performed.
Results: Median age was 58 years, median follow-up 4.7 years and 86% were Caucasian. 63% of men had negative resection margins at prostatectomy. 51% had pT2, 35% had pT3a, and 14% had pT3b disease. 94 men had pre-IMRT PSA <0.5, and 26 had pre-IMRT PSA ≥0.5. All patients received 70Gy. Median Bladder V70 was 15% and Rectal V70 was 12%. EPIC completion at baseline, 6, 12, and 24 months was 100%, 69%, 59%, and 39%. Pretreatment median urinary incontinence, urinary irritative, bowel and sexual function scores were 79, 93, 96, and 31 respectively. 5-year PSA progression free survival (PFS) was 64% for men with PSA < 0.5 ng/ml and 48% for men with PSA ≥0.5. At 5 years, 15% of men with pre-IMRT PSA <0.5 and 50% of men with pre-IMRT PSA ≥ 0.5 had initiated post-IMRT salvage therapy. In multivariate analysis, men with positive margins had better PSA PFS (HR 0.30, p=0.03). 5-year PSA PFS was 86% in men with PSA <0.5 and positive margins. Median function change from baseline at six, 12 and 24 months was 0, -6.3, and -6.3 for incontinence, 0, 0, and -3.6 for urinary irritative, -1.8, -3.6, and 0 for bowel and -2.8, 0, and 1.0 for sexual. The only MCID was urinary incontinence at 12 and 24 months.
Conclusion: Men with positive resection margins at prostatectomy and pre-treatment PSA <0.5 ng/ml have low rates of recurrence after salvage IMRT alone without ADT. Men undergoing salvage radiation have low pretreatment sexual function and do not report clinically significant declines in urinary irritative, bowel or sexual function through 2 years after treatment. Urinary incontinence function 1 and 2 years after treatment was at the threshold of clinically important difference.
MD Anderson Cancer Center
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