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957 poster Salvage intensity-modulated radiotherapy (IMRT) for biochemical relapse of prostate cancer after radical prostatectomy: initial clinical results
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Figure 1: Schematic presentation of the distinct categories of sigmoid colon and its relation to the planning target volume (PTV). The PTV is presented in pink, the rectum in brown and the sigmoid colon in green.
Results: The PTV was found to overlap with S in 60% and with SB in 19% of the cases (categry A). In these patients, mean maximal dose to S was 76.2 Gy (5th-95 th percentile: 70.0 - 80.7 Gy). T his was significantly higher than in all other categories. Mean maximal dose to SB was 74.9 Gy (5th-95 th percentile: 68.0 80.0 Gy). There was no correlation between bladder volume and position of the SB. Conclusion: When we systematically investigated the anatomical position of sigmoid colon and small bowel in patients accepted for prostate irradiation, parts of both organs were often observed in close vicinity with the PTV. Apart from the rectum, these organs may be dose limiting in prostate radiotherapy. 956 poster
Comparison of low risk prostate cancer patients positioned with and without implanted gold markers and online portal imaging based on magnetic resonance spectroscopic imaging
B. Pickett ~, J. Pouliot ~, J. Kurhanewicz 2, K. Shinohara 3, M. ~ . Roach ~'3 ~University of California, San Francisco, Radiation Oncology, San Francisco, U.S.A. 2University of California, San Francisco, Radiology, San Francisco, U.S.A. 3University of California, San Francisco, Urology, San Francisco, U.S.A. Objective: Recent studies suggest that treatment of low risk prostate cancer with external beam radiation therapy (EBRT) to > 72 Gy yields a mean time to resolution of disease (TRD) of 32.2 months based on magnetic resonance spectroscopic imaging (MRSI) (Pickett, IJROBP, 2003). The objective of this study was to compare the TRD when implanted gold markers were used to reposition the prostate with online portal imaging defining a more accurate focally defined treatment aperature. Methodology: Twenty patients with (Pw) and 20 patients without (Po) implanted gold markers had MRSI examinations prior to and/or at various times following therapy. All patients were considered low risk, with Gleason Scores = 6, PSA < 10, and stage < T2. The patients were grouped by treatment type (Pw and Po) with a median prescribed dose of 72 Gy (range 68-75.6). The spectra from all usable voxels within the prostate were examined for detectable levels of metabolic signal and the percent of voxels in each category were tabulated as atrophic, cancerous or healthy. The TRD and the time to PSA nadir (nPSA) were tabulated. The threedimensional shifts needed to align the gold markers to the digitally reconstructed radiograph and the percent and location of the pre-treatment MRSI defined cancer was also documented. Results: The mean TRD was 21.2 and 32.2 months with a mean time to nPSA of 34.0 and 42.2 months for Pw and Po patients, respectively. Over time our results suggest a gradual increase in atrophy, and a consistent decline in cancerous metabolism. Ninety percent of the Po patients with EBRT obtained a (-) post treatment MRSI (< 6 mm contiguous residual cancer), while 10% had a (+) MRSI (> 6 mm contiguous residual cancer). All 20 Pw patients had (-) MRSI studies with 94% achieving complete metabolic atrophy (CMA). Patients with pretreatment cancer defined in
Posters
the posterior aspect of the prostate achieved resolution of disease -10 months later when gold marker seeds were not implanted.
Conclusion: This study implies that a more focally defined EBRT treatment identified by implanted gold markers and verified by online portal imaging can be more effective at targeting the prostate gland and seems to destroy prostate metabolism faster in patients with implanted gold markers. 957 poster
Salvage intensity-modulated radiotherapy (IMRT) for biochemical relapse of prostate cancer after radical prostatectomy: initial clinical results
S. Meersschout 1, L. Vakaet 1, G. Villeirs 2, W. De Neve ~, W. Oosterlinck 3, A. Verbaeys 3, G. De Meerleer ~ ~Gent University Hospital, Radiotherapy, Gent, Belgium 2Gent University Hospital, Radiology, Gent, Belgium 3Gent University Hospital, Urology, Gent, Belgium Purpose: To evaluate prospectively the biochemical tumor control and toxicity in patients treated with salvage IMRT (SIMRT) for biochemical relapse after radical prostatectomy for prostate cancer. Materials and methods: This study contains 32 patients. All patients had been free from lymfatic or hematogeneous metastasis. In 14 patients the biochemical relapse was visible on MRI and/or palpable on digital rectal examination. All patients were treated with S-IMRT using 3 or 7 coplanar beams and anatomy-based beam segments [1]. The clinical target CTV was the bed of the prostate and seminal vesicles. The PTV was created using a margin of 7 mm around the CTV. Details on the use of biophysical objective function and leaf position optimisation were described previously [2,3]. High risk patients (n=19) were treated with androgen deprivation (AD)for a period of 6 months. All patients who entered our S-IMRT protocol were prospectively evaluated using the RTOG-toxicity scales, supplemented with standardized in house developed symptom scales [4]. "Biochemical no evidence of disease" (bNED) was defined following the ASTRO guidelines [5]. Patients were evaluated pre-treatment, during (weekly basis) and at the end of SIMRT and at 1 and 3 months, 3-monthly during the first year and 6-monthly thereafter. Results: Mean age was 65 years (52 - 81 years). Median follow-up was 12 months (1 - 60 months). Mean and median times between radical prostatectomy and start of radiation treatment were 31 and 20 months respectively (2 - 149 months). Median pre-RT PSA was 1.48 ng/mL (0.13-19.6 ng/mL). The actuarial bNED at 36 months after treatment was 88 % (SE 9.6 %). The actuarial risk of any grade 2 or more toxicity was respectively for any GI toxicity score 22 % (SE 9.9 %) and for any GU toxicity score 14% (SE 7.9 %). Conclusion: S-IMRT with or without AD is a safe and effective treatment for isolated local recurrence after radical prostatectomy. Further follow-up is needed and will be performed meticulously. 958 poster
Chronic toxicity rates in two dose-escalation trials for intermediate/advanced prostate cancer. External-beam radiation therapy (EBRT) with high-dose rate brachytherapy (HDR-BT) boost vs adaptive radiation therapy (ART) delivered with 3D conformal or intensitymodulated techniques
M. Ghilezan 1, D. Yan 2, C. Vargas 1, D. Lockman 2, D.
Figure 1: Schematic presentation of the distinct categories of sigmoid colon and its relation to the planning target volume (PTV). The PTV is presented in pink, the rectum in brown and the sigmoid colon in green.
Results: The PTV was found to overlap with S in 60% and with SB in 19% of the cases (categry A). In these patients, mean maximal dose to S was 76.2 Gy (5th-95 th percentile: 70.0 - 80.7 Gy). T his was significantly higher than in all other categories. Mean maximal dose to SB was 74.9 Gy (5th-95 th percentile: 68.0 80.0 Gy). There was no correlation between bladder volume and position of the SB. Conclusion: When we systematically investigated the anatomical position of sigmoid colon and small bowel in patients accepted for prostate irradiation, parts of both organs were often observed in close vicinity with the PTV. Apart from the rectum, these organs may be dose limiting in prostate radiotherapy. 956 poster
Comparison of low risk prostate cancer patients positioned with and without implanted gold markers and online portal imaging based on magnetic resonance spectroscopic imaging
B. Pickett ~, J. Pouliot ~, J. Kurhanewicz 2, K. Shinohara 3, M. ~ . Roach ~'3 ~University of California, San Francisco, Radiation Oncology, San Francisco, U.S.A. 2University of California, San Francisco, Radiology, San Francisco, U.S.A. 3University of California, San Francisco, Urology, San Francisco, U.S.A. Objective: Recent studies suggest that treatment of low risk prostate cancer with external beam radiation therapy (EBRT) to > 72 Gy yields a mean time to resolution of disease (TRD) of 32.2 months based on magnetic resonance spectroscopic imaging (MRSI) (Pickett, IJROBP, 2003). The objective of this study was to compare the TRD when implanted gold markers were used to reposition the prostate with online portal imaging defining a more accurate focally defined treatment aperature. Methodology: Twenty patients with (Pw) and 20 patients without (Po) implanted gold markers had MRSI examinations prior to and/or at various times following therapy. All patients were considered low risk, with Gleason Scores = 6, PSA < 10, and stage < T2. The patients were grouped by treatment type (Pw and Po) with a median prescribed dose of 72 Gy (range 68-75.6). The spectra from all usable voxels within the prostate were examined for detectable levels of metabolic signal and the percent of voxels in each category were tabulated as atrophic, cancerous or healthy. The TRD and the time to PSA nadir (nPSA) were tabulated. The threedimensional shifts needed to align the gold markers to the digitally reconstructed radiograph and the percent and location of the pre-treatment MRSI defined cancer was also documented. Results: The mean TRD was 21.2 and 32.2 months with a mean time to nPSA of 34.0 and 42.2 months for Pw and Po patients, respectively. Over time our results suggest a gradual increase in atrophy, and a consistent decline in cancerous metabolism. Ninety percent of the Po patients with EBRT obtained a (-) post treatment MRSI (< 6 mm contiguous residual cancer), while 10% had a (+) MRSI (> 6 mm contiguous residual cancer). All 20 Pw patients had (-) MRSI studies with 94% achieving complete metabolic atrophy (CMA). Patients with pretreatment cancer defined in
Posters
the posterior aspect of the prostate achieved resolution of disease -10 months later when gold marker seeds were not implanted.
Conclusion: This study implies that a more focally defined EBRT treatment identified by implanted gold markers and verified by online portal imaging can be more effective at targeting the prostate gland and seems to destroy prostate metabolism faster in patients with implanted gold markers. 957 poster
Salvage intensity-modulated radiotherapy (IMRT) for biochemical relapse of prostate cancer after radical prostatectomy: initial clinical results
S. Meersschout 1, L. Vakaet 1, G. Villeirs 2, W. De Neve ~, W. Oosterlinck 3, A. Verbaeys 3, G. De Meerleer ~ ~Gent University Hospital, Radiotherapy, Gent, Belgium 2Gent University Hospital, Radiology, Gent, Belgium 3Gent University Hospital, Urology, Gent, Belgium Purpose: To evaluate prospectively the biochemical tumor control and toxicity in patients treated with salvage IMRT (SIMRT) for biochemical relapse after radical prostatectomy for prostate cancer. Materials and methods: This study contains 32 patients. All patients had been free from lymfatic or hematogeneous metastasis. In 14 patients the biochemical relapse was visible on MRI and/or palpable on digital rectal examination. All patients were treated with S-IMRT using 3 or 7 coplanar beams and anatomy-based beam segments [1]. The clinical target CTV was the bed of the prostate and seminal vesicles. The PTV was created using a margin of 7 mm around the CTV. Details on the use of biophysical objective function and leaf position optimisation were described previously [2,3]. High risk patients (n=19) were treated with androgen deprivation (AD)for a period of 6 months. All patients who entered our S-IMRT protocol were prospectively evaluated using the RTOG-toxicity scales, supplemented with standardized in house developed symptom scales [4]. "Biochemical no evidence of disease" (bNED) was defined following the ASTRO guidelines [5]. Patients were evaluated pre-treatment, during (weekly basis) and at the end of SIMRT and at 1 and 3 months, 3-monthly during the first year and 6-monthly thereafter. Results: Mean age was 65 years (52 - 81 years). Median follow-up was 12 months (1 - 60 months). Mean and median times between radical prostatectomy and start of radiation treatment were 31 and 20 months respectively (2 - 149 months). Median pre-RT PSA was 1.48 ng/mL (0.13-19.6 ng/mL). The actuarial bNED at 36 months after treatment was 88 % (SE 9.6 %). The actuarial risk of any grade 2 or more toxicity was respectively for any GI toxicity score 22 % (SE 9.9 %) and for any GU toxicity score 14% (SE 7.9 %). Conclusion: S-IMRT with or without AD is a safe and effective treatment for isolated local recurrence after radical prostatectomy. Further follow-up is needed and will be performed meticulously. 958 poster
Chronic toxicity rates in two dose-escalation trials for intermediate/advanced prostate cancer. External-beam radiation therapy (EBRT) with high-dose rate brachytherapy (HDR-BT) boost vs adaptive radiation therapy (ART) delivered with 3D conformal or intensitymodulated techniques
M. Ghilezan 1, D. Yan 2, C. Vargas 1, D. Lockman 2, D.