I. J. Radiation Oncology
● Biology ● Physics
Volume 63, Number 2, Supplement, 2005
symptom subscales there was an increase in reported sleep symptoms and increased GI symptoms. In the PR25 questionnaire, of the 52 patients reporting sexual activity at baseline, 37 (71%) were reporting no sexual activity by the 4-month post treatment evaluation (more mature follow-up recovery data will be presented). We will report in detail the serial changes in the EORTC QoL questionnaire and will relate these results with the toxicity profiles. Conclusions: A recent trial by D’Amico et al. (2004) showed improved survival using TAB androgen deprivation compared to radiation therapy alone in pts with intermediate/high PC. Six months of TAB using Casodex and Zoladex is well tolerated with 94% of patient in the current study having completed the treatment program. Based on the current, published literature, Casodex appears to have a more favorable side effect profile than other nonsteroidal anti-androgens.
Intraoperative Prostate Brachytherapy: Does Real-Time Ultrasound-Based Dosimetry Obviate the Need for Post Implant Dosimetric Analysis? A Retrospective Analysis of 1100 Patients Treated at Kaiser Permanente of Northern California
A. Mahmoudieh, L.B. Goldman, M. Russo, D. Chabra, S. Workman, D. Lindstat Radiation Oncology, Kaiser Permanente, Roseville, CA Purpose/Objective: Currently the standard of care for permanent prostate brachytherapy is to perform post-implant dosimetry several weeks after the implantation. In this retrospective study we compared the two dosimetry data sets (US obtained at the time of the implant and CT 1 month post-implant) to evaluate how predictive dosimetry data obtained at the time of implant (US) is to CT. If we can show there is good correlation between the two, can post implant dosimetry be eliminated? Materials/Methods: Methods and Material: Between August 2000 and June 2004, a total of 1175 Patients were treated for early stage prostate cancer. Loose I 125 seed implantation via intra-operative planning modality was utilized for all patients. The mean patients age was 62 years. Only 81(6.9%) of the Patients had Gleason 7 and rest were all ⬍ 7 (80% had Gleason 6). Most patients had stage T1c, 81.4%. Stage T2a was noted on 139 (11.8%) of the patients, and only 13 Patients had stage T2b. Five hundred thirty nine of these patients had pre-planning prior to the implant, however they did undergo Intra-operative Dosimetry (IOD) for adjustment and optimization. Real-time US-based dosimetry was performed for all patients using Variseed software. Post-implant dosimetry was performed by CT 4 weeks after the implant. The percentage of the prostate volume receiving 100% of the dose (V100) along with V150 and V200 and the minimal dose to 90% of the outline volume (D90) were calculate and compared. Results: The mean prostate volume CT-based and US-based was 46.6 cc and 37.5 cc respectively. The mean V100 for CT-based/ US-based ratio was 0.94. For 94% of the patients the difference of the V100 and V150 between the CT -based, US-based was ⬍10%. The mean D90 for CT-based dosimetry was found to be 160 Gy. The CT-based V100 for all patients were ⬎92%. Conclusions: Our result indicates that the dosimetry obtained intra-operatively including V100, V150, D90 with our real-time US-based are in reasonable agreement with the subsequent values obtained with CT-based dosimetry performed 4 weeks post-implant. The ABS recommendation that postoperative dosimetry to be performed for all patients may need to be reviewed with the more utilization of intra-operative planning. Prostate Dosimetry Data
Influence of Preimplant International Prostate Symptom Score on Urinary Morbidity Following Prostate Brachytherapy
S. Gutman,1 G. Merrick,1,2 W. Butler,1,2 K. Wallner,3 Z. Allen,1,2 R. Galbreath1,4 Schiffler Cancer Center, Wheeling Hospital, Wheeling, WV, 2Wheeling Jesuit University, Wheeling, WV, 3Group Health Cooperative, Puget Sound Veterans Administration, and University of Washington, Seattle, WA, 4Ohio University Eastern, St. Clairsville, OH 1
Purpose/Objective: To determine if the preimplant International Prostate Symptom Score (IPSS), stratified into mild (0 –7), moderate (8 –19), and severe (⬎ 20) categories, predicts for brachytherapy-related morbidity in terms of IPSS resolution, catheter dependency and the need for postbrachytherapy surgical intervention. Materials/Methods: From January 1998 through September 2003, 1,034 consecutive patients underwent permanent interstitial brachytherapy for clinical stage T1b-T3a NxM0 (2002 AJCC) prostate cancer. Of the 1,034 patients, 739 (71.5%) presented with an IPSS of 0 –7, 287 (27.7%) with an IPSS of 8 –19, and 8 (0.8%) with an IPSS ⬎ 20. The IPSS 8 –19 cohort was further stratified into 8 –14 (n ⫽ 237) and 15–19 (n ⫽ 50) subgroups. The median follow-up was 38.2 months. In all patients, an alpha blocker was initiated prior to brachytherapy and continued at least until the IPSS normalized. A median of 21 IPSS questionnaires were obtained per patient. Clinical, treatment and dosimetric parameters evaluated for urinary morbidity included preimplant IPSS, patient age, pretreatment PSA, Gleason score, clinical T stage, percent positive biopsies, ultrasound volume, planning volume, isotope, D90, V100/150/200, urethral dose (average and maximum), supplemental XRT, androgen
Proceedings of the 47th Annual ASTRO Meeting
deprivation therapy (ADT), and the duration of ADT (ⱕ 6 months versus ⬎ 6 months). The incidence of catheter dependency and the need for postimplant surgical intervention were also evaluated. Results: For the entire cohort, the IPSS on average peaked 1 month following implantation with IPSS resolution at a mean of 4 months. Five year actuarial results demonstrated that 85.6% of all patients (88.6%, 78.4%, and 62.5% of patients with a preimplant IPSS of 0 –7, 8 –19, and ⬎ 20 respectively) were within the IPSS 0 –7 category. Compared to the preimplant IPSS, 75 patients (7.3%) were assigned to a higher IPSS severity category. Neither prolonged urinary catheter dependency (⬎ 5 days) (16 patients, 1.5%) or transurethral resection (17 patients, 1.7%) were dependent on preimplant IPSS subgroup. In Cox regression analysis, IPSS resolution was best predicted by preimplant IPSS; prolonged catheter dependency by patient age; and postimplant TURP by any catheter dependency, the maximum IPSS increase and the maximum urethral dose. Conclusions: Preimplant IPSS, when stratified into mild, moderate or severe categories, did not predict for substantial urinary morbidity to include prolonged IPSS elevation, catheter dependency or the need for postbrachytherapy TURP. At 5 years following brachytherapy, 85.6% of patients were within the IPSS 0 –7 category regardless of preimplant IPSS.
Does a Delay in Low Dose Rate (LDR) Brachytherapy After Tissue Diagnosis Affect Outcome for Men with Low Risk Prostate Cancer?
S.F. Andrews,1 E.M. Horwitz,1 S.J. Feigenberg,1 D.F. Eisenberg,1 R.G. Uzzo,2 A. Pollack1 Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA, 2Surgery, Fox Chase Cancer Center, Philadelphia, PA
Purpose/Objective: A treatment delay for prostate cancer has the potential to increase tumor bulk, increase the likelihood of microscopic extension of disease beyond the prostate, spread to local/regional lymph nodes or to distant sites. This may impact clinical outcome where sharp radiation dose gradients exist and can influence implant quality. To our knowledge there is no data to guide physicians on the urgency implant after diagnosis. Materials/Methods: One hundred and thirteen low risk prostate cancer patients treated from 05/98 to 12/02 with permanent I-125 prostate implants alone were analyzed. The median PSA was 6.1. AJCC 2002 palpation stage was T1c, T2a and Tx in 83, 23 and 1 patient respectively. Three patients were Gleason score 7 and the remaining 106 patients were Gleason scores 2– 6. No patients received neoadjuvant or adjuvant androgen deprivation as part of their initial management. Median follow-up was 35 months (12–74). Time to implant (TTI) was defined as the interval from first positive biopsy to LDR implant. Patients were categorized above and below the median TTI for analysis. A second analysis was performed dividing patients into quartiles with respect to TTI. Freedom from biochemical failure (FFBF) was calculated for all patients. FFBF was defined according to the ASTRO definition. MVA stepwise Cox proportional analysis was also performed use TTI, prescription dose, PSA, T Stage and D90 (day 30) as predictors of outcome. Results: Median TTI was 4.3 months (1.5–17.9). The 5 year estimates of FFBF were 95% and 86% (p⫽0.1503) for patients treated less than or greater than the median TTI. When patients were divided into quartiles there again was no significant effect of TTI on FFBF. Finally, TTI, prescription dose, PSA, T Stage and D90 did not predict for outcome on MVA. Conclusions: To our knowledge these preliminary findings are the first to show that a delay in time to implant from the date of diagnosis does not alter clinical or biochemical outcome. Patients and physicians can use this information to alleviate concerns over delaying LDR brachytherapy alone in order to make well informed treatment decisions. Longer follow-up with larger patient numbers are needed to confirm these findings.
Pelvic Field Size and Biochemical Failure in the Treatment of Prostate Cancer: A Single Institution Experience
D.E. Soto,1 D. Kempien,1 M. Schipper,2 A. Meirovitz,1 H.M. Sandler,1 M.E. Ray,1 C.C. Pan1 Radiation Oncology, University of Michigan, Ann Arbor, MI, 2Biostatistics, University of Michigan, Ann Arbor, MI
Purpose/Objective: For localized prostate cancer patients with a high risk of lymph node involvement, a recent RCT (RTOG 9413) has shown an improvement in progression free survival with external beam radiation that included pelvic nodes compared to prostate alone external beam treatment. In clinical practice, two pelvic field size designs are in use. Whole pelvic field (WP) utilizes an upper boarder set at L5/S1, while the mini-pelvic field (MP) utilizes an upper border set at the inferior aspect of the sacral-iliac joint with the goal of reducing potential GI toxicity. Currently little information exists examining the impact of pelvic field size on clinical outcomes. In this IRB-approved retrospective study, we evaluate the effect of different pelvic field sizes on biochemical failure in patients undergoing definitive radiation therapy for prostate cancer. Materials/Methods: Patients were identified through our institutional prostate cancer data base if they had T1-4 N0-x M0 prostate cancer treated with 3 Dimensional Conformal Radiation Therapy (3DCRT) utilizing a pelvic field between June 1987 and July 2000. Patients were treated with a median pelvic dose of 45 Gy in 1.8 Gy fractions. Using a definition of biochemical failure as a rise of 2ng/ml or more above current nadir a traditional Cox model was utilized to establish the hazard ratios between the two groups. A multivariate analysis was carried out to determine which factors predict for biochemical failure. Results: There were a total 200 patients: 61 MP and 139 WP. Median age was 69 yrs. There were 21.4% T1b-c, 20.4% T2a, 24.4% T2b, 20.4% T2c, 13.4% T3. Gleason scores (GS) ranged from 3–9 with 28.4% 3– 6, 54.2% 7, 17.4% 8 –9. MP and WP patients had a mean pretreatment PSA and mean final dose of 16.5ng/ml, 74.6Gy and 26.2ng/ml, 70.3Gy respectively. 42.6% of MP and 18% of WP received androgen deprivation therapy (ADT). With a median of 41 months PSA follow up (range 1 to 171 mo), 39.5% of this cohort had documented PSA failures: 13/61 (21.3%) MP and 66/139 (47.4%) WP. At the time of this analysis, median PSA failure-free survival for the entire cohort and WP were 93 mo and 69.6 mo respectively. It had not yet been reached for MP. A hazard ratio of 0.52 (p⫽0.085) in favor of WP was noted. Multivariate analysis revealed that dose