A Novel Perineal Shield for Low-Dose Rate Prostate Brachytherapy

S444

International Journal of Radiation Oncology  Biology  Physics

consisting of LHRH agonist (6 months total) integrated with adriamycin (A) and docetaxel (T). Two dose levels of A and T were incorporated with LHRH agonist therapy, a higher dose (HD) of A (50mg/m2) and T (70mg/m2), and a lower dose (LD) of A (15mg/m2) and T (30mg/m2). HD chemotherapy was given on two separate occasions (3 days post LHRH agonist injection) in an effort to take advantage of the expected testosterone surge that occurs 3-5 days post LHRH agonist treatment, while LD chemotherapy was given at other time points during the six month neoadjuvant period. This was followed by retropubic RP. The median adjuvant RT dose post RP was 70.2 Gy (whole pelvis with 2 cone downs; range: 64.8-70.2) via 3D-CRT. Three patients did not undergo RP after neoadjuvant chemohormone therapy and went on to receive definitve RT (75.6 Gy). The overall survival (OS), disease-free survival (DFS), freedom from PSA failure (bNED, PSA>0.2), and late GI/GU toxicity rates were calculated using the Kaplan-Meier method. Results: Seventy-seven percent of patients received all therapy as planned. Median follow-up for the entire cohort and those alive were 5.9 years (range, 0-10.3) and 6.8 years, respectively. The 7 year OS, DFS and bNED rates were 73%, 45% and 49%, respectively. Six patients (27%) never achieved PSA<0.2. Worst acute grade 3 and 4 toxicity rates were 68% and 32%, respectively. The 7-year actuarial grade 3 or worse late GU toxicity rate was 12.5%. There were no grade 3 or worse late GI toxicities and no grade 5 acute or late toxicity. Conclusions: Our trial demonstrates that this aggressive multimodal approach is feasible and offers encouraging late efficacy and toxicity profile in patients with high-risk prostate cancer. Author Disclosure: Y. Kwok: None. J.W. Snider: None. A. Engelman: None. R.B. Alexander: None. P.P. Amin: None. A. Hussain: None.

symptoms 1 year post radiation follow up are 30.4% and 20.0% for poor bladder fillers and good bladder fillers respectively. Author Disclosure: S. Grimm: None. L. Scharf: None. C. Ma: None. M. Sobczak: None.

2585 Comparison of the IPSS Score Changes 1 Year PosteHigh-Dose Radiation Between Good Bladder Fillers and Poor Bladder Fillers S. Grimm,1 L. Scharf,2 C. Ma,2 and M. Sobczak2; 1Academic Urology of PA, King of Prussia, PA, 2Fox Chase Cancer Center, Philadelphia, PA Purpose/Objective(s): The full bladder instruction is given to all prostate patients at the time of simulation and for daily treatment in our clinic to minimize the radiation to the bladder wall. Yet, it can be a difficult task for some patients to follow the instruction well. This study is to evaluate the late GU toxicities between good bladder fillers and poor bladder fillers. Materials/Methods: Patients receiving high dose radiation for prostate cancer underwent a CBCT once a week. These images were used to compare the CBCT bladder filling during treatment to the planning bladder volume. Staff physicians reviewed these images daily and assigned a grade to the concordance in bladder filling. A sliding scale was used to indicate bladder filling compliance. Using an average of the CBCT scores patients were divided into 3 groups, poor bladder fillers, average fillers, and good to excellent fillers. Using the initial IPSS obtained at consultation we compared this to IPSS at 1 year follow-up to evaluate the differential IPSS. We grouped the differential IPSS into 2 groups, changes of 5 and over 5 from the IPSS baseline. Results: From Jan 2012 to Nov 2012, total of 181 consecutive intact prostate and prostate-bed patients were included in this study. 46 patients were classified as poor bladder fillers and 50 patients fell into the goodexcellent bladder filler group. The percentage of patients experiencing at least 6 point increases in urinary symptoms between poor fillers and goodexcellent fillers were nearly identical at 15.2% vs. 14.0% respectively. We further investigate what is the common feature for those patients with 6 or higher point of IPSS increases. Our study shows that smaller plan CT bladder volume and smaller weekly CBCT bladder demonstrates higher correlation to late GU toxicities. Conclusions: There was no significant increase in urinary symptoms between poor bladder fillers and good-excellent bladder fillers in this study at 1 year post-high dose radiation therapy. A good bladder filler may still experience 6 point increases in IPSS score if their plan CT bladder volume is small. The percentage of patients requiring medication for urinary

2586 A Description of the Failure Patterns of High-Risk Prostate Cancer in the United States: Useful But Incomplete Information From the National Cancer Database Z. Zheng,1 E. Onukwugha,2 C.A. Reddy,3 and J.P. Ciezki3; 1American Cancer Society, Atlanta, GA, 2University of Maryland Baltimore, Baltimore, MD, 3Cleveland Clinic, Cleveland, OH Purpose/Objective(s): Most clinical trials of novel treatments for prostate cancer (CaP) report overall survival or cause-specific survival as their primary endpoint. There is limited evidence about the site-specific treatment failure and persistence of high risk CaP after initial treatment to help guide the direction of future research. The national cancer database (NCDB) provides cancer recurrence information with a recognized rate of missing data. Our objective is to examine the completeness of recurrence information for high risk CaP in the NCDB. Materials/Methods: High risk CaP cases were defined using the following criteria: prostate-specific antigen (PSA) value  20 ng/ml, Gleason Score (GS) 8-10, or clinical stage  T3 (excluding T4). NCDB was used to identify high risk CaP patients aged 18 to 100 years diagnosed between 2004 and 2008 and followed until 2011. Patients were limited to those who underwent radical prostatectomy (RP), external beam radiation (EBRT), or EBRT + hormone therapy (HT) as their first course of treatment. The recurrence of local and distant failure after initial treatment was stratified by the type of treatment received. Results: The study population consisted of 47,717 patients: RP - 16,023; EBRT - 7,978; EBRT + HT - 23,716. The median follow-up is 56.7 months (95% Confidence Interval: 13.9 - 94.6). The overall missing rate for recurrence/persistence is 32%, and varied across treatment groups: RP: 26%; EBRT: 38%; EBRT + HT: 34% (p < .001). Of the remaining patients with complete recurrence information, the prevalence of failure/persistence is 22%, and the treatment specific recurrence/persistence patterns are shown in the Table. Conclusions: Even with a short-term follow-up, 22% of those high-risk patients who had complete recurrence/persistence information are appropriate for local or systemic secondary therapy. Lymph nodes are an uncommon site of persistence/recurrence. Scientific Abstract 2586; Table Treatment Group Recurrence Site Local Lymph Nodes Bone Any Persistence TOTALS

RP N (%) 808 26 71 1153 2058

(6.81) (0.22) (0.59) (9.73) (17.35)

EBRT N (%) 100 (2.02) 8(0.16) 69 (1.39) 1145 (23.15) 1322 (26.73)

EBRT+HT N (%) 377 29 378 2775 3559

(2.41) (0.18) (2.41) (17.73) (22.74)

P-value <.001 <.001 <.001 <.001 <.001

Author Disclosure: Z. Zheng: None. E. Onukwugha: E. Research Grant; Bayer, Amgen. K. Advisory Board; Jansen Analytics, Johnson & Johnson. C.A. Reddy: None. J.P. Ciezki: S. Leadership; Associate Senior Editor of the Red Journal.

2587 A Novel Perineal Shield for Low-Dose Rate Prostate Brachytherapy J.P. Weiner,1,2 D. Schreiber,1,2 A. Polubruv,1 M. Worth,1 T. Telivala,1 J. Safdieh,1,2 and D. Schwartz1,2; 1Veterans Affairs NY Harbor Healthcare System, Brooklyn, NY, 2SUNY Downstate Medical Center, Brooklyn, NY Purpose/Objective(s): To study the impact on radiation exposure to staff through the use of an original perineal shield during low-dose rate prostate brachytherapy.

Volume 90  Number 1S  Supplement 2014 Materials/Methods: We designed a 1-mm thick stainless steel shield with duplicate holes and markings to a standard commercialized prostate brachytherapy grid but with taller and wider dimensions. Two stainless steel latches on the back of the shield allow it to slide over the grid and lock into place. Therefore, when pre-loaded needles are placed into the perineum, they glide right through both devices. We then analyzed the post-procedure exposure in 15 consecutive patients who underwent Iodine125 seed placement for prostate cancer from October 2013 to January 2014. Measurements were performed by the same physicist utilizing a Ludlum Model 14C S/N 80047 survey meter with and without the shield in place at the grid template, which is flush to the perineum, and at the stepper dial, which was 25 cm from the perineum. At both of these locations three measurements were taken: midline, left lateral and right lateral. At the grid the lateral measurements were 10 cm off central axis and at the stepper the lateral measurements were 25 cm off central axis. Endpoints were analyzed using the paired two-sample t-test, with statistical significance defined as a p-value <0.05. Results: The mean exposure at the midline grid template was 37.67 mR/hr (95% CI Z 27.10-48.23) without the shield and 7.98 mR/hr (95% CI Z 5.81-10.15) with the shield (p < 0.0001). The mean exposure 10 cm left of the grid template was 30.73 mR/hr (95% CI Z 22.8-38.67) without the shield and 0.45 mR/hr (95% CI Z 0.28-0.62) with the shield (p < 0.0001). The mean exposure 10 cm right of the grid template was 29.47 mR/hr (95% CI Z 21.68-37.25) without the shield and 0.40 mR/hr (95% CI Z 0.22-0.58) with the shield (p < 0.0001). The mean exposure at the midline, 25 cm from the perineum, was 3.59 mR/hr (95% CI Z 2.82-4.37) without the shield and 0.93 mR/hr (95% CI Z 0.69-1.17) with the shield (p < 0.0001). The mean exposure 25 cm left of midline and 25 cm from the perineum, was 3.31 mR/hr (95% CI Z 2.44-4.17) without the shield and 0.76 mR/hr (95% CI Z 0.57-0.95) with the shield (p < 0.0001). The mean exposure 25 cm right of midline and 25 cm from the perineum, was 3.45 mR/hr (95% CI Z 2.61-4.29) without the shield and 0.75 mR/hr (95% CI Z 0.54-0.96) with the shield (p < 0.0001). The mean reduction of exposure at the grid was 78.8% midline, 98.5% left and 98.6% right. The mean reduction of exposure 25 cm from the perineum was 74.1% midline, 77.0% left and 78.3% right. Conclusions: In this series our novel shield took seconds to install and was non-restrictive during the procedure. In conforming to the As Low As Reasonably Achievable (ALARA) principle, our shield was found to provide at least a four-fold reduction in radiation exposure to the brachytherapist performing the procedure. Author Disclosure: J.P. Weiner: None. D. Schreiber: None. A. Polubruv: None. M. Worth: None. T. Telivala: None. J. Safdieh: None. D. Schwartz: None.

2588 Clinical Experience of Full-Dose External Beam Radiation in Prostate Cancer Patients Failing Initial Treatment With Prostate Brachytherapy M. Meister, M. Rutenberg, P.P. Amin, A. Hussain, M.J. Naslund, and Y. Kwok; University of Maryland School of Medicine, Baltimore, MD Purpose/Objective(s): Patients with prostate cancer (PC) who experience locally recurrent disease after prostate brachytherapy (PB) have limited curative salvage options. We evaluated the efficacy and toxicity of fulldose salvage external beam radiation therapy (EBRT) after PB among men treated at a single institution. Materials/Methods: The entry criteria for this retrospective analysis included patients with: biopsy-proven locally-recurrent PC after prior definitive PB; full-dose salvage EBRT; non-metastatic disease. The Phoenix definition was used for biochemical failure. Estimates of biochemical failure free survival (BFFS) and overall survival (OS) were calculated using the Kaplan-Meier method. Genitourinary function and erectile function were evaluated using the International Prostate Symptom Scores (IPSS) and International Index of Erectile Function scores (IIEF), respectively. Acute toxicities were graded using Common Terminology

Poster Viewing Abstracts S445 Criteria for Adverse Events version 4.03 (CTCAE) while the late toxicities were evaluated via the RTOG-LENT scale. Results: Eleven men with a median age of 67 years (range: 61-81) at the time of salvage were included. Median follow-up was 26.5 months (range: 1.0-53.6). The median time to failure after initial PB was 49.2 months (range: 12.9-135.5). Eight patients (73%) received salvage EBRT that included the whole pelvis, one (9%) received EBRT to the prostate and seminal vesicles only, while two (18%) received EBRT to the prostate only. The median prostate dose for EBRT was 70.2Gy (range: 64.8-75.6). Actuarial three-year overall and biochemical failure free survival were 68% and 61%, respectively. Five patients (45%) had worsening urinary symptoms and nine patients (82%) experienced a decline in erectile function following salvage EBRT. Eight patients (73%) experienced acute grade 1-2 gastrointestinal/genitourinary (GI/GU) toxicities and five patients (45%) experienced late grade 1-2 GI/GU toxicities. One patient developed a urethrorectal fistula requiring an ileostomy and colostomy (grade 3); this patient received a 75.6Gy total dose. No grade 4-5 toxicities occurred. Conclusions: To our knowledge this is the only report to date documenting experience of full-dose EBRT as salvage treatment for locally recurrent PC after PB. Our data suggest salvage EBRT can provide disease control with acceptable treatment-related toxicity in appropriately selected patients, with significant but acceptable morbidity. Author Disclosure: M. Meister: None. M. Rutenberg: None. P.P. Amin: None. A. Hussain: None. M.J. Naslund: None. Y. Kwok: None.

2589 Acute and Late Toxicity of Prostate Radiation Therapy Utilizing Fiducial Versus Cone Beam Computed Tomography Daily Alignment D.M. Harris, A.M. McDonald, and J.B. Fiveash; UAB, Birmingham, AL Purpose/Objective(s): To compare the rates of acute and late gastrointestinal (GI) and genitourinary (GU) toxicity associated with daily alignment to implanted fiducials via kV radiographs versus alignment to the prostate via cone-beam computed tomography (CBCT). Materials/Methods: Two hundred twelve patients with clinically localized prostate cancer treated with hypofractionated prostate radiation therapy (RT) between 2005 and 2011 were included in this analysis. All patients received 70 Gy to the prostate in 28 fractions and 103 patients received simultaneous 50.4 Gy to the pelvic lymph nodes. Daily image-guided alignment was performed either to implanted fiducial markers with kV radiographs or to the prostate or prostate-rectum interface via CBCT. Acute and late GI and GU toxicity were retrospectively scored by the CTCAE 4.0 scale and statistical analysis was performed using IBM SPSS version 22 software. Results: The acute and late (at 3 years) toxicities (CTCAE grade 2 or worse) within each group are presented in the table below.

Scientific Abstract 2589; Table Prostate-only (n Z 109)

Fiducials (n Z 23) CBCT (n Z 86)

P

Acute GI 2 17 .214 Acute GU 11 41 .990 Late GI 3 2 .020 Late GU 2 6 .650 Lymph Nodes treated (n Z 103) Fiducials (n Z 19) CBCT (n Z 84) P Acute GI 7 31 .996 Acute GU 13 41 .122 Late GI 1 13 .383 Late GU 1 7 .842

Conclusions: The acute GU and GI toxicities are similar in patients receiving fiducial-based or CBCT alignment. For patients receiving prostate-only RT, the rate of late GI toxicity was increased for patients with implanted fiducials. Late GU toxicity was not increased for patients receiving fiducial-based alignment despite the inability to evaluate daily bladder filling in this group.