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Postimplant Segmental Dosimetry, Biochemical Relapse, and Toxicity in Patients With Prostate Cancer Treated With Loose Iodine-125 Seeds
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Volume 96 Number 2S Supplement 2016 International Index of Erectile Function (IIEF-5) and International Prostate Symptom Score (IPSS) questionnaires, respectively. Results: The median patient age was 56 years (range, 27-59) and followup was 7.3 years. Overall, 48, 34, and 31 men were classified as low, intermediate and high risk, respectively, according to National Comprehensive Cancer Network (NCCN) guidelines. The 5- and 10-year overall survival (OS) rates for the entire cohort were 94% and 88%, respectively. The 5-year biochemical PFS rates for the low-, intermediate-, and high-risk groups were 100%, 97%, and 77%, respectively; at 10 years, they were 93%, 92% and 70%, respectively. Multivariate analysis revealed that African American race (hazard ratio 3.0; 95% CI, 1.2-8.0; P Z 0.023) and receiving ADT (hazard ratio 5.0; 95% CI, 2.0-10.0; P Z 0.001) statistically impacted biochemical failure. Acute GU and lower GI grade 3 or greater toxicities occurred in 3 (3%) and 3 (3%) patients, respectively. Late GU and lower GI grade 3 or greater toxicities occurred in 6 (5%) and 7 (6%) patients, respectively. Two patients (2%) experienced a secondary malignancy. The median post-RT IPSS score was increased by 1 (range, 20-33). IIEF-5 scores remained above 20 in 47% of men who reported preRT erectile function, without necessity of medications. Conclusion: Our results further validate radiation therapy as an effective and safe curative treatment option in men <60 years with localized prostate cancer. Author Disclosure: S. Zhu: None. J. Syed: None. A.L. Holtzman: None. C.G. Morris: None. P. Crispen: None. L. Su: None. R.A. Zlotecki: None.
2649 Postimplant Segmental Dosimetry, Biochemical Relapse, and Toxicity in Patients With Prostate Cancer Treated With Loose Iodine-125 Seeds E. Okazaki,1 K. Ishii,2 M. Hosono,1 R. Ogino,2 S. Tsutsumi,1 and Y. Miki1; 1 Dept of Radiation Oncology, Osaka City University Graduate School of Medicine, Osaka, Japan, 2Tane General Hospital, Osaka, Japan Purpose/Objective(s): The purpose of this study was to identify how postimplant segmental dosimetry affects the biochemical relapse and toxicity of prostate cancer treated with loose iodine-125 seeds. Materials/Methods: We retrospectively analyzed 130 consecutive patients treated for low- (68 patients) and intermediate-risk (62 patients) prostate cancer receiving definitive iodine-125 brachytherapy between January 2008 and December 2014 at our institution. The prescription dose to the whole prostate was 145 Gy. All patients underwent postimplant computed tomography imaging for dosimetric analysis at median 34 days (range 21e168 days) after treatment. Prostate contours were divided into quadrants: anterior-superior (ASQ), posterior-superior (PSQ), anterior-inferior (AIQ), posterior-inferior (PIQ). Dose volume analysis was performed for the whole prostate, each quadrant, urethra and rectum. Univariate and multivariate Cox regression analyses were performed to identify predictive factors for biochemical failures. Statistical comparison of the dosimetric parameters was done using the t-test and one-way ANOVA (Tukey HSD for post hoc testing). Results: The median follow-up was 53.3 months (range 8.4-94.2 months). The mean D90 (the minimal dose received by 90% of the volume) and V100 (the percentage of prostate volume that received a dose equal to or greater than the prescription dose) for the whole prostate was 161.9 Gy and 92.9%. The mean D90 95% confidence for the ASQ, PSQ, AIQ and PIQ were 159.5 39.0 Gy, 172.6 37.0 Gy, 193.6 35.8 Gy and 175.2 36.7 Gy. D90 of ASQ was significantly lower than that of other segments and D90 of AIQ was significantly higher than that of others. Seven patients (5.4%) had biochemical failure. None of the patients died during the follow-up period. Five-year biochemical progression-free survival (bNED) in low- and intermediate-risk group were 97.1% and 88.1%, respectively. Gleason score, prostate-specific antigen, and D90 of PSQ were significant predictive factors of biochemical failure in a multivariate analysis (P Z 0.009, 0.014 and 0.013, respectively). D90 of PSQ and the rectal volume that received 100% of the prescription dose (RV100) were significantly
higher in patients with rectal bleeding than in those without bleeding (P Z 0.036 and 0.008, respectively). There is no significant difference in dosimetric parameters of each quadrant and urethra associated with urinary dysfunction and hematuria. Conclusion: Postimplant D90 of PSQ was a significant predictive factor of biochemical failure and rectal bleeding. We could not demonstrate a correlation of dosimetric parameters of each quadrants and urethra with urinary toxicities. Author Disclosure: E. Okazaki: None. K. Ishii: None. M. Hosono: None. R. Ogino: None. S. Tsutsumi: None. Y. Miki: None.
2650 Early Efficacy of 68ga-PSMA Ligand Positron Emission Tomography/ Computed TomographyeBased Radiation Treatment in Locally Recurrent and Oligometastatic Prostate Cancer After Primary Therapy C. Henkenberens,1 F. Bengel,2 H.J. Wester,3 H. Christiansen,4 and T. Derlin2; 1Hannover Medical School, Department of Radiation Oncology, Hannover, Germany, 2Hannover Medical School, Department of Nuclear Medicine, Hannover, Germany, 3Technical University of Munich, Pharmaceutical Radiochemistry, Munich, Germany, 4Hannover Medical School, Department of Radiation Oncology, Hannover, Germany Purpose/Objective(s): Assessment of early efficacy 68 eof PSMA-PET / CT-based radiation therapy for locally recurrent or oligometastatic prostate cancer after primary therapy. Materials/Methods: Nineteen patients (18/19 (94.7%) with a high-risk carcinoma) presented with biochemical PSA failure after definitive therapy and received additionally to the conventional staging a 68Ga-PSMA PET / CT scan. PET-positive lesions outside the prostate bed received a normofractionated 3D conformal radiation therapy with a dose of 50-54 Gy. PET-positive lesions in the prostate bed were treated with a dose of 66 Gy in VMAT technique. All patients had regular follow-up visits on a three months basis. Any increase in PSA levels above the baseline level three months after radiation therapy triggered a new PSMA-PET / CT scan. Androgen deprivation therapy (ADT) was continued during radiation therapy, but was not initiated in patients who had no ADT. Systemic therapy was only initiated in case of biochemical failure after radiation therapy in patients with an ADT. All cases were approved by local urooncological board. Results: All patients (n Z 19), 100%) presented with a pathological tracer uptake. The PSMA-PET / CT showed that 15.8% (n Z 3) had local recurrence in the prostate bed, 47.6% (n Z 9) had isolated pelvic lymph node metastasis and 26.3% (n Z 5) had isolated bone metastases. One patient (5.3%) had pelvic lymph node metastases and one bone metastases. The median follow-up was 5.8 months (range, 3.0-12.9). The median PSA level before irradiation was 1.3 ng / ml (range, 0.52 - 32.01) and decreased statistically significant to 0.31 (range, <0.07 to 4.23; P <0.001) at the last follow-up visit. One patient (5.3%) with a PSA increase above the baseline level 12.7 months after irradiation showed new PSMA PET positive paraaortic lymph nodes outside the former radiation field. He declined an ADT and he received radiation therapy of the PET positive paraaortic lymph nodes. At the median follow-up of 5.7 months a biochemical progression-free survival (BPFS) and distant disease-free survival (DDFS) of 100% was observed. Furthermore no grade III acute toxicities according to CTCAE or late toxicity grade II according to the LENT-SOMA criteria were observed. A total of 10.6% (n Z 2) reported about a persistent diarrhea grade I without impairing fecal continence. Conclusion: These early results showed that a 68Ga-PSMA PET / CTbased radiation therapy yields effective local control, significantly improved the PSA kinetics, delayed the initiation of chemotherapy in patients with ADT or can defer ADT in ADT-naive patients. Moreover, this treatment is not associated with clinically relevant late side effects. Author Disclosure: C. Henkenberens: None. F. Bengel: None. H. Wester: None. H. Christiansen: None. T. Derlin: None.
Volume 96 Number 2S Supplement 2016 International Index of Erectile Function (IIEF-5) and International Prostate Symptom Score (IPSS) questionnaires, respectively. Results: The median patient age was 56 years (range, 27-59) and followup was 7.3 years. Overall, 48, 34, and 31 men were classified as low, intermediate and high risk, respectively, according to National Comprehensive Cancer Network (NCCN) guidelines. The 5- and 10-year overall survival (OS) rates for the entire cohort were 94% and 88%, respectively. The 5-year biochemical PFS rates for the low-, intermediate-, and high-risk groups were 100%, 97%, and 77%, respectively; at 10 years, they were 93%, 92% and 70%, respectively. Multivariate analysis revealed that African American race (hazard ratio 3.0; 95% CI, 1.2-8.0; P Z 0.023) and receiving ADT (hazard ratio 5.0; 95% CI, 2.0-10.0; P Z 0.001) statistically impacted biochemical failure. Acute GU and lower GI grade 3 or greater toxicities occurred in 3 (3%) and 3 (3%) patients, respectively. Late GU and lower GI grade 3 or greater toxicities occurred in 6 (5%) and 7 (6%) patients, respectively. Two patients (2%) experienced a secondary malignancy. The median post-RT IPSS score was increased by 1 (range, 20-33). IIEF-5 scores remained above 20 in 47% of men who reported preRT erectile function, without necessity of medications. Conclusion: Our results further validate radiation therapy as an effective and safe curative treatment option in men <60 years with localized prostate cancer. Author Disclosure: S. Zhu: None. J. Syed: None. A.L. Holtzman: None. C.G. Morris: None. P. Crispen: None. L. Su: None. R.A. Zlotecki: None.
2649 Postimplant Segmental Dosimetry, Biochemical Relapse, and Toxicity in Patients With Prostate Cancer Treated With Loose Iodine-125 Seeds E. Okazaki,1 K. Ishii,2 M. Hosono,1 R. Ogino,2 S. Tsutsumi,1 and Y. Miki1; 1 Dept of Radiation Oncology, Osaka City University Graduate School of Medicine, Osaka, Japan, 2Tane General Hospital, Osaka, Japan Purpose/Objective(s): The purpose of this study was to identify how postimplant segmental dosimetry affects the biochemical relapse and toxicity of prostate cancer treated with loose iodine-125 seeds. Materials/Methods: We retrospectively analyzed 130 consecutive patients treated for low- (68 patients) and intermediate-risk (62 patients) prostate cancer receiving definitive iodine-125 brachytherapy between January 2008 and December 2014 at our institution. The prescription dose to the whole prostate was 145 Gy. All patients underwent postimplant computed tomography imaging for dosimetric analysis at median 34 days (range 21e168 days) after treatment. Prostate contours were divided into quadrants: anterior-superior (ASQ), posterior-superior (PSQ), anterior-inferior (AIQ), posterior-inferior (PIQ). Dose volume analysis was performed for the whole prostate, each quadrant, urethra and rectum. Univariate and multivariate Cox regression analyses were performed to identify predictive factors for biochemical failures. Statistical comparison of the dosimetric parameters was done using the t-test and one-way ANOVA (Tukey HSD for post hoc testing). Results: The median follow-up was 53.3 months (range 8.4-94.2 months). The mean D90 (the minimal dose received by 90% of the volume) and V100 (the percentage of prostate volume that received a dose equal to or greater than the prescription dose) for the whole prostate was 161.9 Gy and 92.9%. The mean D90 95% confidence for the ASQ, PSQ, AIQ and PIQ were 159.5 39.0 Gy, 172.6 37.0 Gy, 193.6 35.8 Gy and 175.2 36.7 Gy. D90 of ASQ was significantly lower than that of other segments and D90 of AIQ was significantly higher than that of others. Seven patients (5.4%) had biochemical failure. None of the patients died during the follow-up period. Five-year biochemical progression-free survival (bNED) in low- and intermediate-risk group were 97.1% and 88.1%, respectively. Gleason score, prostate-specific antigen, and D90 of PSQ were significant predictive factors of biochemical failure in a multivariate analysis (P Z 0.009, 0.014 and 0.013, respectively). D90 of PSQ and the rectal volume that received 100% of the prescription dose (RV100) were significantly
higher in patients with rectal bleeding than in those without bleeding (P Z 0.036 and 0.008, respectively). There is no significant difference in dosimetric parameters of each quadrant and urethra associated with urinary dysfunction and hematuria. Conclusion: Postimplant D90 of PSQ was a significant predictive factor of biochemical failure and rectal bleeding. We could not demonstrate a correlation of dosimetric parameters of each quadrants and urethra with urinary toxicities. Author Disclosure: E. Okazaki: None. K. Ishii: None. M. Hosono: None. R. Ogino: None. S. Tsutsumi: None. Y. Miki: None.
2650 Early Efficacy of 68ga-PSMA Ligand Positron Emission Tomography/ Computed TomographyeBased Radiation Treatment in Locally Recurrent and Oligometastatic Prostate Cancer After Primary Therapy C. Henkenberens,1 F. Bengel,2 H.J. Wester,3 H. Christiansen,4 and T. Derlin2; 1Hannover Medical School, Department of Radiation Oncology, Hannover, Germany, 2Hannover Medical School, Department of Nuclear Medicine, Hannover, Germany, 3Technical University of Munich, Pharmaceutical Radiochemistry, Munich, Germany, 4Hannover Medical School, Department of Radiation Oncology, Hannover, Germany Purpose/Objective(s): Assessment of early efficacy 68 eof PSMA-PET / CT-based radiation therapy for locally recurrent or oligometastatic prostate cancer after primary therapy. Materials/Methods: Nineteen patients (18/19 (94.7%) with a high-risk carcinoma) presented with biochemical PSA failure after definitive therapy and received additionally to the conventional staging a 68Ga-PSMA PET / CT scan. PET-positive lesions outside the prostate bed received a normofractionated 3D conformal radiation therapy with a dose of 50-54 Gy. PET-positive lesions in the prostate bed were treated with a dose of 66 Gy in VMAT technique. All patients had regular follow-up visits on a three months basis. Any increase in PSA levels above the baseline level three months after radiation therapy triggered a new PSMA-PET / CT scan. Androgen deprivation therapy (ADT) was continued during radiation therapy, but was not initiated in patients who had no ADT. Systemic therapy was only initiated in case of biochemical failure after radiation therapy in patients with an ADT. All cases were approved by local urooncological board. Results: All patients (n Z 19), 100%) presented with a pathological tracer uptake. The PSMA-PET / CT showed that 15.8% (n Z 3) had local recurrence in the prostate bed, 47.6% (n Z 9) had isolated pelvic lymph node metastasis and 26.3% (n Z 5) had isolated bone metastases. One patient (5.3%) had pelvic lymph node metastases and one bone metastases. The median follow-up was 5.8 months (range, 3.0-12.9). The median PSA level before irradiation was 1.3 ng / ml (range, 0.52 - 32.01) and decreased statistically significant to 0.31 (range, <0.07 to 4.23; P <0.001) at the last follow-up visit. One patient (5.3%) with a PSA increase above the baseline level 12.7 months after irradiation showed new PSMA PET positive paraaortic lymph nodes outside the former radiation field. He declined an ADT and he received radiation therapy of the PET positive paraaortic lymph nodes. At the median follow-up of 5.7 months a biochemical progression-free survival (BPFS) and distant disease-free survival (DDFS) of 100% was observed. Furthermore no grade III acute toxicities according to CTCAE or late toxicity grade II according to the LENT-SOMA criteria were observed. A total of 10.6% (n Z 2) reported about a persistent diarrhea grade I without impairing fecal continence. Conclusion: These early results showed that a 68Ga-PSMA PET / CTbased radiation therapy yields effective local control, significantly improved the PSA kinetics, delayed the initiation of chemotherapy in patients with ADT or can defer ADT in ADT-naive patients. Moreover, this treatment is not associated with clinically relevant late side effects. Author Disclosure: C. Henkenberens: None. F. Bengel: None. H. Wester: None. H. Christiansen: None. T. Derlin: None.