Background: stereotac c body radiotherapy (SBRT) has emerged as an effec ve treatment for localized prostate cancer. However, prostate-specific an gen (PSA) kine cs a'er SBRT has not been well characterized. The objec ve of the current study is to analyze the rate of PSA decline and PSA nadir following hypofractonated SBRT in localized prostate cancer. Materials and Methods: From 2008 to 2014, thirty-nine pa ents newly diagnosed, localized prostate (25.6% low risk, 66.7% intermediate risk and 7.7% high risk) cancer were treated with SBRT using Cyberknife. Total dose of 36.25 Gy in 5 frac ons of 7.25 Gy were administered. No one received androgen depriva on therapy (ADT). PSA nadir and rate of change in PSA (slope) were calculated and compared. Results: With a median follow-up of 52 months (range, 13-71), the median rates of decline of PSA were -0.372, -0.211 and -0.128 ng/mL/month, respec vely, for dura ons of 1, 2 and 3 years a'er radiotherapy, respec vely. The decline of PSA was maximal in the first year and con nuously decreased for dura ons of 2 and 3 year. The median PSA nadir was 0.28 ng/mL a'er a median 33 months. There was one biochemical failure, occurring in a high risk pa ent. 5-year actuarial biochemical failure (BCF) free survival was 94.2%. Conclusion: In this report of localized prostate cancer, con nuous decrease of PSA level for dura on 1, 2 and 3 year following SBRT using Cyberknife resulted in lower PSA nadir. Also, SBRT leaded to long-term favorable BCF-free survival.

This study aims to quantitatively evaluate the light and radiation fields of a linear accelerator by developing an optical sensor quality assurance (QA) system using a cadmium sulfide (CdS) photodetector cell and a hardware base frame manufactured in-house. The CdS photodetector cell used as the optical sensor has a size of 3.4 × 4.1 mm2, can measure up to 100 lux of light, and has a response time of approximately 20 to 30 ms. To check the alignment of the light field, it was manufactured with a CdS cell optical fiber holder, and the microcontroller board and control module were configured to scan the light field profile. Additionally, for accurate operation of the sensor, it was programmed using the integrated development environment (IDE) sketch. The alignment check of the radiation field was analyzed using the image data measured with electronic portal imaging device (EPID) using the manufactured hardware base frame. An analysis program written in MATLAB was used to evaluate the alignment of the radiation field. For symmetric fields measured using the optical sensor QA system, the full width at half maximum (FWHM) values of crossline (X) and inline (Y) profiles were 100.391 mm and 98.725 mm, respectively, for a field size of 100 × 100 mm2, and 199.093 mm and 198.886 mm, respectively, for a field size of 200 × 200 mm2. The X and Y FWHM values measured by the sensor system for the light fields were within 1 mm of the field size of the visual inspection. In addition, the FWHM value of the asymmetric radiation field measured using the fabricated frame and EPID was measured from the center bearing ball of the field to the bearing ball in each field of the four directions in the EPID image, and when the X1, X2, Y1, and Y2 jaws were opened by 50 mm, FWHM values were 50.120 mm, 50.240 mm, 48.860 mm, and 49.870 mm, respectively. The corresponding values were 99.520 mm, 99.570 mm, 99.010 mm, and 99.880 mm when the jaw fields were opened by 100 mm. The optical sensor system and hardware base frame developed in this study demonstrated the ability to evaluate both light and radiation fields more simply and quantitatively when compared to the conventional QA process. This QA system will provide medical physicists with more reliable QA results than the conventional QA method that uses graph paper and film.

Measures, RAND, and American College of Surgeons Commission on Cancer-endorsed quality-of-care measures. Results: We found excellent compliance with metrics focusing on the accuracy and completeness of staging and management documentation. Completeness of TNM staging, biopsy and surgical pathology reporting, and assessment of baseline urologic and sexual function was 100%. This was also true for discussion of active surveillance management in appropriate cases. Assessment and documentation of post-treatment quality-oflife outcomes increased for surgical and radiation therapy management outcomes. Specific effort was made on the PQRS clinical care objective for adjuvant hormonal therapy for high-risk prostate cancers. For unfavorable intermediate-risk cases, 55% of patients were advised on combined therapy, with only 22% receiving concurrent therapies. For high-risk prostate cancers, 100% of patients were advised on receiving hormonal therapy, with 76% ultimately receiving combined hormone ablation and radiation therapy. For high-risk patients, an increase in completing comprehensive evaluations with medical and radiation oncology consultations in addition to surgical consultation was achieved: Before implementing the high-risk management guidelines, 60% of patients completed medical and/or radiation oncology consultations. With best practice guidelines, 87% of patients completed comprehensive multidisciplinary consultations before initiation of definitive treatment, resulting in a significant reduction in the number of high-risk patients managed surgically. Conclusion: Implementation of an institutional provider-directed initiative based on established metrics achieved improvements in appropriate and effective clinical care based on established quality metrics. Continued improvements can be realized in the multidisciplinary management of advanced and high-risk prostate cancers.

Cox regression analysis. PSA doubling time and nadir before increase were prognostically significant in case of PSA recurrence (10-year overall survival of 71% vs. 41% with PSA doubling time >6 months vs. <6 months; P Z 0.01; 63% vs. 46% with a nadir <1ng/mL vs. >1ng/mL; P Z 0.02). Conclusion: Rising PSA levels particularly in the second year following RT after reaching a nadir <1ng/mL indicates a prognostically favorable PSA bounce. A short PSA doubling time and a higher nadir are associated with an adverse prognosis in case of a PSA recurrence.