Patterns of failure are reported in Table 2. The median follow-up at the time of analysis was 8.3 years (range, 1.2–10.5 years). Two patients (1.2%) with FIR disease received concurrent ADT, with a median length of ADT of 6.5 months. Median times to PSA nadir were 4.5, 3.2, and 4.4 years for the VLR, LR, and FIR groups, respectively. The overall median time to PSA nadir after RT was 3.7 years ( Figure 1B). The PSA nadir by risk group was 0.6, 0.5, and 0.4 ng/mL for the VLR, LR, and FIR groups, respectively. The mean PSA at diagnosis was 5.1 ng/mL ☒.3 ng/mL and the mean PSA nadir after RT was 0.6 ng/mL ☐.5 ng/mL ( Figure 1A). One hundred twenty patients (72%) received double-scattering technique and 46 patients (28%) received non-double scattering technique, as it became available at our institution. Per the institutional review board–approved protocol and typical fractionation that were in effect during that time, all patients were prescribed a treatment dose of 79.2 GyRBE in 44 fractions. The median age at the start of RT was 64 years (range, 42–82 years). Statistical Assessmentīaseline cohort characteristics are described in Table 1. All survival metrics were calculated from start of RT. PC-specific survival (PCSS) and overall survival (OS) were also reported. Regional failure (RF) was used to describe metastasis to pelvic LN, and distant failure (DF) was used to describe all other distant nodal, bony, or solid organ metastases. Local failure (LF) within the prostate or seminal vesicles was described by a recurrence confirmed by either conventional imaging (computed tomography or magnetic resonance imaging) and/or prostatic biopsy procedure. When feasible and if deemed to potentially change clinical management, a prostate biopsy procedure was pursued to confirm recurrence.
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Biochemical failure was followed up with pelvic computed tomography, prostate magnetic resonance imaging, and/or technetium bone scan, guided by clinical evidence and the patient's PSA levels. BF was described according to the Phoenix definition as a rise in prostate-specific antigen (PSA) of 2 ng/mL or greater above the patient's post-RT nadir.
GRAPHPAD PRISM 8 NUMBER AT RISK SERIAL
Serial measurements of PSA were obtained every 3 months for the first 5 years after treatment, then every 6 months thereafter. Patients were retrospectively assessed for baseline characteristics and clinical endpoints by the first author and confirmed by the second and senior authors. The primary outcome measure in this study was biochemical failure–free survival (BFFS) based on initial risk groups in patients undergoing PBT for favorable risk PC.
GRAPHPAD PRISM 8 NUMBER AT RISK PC
Other established treatment options for favorable risk PC include radical prostatectomy (RP) and brachytherapy, but a significant portion of patients are not clinically suitable, or wish to avoid, these invasive procedures. Furthermore, there remains a group of patients who do not elect or are not ideal, reliable candidates for AS. Although still an option for favorable intermediate risk (FIR) patients, AS is not routinely recommended for all patients in this cohort, as it may confer a higher rate of metastatic progression. A growing body of evidence supports active surveillance (AS) as the preferred treatment option for patients with very low-risk (VLR) and low-risk (LR) disease, with the benefit of avoiding treatment-related side effects for PC that is unlikely to progress. A subset of these patients can be further stratified into very-low risk disease, which the National Comprehensive Cancer Network defines as having clinical stage T1c, grade group 1, PSA less than 10 ng/mL, fewer than 3 prostate biopsy fragments/cores positive, less than 50% cancer in each fragment/core, and PSA density less than 0.15 ng/mL/kg. Approximately 40% of newly diagnosed patients present with low-risk disease, which is defined as grade group 1, PSA less than 10 ng/mL, and clinical stage T1c to T2a.
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Despite the controversy and subsequent changes in prostate-specific antigen (PSA) screening recommendations, prostate cancer (PC) remains the most common nonskin cancer diagnosis for males in the United States.