43 Patterns and predictors of acute toxicity after HDR brachytherapy and 3D-CRT for localized prostate cancer: Preliminary results of phase I–II dose escalation study

Proffered pape,'s

SI4 Saturday, 9 June 2001

same position, corregistration (fusion) of the two image sets with a dedicated software, transfer of the new image set to the TPS via DICOM, definition of target and organs at risk (OAR) in the corregistrated (fused) images set and calculation of the definitiv dosimetry. The accuracy of image fusion was quantified by recording the distance between the center of the prostatic urethra on axial MR vs CT images after fusion in each patient. The differences in dosimeric parameters were evaluated using t-Student test. Results: The accuracy of the fusion protocol was high. The average distance between the center of the prostatic urethra on axial MR vs CT scan was lmm (range, 0mm-4mm). The median prostate TRUS volume was 32cc. The median prostate CT volume was 43cc (34% greater). The median prostate CT-MRI was 34cc (2.5% greater). The dosimetric results are shown in the following table:

D90 (1125) V100 V150 V200

CT based PP 150Gy 82% 45% 14%

CT-MRI based PP 156Gy 88% 42% 13%

p value 0,003 0,003 0.110 0,560

Conclusion: image corregistration is a feasible technique for postimplant dosimetric analysis. CT-MRI corregistrated images predict prostate size and morphology with a high degree of accuracy significantly improving accuracy of dosimetry and DVH related parameters providing a more realistic and consistent way of assessing the quality of a prostate seed implant. 40

oral

Urinary retention following ultrasound guided brachytherapy for prostate cancer: incidence and risk factors J.C. B/asko, M. Fisher, P.D. Grimm, W.A. Cavanagh Seattle Prostate/nstitute, Seattle. USA

J.E. Sy/vester. R. Meier,

Purpose: to determine the incidence and possible risk factors associated with urinary retention requiring an indwelling catheter following 125Iodine/103-Palladium brachytherapy for prostate carcinoma. Methods and materials: between November 1999 and March 2000. 242 consecutive men underwent permanent source brachytherapy at our institution as definitive treatment for early stage carcinoma of the prostate. External beam radiation (32%) or neoadjuvant hormonal treatment (34%) were used in addition to brachytherapy at the discretion of the treating physician. All 242 men were sent a one-page questionnaire relating to the need for bladder catheterization because of urinary obstruction postimplant. All men had been followed at least one year following implantation. Results: as of this writing, 175/242 (72%) questionnaires have been returned. Of the 175 respondents, 21 (12%) required bladder catheterization for the treatment of urinary obstruction. Median time of catheter duration was 29 days. Five of the 175 respondents (2.9%) required a catheter longer than three months. Duration of catheterization was as follows: less than 24 hours- 1/175 (1%), 1 day to 1 week- 7/175 (4%), 1 week to 1 month- 4/175 (2%); 1 month to 3 months- 3/175 (2%); 3 months to 6 months- 1/175 (0.5%); greater than 6 months- 4/175 (2%). In univariate analyses, age, isotope type, adjuvant external beam radiation, neoadjuvant hormonal therapy, serum PSA at presentation, stage, prostate volume, number of seeds, number of needles, post-implant dosimetric parameters of Vl00, V150 and D90 were not significantly associated with the need for catheterization. Patients presenting with an I-PSS score of 10 or greater, however, had a 21% rate of catheterization, compared with an 8.6% risk for those with a score of less than 10 (p=0.028). I-PSS score greater than 10 also attained significance on logistic regression (p=0.026), with no other variables achieving significance in the model. Conclusion: this series depicts a 12% rate of urinary retention requiring catheterization following permanent 125-1odine/103-Palladium prostate brachytherapy. An I-PSS symptom score of 10 or greater at presentatioin was associated with a significantly higher risk of retention. 41 oral I o d i n e 125 brachytherapy for prostate cancer. Experience o f

the group Curie-Cochin L. Chauveinc 1, T. Flam2, J.C. Rosenwald 1, P. Araya 1, N. Thiounn 2, F. Firmin 1, B. Debre2, J.M. Cosset 1 l lnstitut Curie, Paris, France 2H6pital Cochin, Paris, France From May 1998 to January 2001, 170 patients were implanted with Iodine 125 seeds for a prostate cancer at the Paris Institute Curie, in collaboration with the urotogy Unit of the Cochin Hospital. Selection criteria were as follows: T1/-F2, PSA _<15, Gleason _<7, and no extra prostatic extension at the

endorectal coil RMI exploration. The dosimetric quality control followed the recommendations of the ABS and the ESTRO, based on the CT-scan evaluation at two months (prescribed dose 145 Gy, D90> 145 Gy). Median age of the patients was 66.5 years (48-80). Median PSA level was 9 ng/ml (1.8-15). 19% of the patients has a Gleason 7 tumors. RapidStrand seeds with the preplanning method were used for the 17 first implantations. Loose seeds with the real time 3 D dosimetry method was used for all the following patients. In the first t7 patients series, only 2 implantations met the AS requirements (D90>145 Gy). For all the other patients, implantations showed a D90>145 Gy with a median value of 183 Gy (145-240). Using RTOG bladder toxicity, 15% of the patients were grade 0, 37% grade 1, 35% grade 2, and 17% grade 3. Only 5 patients (3%) had to keep a temporary bladder catheter. As for the rectal toxicity, 24% of the patients had grade 1 rectal complications, with no patients with grade 2 or 3 toxicities. At 1 year, 71% of the available patients had a PSA level below 1 ng/ml, and 48% below 0.5 ng/ml. Conclusion: after a slightly disappointment for the first series treated with the preplanning technique, probably at least partly due to the "learning curve", all dosimetric results of the 153 bellow patients treated with the loose seeds were satisfactory. Toxicity looks acceptable. Preliminary results are satisfactory, but have to be reconsidered with a longer follow-up. 42

oral

5-year results following conformal HDR brachytherapy (HDRCBT) and elective pelvic irradiation for high-risk prostate cancer (initial PSA > 20 ng/ml): is hormonal therapy beneficial ? R. Galalae, T. Loch, A. Oldorp, N. Ndrnberg, H. Bertermann. P. Niehoff. P. Kohr. B. Kimmig, G. Kovacs Interdisciplinary Brachytherapy Center, Christian-Albrechts-University. KieL Germany Purpose: to report 5-year results of a close escalating protocol using HDRCBT combined with elective irradiation of pelvic lymphatics in men with Iocallly advanced prostate cancer and initial PSA>20 ng/ml and the influence of hormonal ablation. Material and methods: sixty consecutive treated patients were evaluated. The median initial PSA was 34.5 ng/ml (minimum 20 ng/ml). The Iocoregional pelvic lymphatics were treated to 50 Gy by external-beam radiotherapy (EBRT); the close in the prostate was limited to 40 Gy using individual compensators. The prostate was boosted to the nominal total dose of 70 Gy by 2 fractions of transrectal ultrasound (TRUS) guided and preplanned HDR-CBT, which were integrated in the percutaneus series. We segregated the patients in two prognostic groups: group I, n=31 (PSA > 20 ng/ml and grading G1-2 and Gleason < 7) and group II, n=29 (PSA > 20 ng/ml and grading G3 or Gleason > 7). The influence of hormonal therapy was also analyzed. Results and discussion: the median follow-up was 63 months (minimum 24 months). The 5-year bNED survival according to Kaplan-Meier was 59% for the entire cohort with initial PSA > 20 ng/ml. For group I the bNED survival rate was 67.7%, for group II 38%. A significant difference for bNED survival segregating patients by hormonal ablation could not be demonstrated (p=0.17). Hanks et al. (IJROBP 41: 501-10, 1998) reported bNED survival rates of 30% following conformal EBRT at 5 years and dose level > 72 Gy in the same patient cohort (PSA > 20 ng/ml). In comparison with these data the bNED survival in our material seems to be superior with 59%. Stratifying patients in the defined prognostic groups no significant difference was seen in the group I1: Kie139%, Fox Chase 36%. However, in the group I the bNED rate in our material was 68%, while it was 32% in the Fox Chase material. Conclusion: the results confirm, that local dose esclation by HDR-CBT is an effective treatment method especially in men with high-risk advanced prostate cancer. A benefit of adjuvant hormonal ablation could not be demonstrated. 43

oral

Patterns and predictors of acute toxicity after HDR brachytherapy and 3D-CRT for localized prostate cancer: preliminary results of phase I-II dose escalation study A. Raben 1, A. Grebler 1, R. Ivker 2, J. Geltzeiler 1. J. Yang 1. S. Shoengold2, A. Helfman2, D. Raben 3, A. Baron 3, C. Zeng3 1Monmouth Medical Center, Radiation Oncology, Long Branch, USA 2Newark Beth Israel Medical Center, Radiation Oncology, Newark, USA 3University of Colorado Health Science Center, Radiation Oncology, Denver, USA Purpose: To evaluate the patterns of acute gastrointestinal (GI) and genitourinary (GU) toxicity and symptom resolution during the initial 12 months