Posttreatment Prostate-Specific Antigen 6 Months After Radiation With Androgen Deprivation Therapy Predicts for Distant Metastasis–Free Survival and Prostate Cancer–Specific Mortality

Journal Article · Tue Nov 01 04:00:00 EDT 2016 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2016.07.009· OSTI ID:22645681

Naik, Mihir ^[1]; Reddy, Chandana A.; Stephans, Kevin L.; Ciezki, Jay P. ^[1]; Garcia, Jorge; Grivas, Petros ^[2]; Stephenson, Andrew J.; Klein, Eric A. ^[3]; Tendulkar, Rahul D. ^[1]

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1. Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio (United States)
2. Department of Hematology and Medical Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio (United States)
3. Department of Urology, Glickman Urology and Kidney Institute, Cleveland Clinic, Cleveland, Ohio (United States)

Objectives/Background: To determine whether a 6-month posttreatment prostate-specific antigen (PSA) value in patients with prostate cancer (PCa) treated with concurrent androgen deprivation therapy (ADT) and external beam radiation therapy (EBRT) serves as an early predictor for biochemical relapse free survival (bRFS), distant metastasis–free survival (DMFS), and prostate cancer–specific mortality (PCSM). Methods: A retrospective review of intermediate-risk and high-risk PCa patients treated with EBRT and concurrent ADT at a single institution between 1996 and 2012. All patients received high-dose radiation with either 78 Gy in 39 fractions or 70 Gy in 28 fractions. Kaplan-Meier analysis was used to estimate bRFS and DMFS, and cumulative incidence was used to estimate PCSM. Results: 532 patients were identified. The median follow-up time was 7.5 years (range, 1-16.25 years). The median initial PSA (iPSA) was 13.0 ng/mL (range, 0.37-255 ng/mL), and the median duration of ADT was 6 months (range, 1-78 months). The median PSA 6 months after EBRT was 0.1 ng/mL (range, 0-19 ng/mL), and 310 patients (58.3%) had a 6-month PSA ≤0.1 ng/mL. Multivariable analysis (MVA) demonstrated that a 6-month post-EBRT PSA of >0.1 ng/mL was an independent predictor of worse bRFS (hazard ratio [HR] = 2.518; P<.0001), DMFS (HR=3.743; P<.0001), and PCSM (HR=5.435; P<.0001). On MVA, a Gleason score of 8 to 10 also correlated with worse DMFS and PCSM (P<.05). The duration of ADT (1-6 vs >6 months) was not predictive of any clinical endpoint. Conclusions: A 6-month posttreatment PSA >0.1 ng/mL in intermediate-risk and high-risk PCa patients treated with concurrent high-dose EBRT and ADT is associated with worse bRFS, DMFS, and PCSM. The duration of ADT was not predictive of any clinical endpoint. A 6-month PSA after definitive EBRT and ADT helps identify patients at higher risk of disease progression and may serve as a predictive tool to select patients for early salvage therapy on future clinical trials.

• OSTI ID: 22645681
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 96; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
ANDROGENS
ANTIGENS
CLINICAL TRIALS
EXTERNAL BEAM RADIATION THERAPY
GY RANGE 10-100
MORTALITY
NEOPLASMS
PATIENTS
PROSTATE
RADIATION DOSES