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716 poster INTERSTITIAL BRACHYTHERAPY (IB) FOR LOCALIZED PROSTATE CANCER (LPC): THE TRENTO EXPERIENCE.
B RACHYTHERAPY: P ROSTATE C ANCER
715 poster INTEROBSERVER VARIATION IN MRI AND CT BASED CONTOURING FOR PROSTATE CANCER B. Segedin1 , J. But Hadzic1 , P. Rogelj2 , M. Sesek1 , H. B. Zobec Logar1 , B. Kragelj1 , P. Petric1 1 I NSTITUTE OF O NCOLOGY L JUBLJANA, Ljubljana, Slovenia 2 FACULTY OF M ATHEMATICS , N ATURAL S CIENCES AND I NFORMATION T ECHNOLOGIES, Koper, Slovenia Purpose: Capability for conformal dose escalation, afforded by brachytherapy (BT), exceeds any other radiotherapy modality. Even minimal contouring variation may result in significant dose delivery uncertainties, undermining overall treatment efficacy. We aimed to quantify feasibility of delineation and degree of interobserver variation in MRI and CT based contouring for prostate BT. Materials: At the Institute of Oncology Ljubljana, intermediate and high risk prostate cancer patients are treated with pelvic external beam radiotherapy, followed by MRI-based PDR BT boost. After ultrasound-guided needle insertion, pelvic MRI is obtained for planning. Three fractions of 6 Gy (10 h interfraction interval) are applied to gland periphery. Prior to 3rd fraction, CT is performed to quantify implant displacement. In this study, prostate was outlined by 4 radiation oncologists in 5 consecutive patients (test contours) on MRI and CT. Ability to discriminate gland apex, base and lateral borders on both modalities was scored by each observer, utilizing a 3-tiered scale (1-poor, 2-moderate, 3-excellent). Test contours were compared to reference delineations, representing a consensus of two senior radiation oncologists. Dedicated software, developed ar our department, was used to perform quantitative volumetric and topographic analysis of contouring variation for both modalities. Results: Mean ability to discriminate apex, base and lateral prostate borders was higher on MRI (2.5, 2.5 and 2.8, respectively), when compared with CT (1.4, 1.6 and 2.0, respectively). Sizes of contoured volumes were 41 ± 15 and 45 ± 14 cm3 on MRI and CT, respectively. Ratio between common and encompassing volume of reference and test contours was higher for MRI than CT (0.83 ± 0.04 vs. 0.69 ± 0.05 mm). Radial inter-contour distances were smaller on MRI than CT (1.5 ± 0.4 vs. 3.5 ± 0.7 mm). Maps of variation distribution were created. Variations were most pronounced in apical region for both modalities. Mean cranio-caudal distance between reference and test contours was smaller on MRI (base: 0.8 ± 1.6 mm; apex: 1.9 ± 2.7 mm) when compared with CT (base: 2.9 ± 2.1 mm; apex: 3.4 ± 2.6 mm). Conclusions: MRI enables superior definition of outer prostate boundaries when compared with CT. Using MRI, contouring variation and resulting dose delivery uncertainties in temporary prostate BT can be minimized. 716 poster INTERSTITIAL BRACHYTHERAPY (IB) FOR LOCALIZED PROSTATE CANCER (LPC): THE TRENTO EXPERIENCE. G. Fellin1 , S. Mussari1 , C. Divan2 , F. Coccarelli2 , O. Caffo3 , F. Ziglio4 1 O SPEDALE S ANTA C HIARA, Radiotherapy, Trento, Italy 2 O SPEDALE S ANTA C HIARA, Urology, Trento, Italy 3 O SPEDALE S ANTA C HIARA, Oncology, Trento, Italy 4 O SPEDALE S ANTA C HIARA, Trento, Italy Purpose: IB is a therapeutic option for radical treatment of LPC and this therapy has been offered to selected patients (pts) in our Hospital from 2000. The IB management has been performed by a dedicated Brachytherapy Pool (BP) involving the departments of Radiotherapy, Urology, Medical Oncology, and Health physics. The present report is aimed to retrospectively report the Trento experience. Materials: From May 2000 to December 2008, we treated with IB a consecutive series of 409 pts with LCP. The IB consisted of I125 permanent implant and was performed as exclusive treatment in 380 pts (with a delivered dose of 145 Gy) and as a boost treatment (with a delivered dose of 100 Gy) in association with 45-50.4 Gy external beam radiotherapy in 29 cases. A short-term pre-IB hormonal therapy was performed in 153 pts. The median age was 66 yrs (range 49-78); the NCCN risk class was low, medium and high in 68%, 30% and 2% of the cases respectively. CT-based dosimetry at 4 weeks after implant was used for post-planning evaluation. D90 and V100 were recorded for each patient, along with other dosimetric parameters. The biochemical relapse (BR) was defined according to the Phoenix ASTRO Consensus Conference recommendations. Side effects and quality of life (QL) were recorded. Results: The prescribed D90≥100% and V100 ≥90% dose was achieved by 83% of the pts. A RTOG grade ≥2 urinary toxicity was observed in 15% of the cases with 2% requiring temporary use of catheter due to acute urinary retention. Twelve pts (3%) showed a G1 rectal toxicity. Late grade ≥1 urinary toxicity was observed in 10.5% of the pts with 2.5% requiring a TURP. After a median follow-up of 55 months, the relapse rate was 11% with 8 pts (2%) developing a clinical relapse and 36 (9%) showing only a biochemical relapse. The 5- and 10-yrs relapse free survival (RFS) was 92% and 79%, respectively. At this time, 30 pts dead (27 relapse free), with a 5- and 10-yrs overall survival of 93% and 85%, respectively. Low-risk pts had better RFS compared to intermediate-risk (5-y: 95% vs 88%; 10-y: 80% vs 73%; p: NS). Similarly,
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pts with better dosimetric parameters (V100≥90% and D90≥100%) had better PFS compared to the others (5y: 95 vs 80%; p<0.05). QL outcomes of pts treated until 2005 has been previously published (IJROBP 66: 3137, 2006). A new prospective QL evaluation started from 2005 and is ongoing. Conclusions: Our data reproduce the outcomes of larger published series. In this view, IB may be considered as an effective treatment not only in low- but also in intermediate risk LPC. Dosimetric quality parameters (D90 and V100) significantly influence biochemical outcome. The multidisciplinary management of IB represents an added value in enhancing pts selection and IB quality. 717 poster INTERSTITIAL HIGH DOSE RATE (HDR) BRACHYTHERAPY AS MONOTHERAPY FOR EARLY STAGE PROSTATE CANCER : MEDIAN 8 YEAR RESULTS IN 319 PATIENTS R. Mark1 , R. Akins2 , M. White3 , M. Nair2 1 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department for Radiation Oncology and Experimental Cancer Research, Lubbock, Texas, USA 2 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department of Radiation Oncology, Lubbock, USA 3 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department for Radiation Oncology - section Quantitative Magnetic Resonance Imaging, Lubbock, Texas, USA Purpose: Transrectal Ultrasound (TRUS) guided interstitial implant for prostate cancer using Low Dose Rate (LDR) and High Dose Rate (HDR) technique has been reported with results comparing favorably to surgery and External Beam Radiation Therapy (EBRT). Often, HDR and LDR interstitial implant is combined with EBRT. There is little published data on HDR alone. We report our results with HDR alone. Materials: Between 1997 and 2010, 319 patients with T1 and T2 localized prostate underwent TRUS guided interstitial implant, under spinal anesthetic or local anesthetic. There were no Gleason Score or PSA exclusions. No patient received EBRT or Hormonal Blockade. Median Gleason Score was 7 (range : 4 to 10). Median PSA was 9.3 (2.7 to 39.8). Treatment volumes ranged from 32 cm3 to 196 cm3 . Treatment volume included the prostate and seminal vesicles in all cases. Radiation Treatment planning was performed using CT Scanning and the Nucletron Plato Treatment Planning System. Our IRB protocol for HDR alone, has called for two HDR Implants, spaced 4 weeks apart. The treatment volume received 2,250 cGy in 3 fractions prescribed to the 100% Isodose line, given over 24 hours. A 2nd implant was performed 4 weeks later, delivering a further 2,250 cGy in 3 fractions, bringing the final dose to the prostate to 4,500 cGy in 6 fractions. Urethral dose points (12-16) were followed, and limited to < 105% of the prescription dose. Results: With a median follow-up of 102 months (range : 6 months to 174 months), PSA disease free survival was 88.7% (283/319). Actuarial 8 year PSA disease free survival was 86%. The actuarial 8 year PSA DFSs by risk group, were 94% for low risk, 86% for intermediate risk, and 65% for high risk. The procedure was well tolerated, with all patients having completed the procedure. Acute and chronic complications were uncommon. Acute urinary retention occurred in 5.0% (16/319) of the patients, requiring temporary insertion of an indwelling foley catheter. Urethral stricture requiring dilatation has developed in 5.6% (18/319) of patients. Urinary stress incontinence has occurred in 2.8% (9/319). RTOG late bladder toxicities were : 0% Grade 4, 0% Grade 3, and 2.8% (9/319) Grade 2. RTOG late rectal toxicities were : 0.6% (2/319) Grade 4, 0% Grade 3, 1.0% (3/319) Grade 2, and 1.3% (4/319) Grade 1. Conclusions: Eight year results with HDR implant alone compare favorably to EBRT, LDR +/- EBRT, and HDR + EBRT, both with regard to PSA disease free survival, and complications. HDR offers other advantages over LDR, such as no radiation exposure to hospital personnel, no seed migration, greater dose flexibility and precision of radiation dose delivery. Larger volumes can be treated with HDR. By omitting EBRT, bladder and rectal complications appear to be significantly reduced. 718 poster INTERSTITIAL HIGH DOSE RATE (HDR) BRACHYTHERAPY UNDER LOCAL ANESTHESIA FOR EARLY STAGE PROSTATE CANCER : A REPORT OF 546 CASES R. Hargrove1 , R. Mark1 , R. Akins2 , M. Nair3 1 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department of Radiation Oncology, Section of Radiobiology, Lubbock, USA 2 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Departments of Radiation Oncology, and Imaging Research, Lubbock, Texas, USA 3 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department of Radiation Oncology, Lubbock, Texas, USA
Purpose: Transrectal Ultrasound (TRUS) guided interstitial implant for prostate cancer using Low Dose Rate (LDR) and High Dose Rate (HDR) techniques has been reported with results comparing very favorably to ex-
715 poster INTEROBSERVER VARIATION IN MRI AND CT BASED CONTOURING FOR PROSTATE CANCER B. Segedin1 , J. But Hadzic1 , P. Rogelj2 , M. Sesek1 , H. B. Zobec Logar1 , B. Kragelj1 , P. Petric1 1 I NSTITUTE OF O NCOLOGY L JUBLJANA, Ljubljana, Slovenia 2 FACULTY OF M ATHEMATICS , N ATURAL S CIENCES AND I NFORMATION T ECHNOLOGIES, Koper, Slovenia Purpose: Capability for conformal dose escalation, afforded by brachytherapy (BT), exceeds any other radiotherapy modality. Even minimal contouring variation may result in significant dose delivery uncertainties, undermining overall treatment efficacy. We aimed to quantify feasibility of delineation and degree of interobserver variation in MRI and CT based contouring for prostate BT. Materials: At the Institute of Oncology Ljubljana, intermediate and high risk prostate cancer patients are treated with pelvic external beam radiotherapy, followed by MRI-based PDR BT boost. After ultrasound-guided needle insertion, pelvic MRI is obtained for planning. Three fractions of 6 Gy (10 h interfraction interval) are applied to gland periphery. Prior to 3rd fraction, CT is performed to quantify implant displacement. In this study, prostate was outlined by 4 radiation oncologists in 5 consecutive patients (test contours) on MRI and CT. Ability to discriminate gland apex, base and lateral borders on both modalities was scored by each observer, utilizing a 3-tiered scale (1-poor, 2-moderate, 3-excellent). Test contours were compared to reference delineations, representing a consensus of two senior radiation oncologists. Dedicated software, developed ar our department, was used to perform quantitative volumetric and topographic analysis of contouring variation for both modalities. Results: Mean ability to discriminate apex, base and lateral prostate borders was higher on MRI (2.5, 2.5 and 2.8, respectively), when compared with CT (1.4, 1.6 and 2.0, respectively). Sizes of contoured volumes were 41 ± 15 and 45 ± 14 cm3 on MRI and CT, respectively. Ratio between common and encompassing volume of reference and test contours was higher for MRI than CT (0.83 ± 0.04 vs. 0.69 ± 0.05 mm). Radial inter-contour distances were smaller on MRI than CT (1.5 ± 0.4 vs. 3.5 ± 0.7 mm). Maps of variation distribution were created. Variations were most pronounced in apical region for both modalities. Mean cranio-caudal distance between reference and test contours was smaller on MRI (base: 0.8 ± 1.6 mm; apex: 1.9 ± 2.7 mm) when compared with CT (base: 2.9 ± 2.1 mm; apex: 3.4 ± 2.6 mm). Conclusions: MRI enables superior definition of outer prostate boundaries when compared with CT. Using MRI, contouring variation and resulting dose delivery uncertainties in temporary prostate BT can be minimized. 716 poster INTERSTITIAL BRACHYTHERAPY (IB) FOR LOCALIZED PROSTATE CANCER (LPC): THE TRENTO EXPERIENCE. G. Fellin1 , S. Mussari1 , C. Divan2 , F. Coccarelli2 , O. Caffo3 , F. Ziglio4 1 O SPEDALE S ANTA C HIARA, Radiotherapy, Trento, Italy 2 O SPEDALE S ANTA C HIARA, Urology, Trento, Italy 3 O SPEDALE S ANTA C HIARA, Oncology, Trento, Italy 4 O SPEDALE S ANTA C HIARA, Trento, Italy Purpose: IB is a therapeutic option for radical treatment of LPC and this therapy has been offered to selected patients (pts) in our Hospital from 2000. The IB management has been performed by a dedicated Brachytherapy Pool (BP) involving the departments of Radiotherapy, Urology, Medical Oncology, and Health physics. The present report is aimed to retrospectively report the Trento experience. Materials: From May 2000 to December 2008, we treated with IB a consecutive series of 409 pts with LCP. The IB consisted of I125 permanent implant and was performed as exclusive treatment in 380 pts (with a delivered dose of 145 Gy) and as a boost treatment (with a delivered dose of 100 Gy) in association with 45-50.4 Gy external beam radiotherapy in 29 cases. A short-term pre-IB hormonal therapy was performed in 153 pts. The median age was 66 yrs (range 49-78); the NCCN risk class was low, medium and high in 68%, 30% and 2% of the cases respectively. CT-based dosimetry at 4 weeks after implant was used for post-planning evaluation. D90 and V100 were recorded for each patient, along with other dosimetric parameters. The biochemical relapse (BR) was defined according to the Phoenix ASTRO Consensus Conference recommendations. Side effects and quality of life (QL) were recorded. Results: The prescribed D90≥100% and V100 ≥90% dose was achieved by 83% of the pts. A RTOG grade ≥2 urinary toxicity was observed in 15% of the cases with 2% requiring temporary use of catheter due to acute urinary retention. Twelve pts (3%) showed a G1 rectal toxicity. Late grade ≥1 urinary toxicity was observed in 10.5% of the pts with 2.5% requiring a TURP. After a median follow-up of 55 months, the relapse rate was 11% with 8 pts (2%) developing a clinical relapse and 36 (9%) showing only a biochemical relapse. The 5- and 10-yrs relapse free survival (RFS) was 92% and 79%, respectively. At this time, 30 pts dead (27 relapse free), with a 5- and 10-yrs overall survival of 93% and 85%, respectively. Low-risk pts had better RFS compared to intermediate-risk (5-y: 95% vs 88%; 10-y: 80% vs 73%; p: NS). Similarly,
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pts with better dosimetric parameters (V100≥90% and D90≥100%) had better PFS compared to the others (5y: 95 vs 80%; p<0.05). QL outcomes of pts treated until 2005 has been previously published (IJROBP 66: 3137, 2006). A new prospective QL evaluation started from 2005 and is ongoing. Conclusions: Our data reproduce the outcomes of larger published series. In this view, IB may be considered as an effective treatment not only in low- but also in intermediate risk LPC. Dosimetric quality parameters (D90 and V100) significantly influence biochemical outcome. The multidisciplinary management of IB represents an added value in enhancing pts selection and IB quality. 717 poster INTERSTITIAL HIGH DOSE RATE (HDR) BRACHYTHERAPY AS MONOTHERAPY FOR EARLY STAGE PROSTATE CANCER : MEDIAN 8 YEAR RESULTS IN 319 PATIENTS R. Mark1 , R. Akins2 , M. White3 , M. Nair2 1 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department for Radiation Oncology and Experimental Cancer Research, Lubbock, Texas, USA 2 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department of Radiation Oncology, Lubbock, USA 3 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department for Radiation Oncology - section Quantitative Magnetic Resonance Imaging, Lubbock, Texas, USA Purpose: Transrectal Ultrasound (TRUS) guided interstitial implant for prostate cancer using Low Dose Rate (LDR) and High Dose Rate (HDR) technique has been reported with results comparing favorably to surgery and External Beam Radiation Therapy (EBRT). Often, HDR and LDR interstitial implant is combined with EBRT. There is little published data on HDR alone. We report our results with HDR alone. Materials: Between 1997 and 2010, 319 patients with T1 and T2 localized prostate underwent TRUS guided interstitial implant, under spinal anesthetic or local anesthetic. There were no Gleason Score or PSA exclusions. No patient received EBRT or Hormonal Blockade. Median Gleason Score was 7 (range : 4 to 10). Median PSA was 9.3 (2.7 to 39.8). Treatment volumes ranged from 32 cm3 to 196 cm3 . Treatment volume included the prostate and seminal vesicles in all cases. Radiation Treatment planning was performed using CT Scanning and the Nucletron Plato Treatment Planning System. Our IRB protocol for HDR alone, has called for two HDR Implants, spaced 4 weeks apart. The treatment volume received 2,250 cGy in 3 fractions prescribed to the 100% Isodose line, given over 24 hours. A 2nd implant was performed 4 weeks later, delivering a further 2,250 cGy in 3 fractions, bringing the final dose to the prostate to 4,500 cGy in 6 fractions. Urethral dose points (12-16) were followed, and limited to < 105% of the prescription dose. Results: With a median follow-up of 102 months (range : 6 months to 174 months), PSA disease free survival was 88.7% (283/319). Actuarial 8 year PSA disease free survival was 86%. The actuarial 8 year PSA DFSs by risk group, were 94% for low risk, 86% for intermediate risk, and 65% for high risk. The procedure was well tolerated, with all patients having completed the procedure. Acute and chronic complications were uncommon. Acute urinary retention occurred in 5.0% (16/319) of the patients, requiring temporary insertion of an indwelling foley catheter. Urethral stricture requiring dilatation has developed in 5.6% (18/319) of patients. Urinary stress incontinence has occurred in 2.8% (9/319). RTOG late bladder toxicities were : 0% Grade 4, 0% Grade 3, and 2.8% (9/319) Grade 2. RTOG late rectal toxicities were : 0.6% (2/319) Grade 4, 0% Grade 3, 1.0% (3/319) Grade 2, and 1.3% (4/319) Grade 1. Conclusions: Eight year results with HDR implant alone compare favorably to EBRT, LDR +/- EBRT, and HDR + EBRT, both with regard to PSA disease free survival, and complications. HDR offers other advantages over LDR, such as no radiation exposure to hospital personnel, no seed migration, greater dose flexibility and precision of radiation dose delivery. Larger volumes can be treated with HDR. By omitting EBRT, bladder and rectal complications appear to be significantly reduced. 718 poster INTERSTITIAL HIGH DOSE RATE (HDR) BRACHYTHERAPY UNDER LOCAL ANESTHESIA FOR EARLY STAGE PROSTATE CANCER : A REPORT OF 546 CASES R. Hargrove1 , R. Mark1 , R. Akins2 , M. Nair3 1 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department of Radiation Oncology, Section of Radiobiology, Lubbock, USA 2 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Departments of Radiation Oncology, and Imaging Research, Lubbock, Texas, USA 3 J OE A RRINGTON C ANCER AND R ESEARCH C ENTER, Department of Radiation Oncology, Lubbock, Texas, USA
Purpose: Transrectal Ultrasound (TRUS) guided interstitial implant for prostate cancer using Low Dose Rate (LDR) and High Dose Rate (HDR) techniques has been reported with results comparing very favorably to ex-