294 poster CT, MRI, and CT-MRI image fusion assessment for prostate I-125 post implant dosimetry

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symptoms. Only 13.8% had a grade 3 & 4 acute GU symptoms. 15% of our patients suffered of acute urinary retention, being mainly in the acute post-implant phase. All were treated successfully and are being catheter free. Late grade 3 & 4 GU symptoms affected only 1.9% of our population. Regarding GI symptoms, 91.9 % of our population showed to be symptom free in the acute phase, 7.1% had grade 1 and 0.8% had grade 2 GI symptoms. Elapse time reduce GI symptoms, 95.9% of the patients being symptoms free and 4.1% had residual grade 1 at 6 months post implantation. Conclusion: Inverse planning and high activity seeds (average of 60 seeds/patient) gives a 5 year PSA failure free survival comparable with the best published series with a low toxicity profile for patients with localized prostate cancer treated with I 125 permanent prostate implant. 292 poster Can we accrue to "difficult" trials in brachytherapy?

J. Crook ~, K. Wallace 1, N. Fleshnef , M. Jewetl2 IPrincess Margaret Hospital, Radiation Oncology, Toronto, Canada 2University Health Network, Urology, Toronto, Canada Purpose: In order to improve accrual to difficult randomized trials, innovative methods are required. Trials comparing brachytherapy to another treatment option (surgery or external radiation) may not seem equivalent in a patient's mind. SPIRIT (ACOSOG Z0070* NCIC PR10: radical prostatectomy vs. brachytherapy for favourable risk prostate cancer) is a good example of such a trial. We describe the results of a program of educating patients and their families about early stage, favourable prostate cancer and their treatment options and the impact of these sessions on trial accrual. Materials and Methods: We developed a 90 minute education session for SPIRIT candidates and their families. All new prostate referrals are screened by the Clinical Research Associate (CRA) using SPIRIT criteria and eligible patients are contacted prior to their first consult at the multidisciplinary urooncology clinic and invited to a small group educational session which is held weekly. This session, facilitated by the clinical research associate (CRA), begins with the SPIRIT informed consent video followed by presentation from a patient and SPIRIT participant who describes his decision-making process. A radiation oncologist and urologist then jointly compare and contrast RP and BT and establish the rationale and purpose behind the trial. Emphasis is placed upon the clinical equipoise that exists between these modalities by the radiation oncologist and urologist. Trial-specific, but not patient-specific, questions are answered. Consult appointments are verified, patients are given a SPIRIT brochure, and CRA contact information. Results: Prior to initiating this approach, 27 eligible patients over a 3 month period were offered SPIRIT in the standard fashion by the urologist or radiation oncologist and none consented. After commencing the educational intervention, 198 patients have attended a session and 32 have consented to the trial (chi square=3.863, p<0.05). Consent rates since the launch of the evening sessions now approach 1 in 6. Conclusion: These data support the efficacy of a novel approach using a small group educational session in improving accrual to SPIRIT. They also confirm that obtaining informed consent for challenging trials involving brachytherapy is feasible. Sites open to SPIRIT but having difficulty with accrual, or new sites taking on the trial, may want to consider this method.

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293 poster 1125 re-implantation in patients with poor initial dosimetry after prostate brachytherapy

M. Keyes ~, T. Pickles ~, A. Agranovich 2, W. Kwan2, J. Morris 1 ~BC Cancer Agency, Vancouver Cancer Centre, Radiation Oncology, Vancouver BC, Canada 2BC Cancer Agency, Fraser Valley Cancer Centre, Radiation Oncology, Surrey BC, Canada Purpose: To present dosimetric and clinical parameters on 9 patients with suboptimal dosimetry after 1-125 prostate brachytherapy, who underwent a second re-implant procedure in order to improve dosimetric coverage of the prostate. Material and methods: Between July 1998 and January 2004, 1050 patients were implanted at Vancouver Cancer Centre. Low risk patients (GS< 6; PSA_< 10 and < T2a) received implant alone. Patients with prostate volume >50cc, GS 7, or PSA 1015, received 3 months of neoadjuvant hormones, brachytherapy and 3 months of adjuvant hormones. Mean V100 and D90 for entire group is 91.2% and 151 Gy. Nine pts (0.85%) have undergone a second re-implant procedure to improve dosimetric coverage of the prostate. Results: Median FU of re-implanted pts is 6 months (range 224). The pre-treatment characteristics: clinical stage, Gleason Score, iPSA, location of positive cores, IPSS, potency, use of androgen suppression, are described. Median time to reimplant is 64 days (range 54-110). Initial implant median V100 and D90 (Day 30 CT- based post implant dosimetry) are 74% (range 59-82%)and 110Gy (70-122Gy). Re-implant median V100 and D90 (Day 0 CT based post implant dosimetry) are 96% (range 90-99%) and 168Gy (range 144196Gy). Median rectal volumes receiving 100% of the dose (VR100) for the initial vs. re-implant are 1.03 vs. 1.7 cc. Short term PSA outcome is favourable, median PSA post treatment is 0.19 (range 0.17-0.62). Re-implanted patients had transient increase in IPSS scores and acute grade 2 urinary toxicity. One pt had transient worsening of the mild rectal symptoms. The acute toxicity of the re-implant procedure has been reasonably low. We describe our re-implant planning and intra-operative procedure. Conclusion: It is possible to safely add more seeds to the dosimetricaly cool area after the initial brachytherapy procedure and achieve excellent post-implant dosimetry with acceptable acute toxicity the second time around. So far, the available data on dose response in prostate brachytherapy may justify this approach. The ultimate benefits and long term toxicity of reimplantation is unknown. 294 poster CT, MRI, and CT-MRI image fusion assessment for prostate 1-125 post implant dosimetry

B. AI-Qaisieh 1, B. Carey2, J. Evans3, A. Flynn ~, D. Bottomley 4, D. Ash" ~Cookridge Hospital, Medical physics, Leeds, United Kingdom 2Cookridge Hospital, Radiology, Leeds, United Kingdom 3Cookridge Hospital, University of Leeds, Leeds, United Kingdom 4Cookridge Hospital, Radiation Oncology, Leeds, United Kingdom Purpose: (1) To validate the use of CT and MRI for post implant dosimetry (2) To quantify the uncertainty in outlining the prostate and the precision of identifying seeds on CT and MRI. Methods and materials: Sixty two patients had CT and MRI scans 53 days (average) after the implant procedure. Two experienced observers were each asked to contour the prostate margins on six patients six times at weekly intervals. To

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compare the six trials, a computer program was generated to identify the pixel numbers and positions which were included in the prostate outline. The same two observers were also asked to identify seeds of another three patients on CT and MRI. Dose Volume Histograms (DVHs) were calculated to report the Implant, Prostate, and Rectum quality indices. CT, MRI, and CT-MRI image fusion were used individually to perform post implant dosimetry for 62 patients. Prostate, rectum, urethra, and seeds were defined by the agreement of the two observers. DVHs were calculated to report quality indices such as D90. Variations of observers and imaging modalities were compared. Results: The results of this study suggest that inter- and intra observer variability is significant on both CT and MRL The level of observer uncertainty outlining the prostate on MRI is less than CT by 6.7%. Overall, the uncertainty of outlining the prostate is 30.2% of the prostate on CT and 23.4% on MRI. The highest uncertainty (48.7% and 36.8% on CT and MRI respectively) was found in the apex area of the prostate. The lowest (21.1% and 16% on CT and MRI respectively) was in the middle section. Seed identification variability due to observer and imaging modality differences on CT and MRI has shown no significant difference based on the outcome of implant dosimetry although discrepancy on MRI was higher. Comparison of dosimetry outputs from CT-MRI image fusion with CT shows no significant difference. D90 difference is 1.1% _+ 2.2%. However, a significant difference is evident when comparing CT-MRI fusion and MRI DVHs. D90 difference is 11.9% _+5.8%. Conclusion: MRI can improve observer accuracy in Outlining the prostate by an average of 6.7% compared with CT. However, when fused with CT images, this improvement has no significant effect on the post implant dosimetry quality indices in comparison with CT alone. MRI, however, is still a valuable tool for learning about prostate anatomy. 295 poster

Androgen deprivation-induced changes in prostate anatomy predict urinary morbidity following permanent interstitial brachytherapy D. Reed ~, G. Merrick z'3, A. Hinerman-Mulroy 2, W. Butler 2"3,K. Wallner ~, Z. Allen 2, E. Adamovich 4 ~University of Washington School of Medicine, Department of Radiation Oncology, Seattle, U.S.A. 2Wheeling Hospital, Schiffler Cancer Center, Wheeling, U.S.A. 3Wheeling Jesuit University, Department of Physics, Wheeling, U.S.A. 4Wheeling Hospital, Department of Pathology, Wheeling, U.S.A. Purpose: To evaluate the cytoreductive consequences of neoadjuvant androgen deprivation therapy on International Prostate Symptom Score (I-PSS) normalization, catheter dependency, and the need for surgical intervention secondary to bladder outlet obstruction following permanent interstitial brachytherapy. Materials and Methods: One hundred sixteen patients (median follow-up 30 months) with pre- and post-androgen deprivation therapy ultrasound studies and no history of a preimplant transurethral resection (TURP) were evaluated. Androgen deprivation-induced changes in prostate volume, transition zone (TZ) volume and urethral location were correlated with t-PSS resolution, catheter dependency and the need for post-implant surgical intervention. Prostate gland and TZ dimensions and volumes were measured by prolate ellipsoid calculation from the static ultrasound images. The urethral location was determined by identification of a urinary catheter. Additional clinical, treatment and dosimetric parameters evaluated included patient age, pretreatment PSA, Gleason score, clinical T-stage, preimplant I-PSS, pre- and post-

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androgen deprivation ultrasound studies, treatment planning volume, supplemental external beam radiation therapy (XRT), isotope, total implant activity, day 0 Dg0 and V~oo~so~2o0,and urethral dose.

Results: For hormonally manipulated patients, prostate volume at the time of implantation did not statistically impact the percent of patients returning to I-PSS baseline, the time for tPSS normalization, the incidence of catheter dependency, days of catheter dependency or the need for post-implant surgical intervention. However, when compared to the hormone-na'ive cohort, hormonally manipulated patients were more likely to undergo post-implant surgical intervention (5.2% versus 0.3%, p = 0.001). Greater androgen deprivation-induced reductions in prostate and TZ volumes along with movement of the urethra closer to the posterior border of the prostate gland resulted in a decreased incidence of post-implant urinary morbidity. By means of a Cox regression analysis, time to I-PSS resolution was best predicted by percent TZ volume reduction. Stepwiselinear regression demonstrated that days of catheter dependency was best predicted by pre-hormone prostate volume, post-hormone TZ volume and change in urethral position; prolonged catheter dependency by percent TZ volume reduction, pre-hormone TZ index and change in urethral position; and the need for post-implant surgical intervention by post-hormone TZ index and change in urethral location. Conclusion: Following neoadjuvant androgen deprivation therapy for volume reduction, some brachytherapy- related urinary morbidity parameters are highly related to pre-androgen deprivation prostate volume, variants of the TZ volume and changes in urethral location. 296 poster

Permanent interstitial brachytherapy for younger patients with clinically organ-confined prostate cancer D. Reed I, G. Merrickz's, W. But/etz'~, K. Wa//ner~, R. Ga/breath2, E. Adamovich 4 I University of Washington School of Medicine, Department of Radiation Onco/ogy, Seattle, U.S.A. 2Whee/ing Hospital, Schiff/er Cancer Center, Wheeling, U.S.A. 3Whee/ing Jesuit University, Department of Physics, Wheeling, U.S.A. 4Wheeling Hospital, Department of Pathology, Wheeling, U.S.A. Purpose: To evaluate biochemical progression-free survival in hormone-na'ive men < 62 years of age with clinically organconfined prostate cancer who underwent brachytherapy with or without supplemental external beam radiation therapy (XRT). Materials and Methods: From April 1995 through December 2000, 119 hormone-na'(ve patients < 62 years of age underwent permanent interstitial brachytherapy for clinical Tlb-T2c NxM0 (2002 AJCC) prostate cancer. No patient underwent seminal vesicle biopsy or pathologic lymph node staging. The median follow-up was 4.7 years (range 2.6 - 8.3 years). Biochemical progression-free survival was defined by either a PSA < 0.4 ng/mL after a nadir or by the ASTRO consensus definition. No patient was lost to follow-up. Clinical, treatment and dosimetric parameters evaluated for biochemical progression-free survival included age, clinical T-stage, Gleason score, pretreatment PSA, risk group, percent positive biopsies, isotope, supplemental XRT, prostate volume, brachytherapy planning volume, the percent of the target volume receiving 100%, 150%, and 200% of the prescribed dose (V~o0/~s0/2o0),the minimum percent of the prescribed dose covering 90% of the target volume (Dgo),and tobacco status. Results: For the entire group, actuarial 7-year biochemical progression-free survival was 96.1% and 98.3% for a PSA cutpoint _< 0.4 ng/mL or the ASTRO consensus definition respectively. Using a PSA biochemical control definition of _<0.4