Main Session
Sep
29
PQA 06 - Genitourinary Cancer, Gynecological Cancer, and Health Care Access and Engagement
Presenter(s)
Katherine Amarell, MD, BS - Cleveland Clinic Foundation, Cleveland, OH
K. Amarell1, C. A. Reddy2, J. P. Ciezki3, M. A. Weller4, I. Abu-Gheida5, K. L. Stephans6, R. D. Tendulkar3, and S. Moningi7; 1Cleveland Clinic Foundation, Cleveland, OH, 2Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic Foundation, Cleveland, OH, 3Department of Radiation Oncology, Cleveland Clinic Foundation, Cleveland, OH, 4Department of Radiation Oncology, Cleveland Clinic, Cleveland, OH, 5The University of Texas MD Anderson Cancer Center, Houston, TX, 6Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, 7Cleveland Clinic, Cleveland, OH
Purpose/Objective(s):
Moderate hypofractionation has become a standard treatment approach for localized prostate cancer, supported by randomized trials demonstrating noninferior oncologic outcomes compared with conventional fractionation. However, long-term data beyond 10 years remain limited, particularly for dose-escalated regimens. We report our institution’s 15-year outcomes of 70 Gy in 28 fractions, evaluating long-term disease control and treatment-related toxicity.Materials/Methods:
An IRB-approved database was queried for patients with localized prostate cancer treated with moderately hypofractionated intensity modulated radiation therapy (IMRT) with daily image guidance between 1998 and 2012. Intermediate-risk disease was stratified as favorable (one intermediate-risk factor) or unfavorable (=2 intermediate-risk factors). Biochemical relapse-free survival (bRFS), clinical relapse-free survival (cRFS), and overall survival (OS) were estimated using the Kaplan–Meier method. Prostate cancer–specific mortality (PCSM) and treatment-related toxicity, graded per CTCAE, were analyzed using cumulative incidence analysis. Cox regression analysis identified factors associated with biochemical failure (bF), clinical failure (cF), and OS, and competing risk regression analysis was used for PCSM.Results:
A total of 854 patients were included with a median follow-up of 14.1 years (maximum 27.4 years). Median age was 68 years (range 40–87) and median initial PSA was 8.6 ng/mL (range 0.37–250). Risk distribution was 31.1% low risk (LR), 27.9% favorable intermediate risk (FIR), 12.4% unfavorable intermediate risk (UIR), and 28.6% high risk (HR). Androgen deprivation therapy was not used in 39.1% of patients, administered for 1–6 months in 49.8%, and for >6 months in 11.1%. The 15-year bRFS by risk group was 77.4% for LR, 71.9% for FIR, 61.5% for UIR, and 36.5% for HR. The 15-year cRFS by risk group was 87.7% for LR, 86.6% for FIR, 82.4% for UIR, and 51.8% for HR. The 15 and 20-year actuarial OS for the entire cohort was 49.5% (95% CI 46-52.9) and 29.5% (26.3–32.7), respectively, and 15-year OS by risk group was 36.0% for LR, 32.4% for FIR, 23.2% for UIR, and 21.3% for HR. The 15-year PCSM was 4.7% for LR, 5.6% for FIR, 5.9% for UIR, and 19.3% for HR, with an overall 15 and 20-year PCSM of 9.1% (95% CI 7.3-11.2) and 9.9% (8.0–12.1), respectively. On multivariable analysis, initial PSA and Gleason score were associated with bF, while age and Gleason score were associated with cF, OS, and PCSM. Late toxicity remained low with a 15-year cumulative incidence of grade =3 genitourinary toxicity of 3.3% and grade =3 gastrointestinal toxicity of 1.8%.Conclusion:
Moderately hypofractionated IG-IMRT with 70 Gy in 28 fractions for localized prostate cancer continues to show robust 15-year clinical outcomes with a low incidence of high-grade toxicity. This fractionation scheme remains an appropriate option for all risk groups.