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Interstitial High-Dose-Rate Brachytherapy Under Local Anesthesia for Early Stage Prostate Cancer: A Report of 546 Cases
Abstracts / Brachytherapy 10 (2011) S14eS101 PO28 High-Dose-Rate Brachytherapy Combined With External Beam Radiotherapy for Localized Prostate Cancer: Clinical Predictive Factor for Biochemical Relapse-Free Survival Shinji Kariya, MD, PhD1, Ichiro Yamasaki, MD, PhD2, Kenji Tamura, MD, PhD2, Taro Shuin, MD, PhD2, Akihito Nishioka, MD, PhD1, Yasuhiro Ogawa, MD, PhD1. 1Diagnostic Radiology & Radiation Oncology, Kochi Medical School, Nankoku, Kochi, Japan; 2Urology, Kochi Medical School, Nankoku, Kochi, Japan. Purpose: The aim of this study is to determine what kind of clinical factors were predictive for biochemical relapse-free survival (bRFS) of prostate cancer (CaP) patients treated with high-dose-rate brachytherapy (HDRBT) combined with external beam radiotherapy (EBRT). Materials and Methods: Between July 1999 and September 2007, 15, 51 and 41 patients considered as low-risk group (stage ! or 5 T2a, PSA ! or 5 10 ng/mL, and Gleason score (GS) ! or 5 6), intermediate-risk group (stage 5 T2b, 10 ! PSA ! or 5 20 ng/mL, or GS 5 7), and high-risk group (stage O or 5 T2c, PSA O20 ng/mL, or Gleason score O or 5 8), respectively, were treated with HDR-BT followed by EBRT at Kochi Medical School Hospital in Japan. Patient age ranged from 55 to 81 years (median 71). Forty-two patients had received neoadjuvant hormonal therapy, which was stopped at the beginning of radiotherapy in all cases. Patients were treated with EBRT to 39e45 Gy in 13e25 fractions, and HDR-BT to 18 Gy in 2e3 fractions for prostate. Adjuvant hormonal therapy was not performed until biochemical failure or clinical recurrence became apparent. PSA failure was defined as the Phoenix definition of nadir þ 2ng/mL. The bRFS rates were estimated using the Kaplan-Meier method. The median followup was 60 months (range, 36 e 134 months). Cox proportional hazards regression analysis was used for univariate and multivariate analyses examining these factors in relation to bRFS: clinical T stage, initial PSA level, GS and use of neoadjuvant hormonal therapy. A two-side p value of !0.05 was considered statistically-significant. Results: The 5-year bRFS rate in low-, intermediate- and high-risk group were 100%, 97.9%, and 83.7%, respectively. The 5-year bRFS rate in high-risk group was statistically inferior to that in intermediate-risk group (p 5 0.0206). On univariate and multivariate analyses, clinical T state remained an independent predictor of bRES. None of initial PSA level, GS, or use of neoadjuvant hormonal therapy was not predictive factor for bRFS of CaP patient with HDR-BT combined with EBRT. Conclusions: Clinical T3 CaP carried a worse bRFS than clinical T1-2 Cap. For the improvement of bRFS in T3Cap, adjuvant hormonal therapy may be needed for HDR-BT combined with EBRT.
PO29 Inferring Postimplant Dosimetry and Determining Low Radiation Dose Volumes Using Images Obtained at the Time of Recurrence After Permanent Prostate Implant Brachytherapy: A Pragmatic Study Devan Krishnamurthy, PhD, Gilles Crehange, MD, J. Adam M. Cunha, PhD, Dilini Pinnaduwage, PhD, Barby Pickett, PhD, I-Chow Hsu, MD, Alexander Gottschalk, MD, Mack Roach III, MD, Jean Pouliot, PhD. Radiation Oncology, University of California San Francisco, San Francisco, CA. Purpose: Some patients (Pts) with a clinically localized prostate cancer who underwent prostate permenant-seed implant (PPI) have a biochemical failure. This recurrence could be correlated with low radiation dose volumes on the preoperative or postoperative PPI dosimetric plans. Unfortunately, 30-day post implant dosimetry information is not always available at time of recurrence. The purpose of this work is to establish a method for evaluating dosimetry at the time of implant using (1) an pelvic MR image at time of recurrence and (2) the recorded prostate volume at the time of implant. Materials and Methods: 24 biopsy-proven intraprostatic radiotherapy failure Pts were used for this study. Each had post PPI (pPPI) dosimetry
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data determined from a post-implant CT (pCT) at one month post time of implant (ToI), MR imaging and complete pathology at time of recurrence (ToR). The prostate was contoured and the seeds were digitized on the MRI. In general, radiation dose will cause a decrease in prostate volume. In order to calculate the correct dosimetry, it is therefore necessary to recreate the original (larger) volume of the prostate and the relative positions of the seeds. An isotropic prostate expansion was implemented using the center of mass of the contours as the isocenter of the expansion. This model was validated on a patient where MR images were available both at 30 days and at the time of recurrence. The resulting isodoses were superimposed on the pCT. The prostate volume (PV) was divided in four zones, in each of three (base, mid-gland and apex) slices: anterior, posterior, left or right, thus resulting in 12 zones for mapping low radiation dose areas (coldspots). Coldspots were defined in 3 categories with respect to the apex, mid-gland and base: Diffusely cold, anteriorly cold and posteriorly cold. Results: The mean PV determined at ToI and ToR were 63.7 cm3 and 40.8 cm3, respectively. The mean time interval between ToI and ToR was 72.3 months. The mean D90 and V100 were 145.2 Gy and 94.9% at ToI vs. 96.5 Gy and 77.1% at ToR, showing that the values evaluated at ToR are significantly lower compared to the ToI. All patients but one patient had a coldspot at least one of their pathologically positive (pathþ) sextants. 77% of the positive (pathþ) sextants were identified as coldspots. Coldspots were more likely to be diffuse cranio-caudally (apex: 75.0%, mid-gland: 0%, base: 62.5%, and apexþbase: 54.1%. The mean number of pathþ and cold sextants were 1.8 and 4.8. The rates of anterior and posterior cold areas were: 12.5% and 25.0% for apex, 70.8% and 37.5% for mid-gland, 20.8% and 16.6% for the base. Conclusions: A model to expand the PV seen at ToR and project it back to the ToI was developed. The dose distribution inferred from the ToR imaging was used to identify coldspots. We found a relationship between biopsy positivity and coldspots: Pts with a biopsy-proven local failure (recurrence) had worse quality implants (lack of dosimetric coverage). This method can be used to determine if focal salvage brachytherapy would be beneficial for a patient who has experienced local failure following PPI therapy.
PO30 Interstitial High-Dose-Rate Brachytherapy Under Local Anesthesia for Early Stage Prostate Cancer: A Report of 546 Cases Rufus J. Mark, MD, Paul J. Anderson, MD, Robin S. Akins, MD, Murali Nair, PhD. Radiation Oncology, Joe Arrington Cancer Center, Lubbock, TX. 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 external beam radiation therapy. TRUS interstitial implant of the prostate has been traditionally performed under general or spinal anesthetic in an operating room. We report our results with a technique performed under local anesthesia in a department procedure room. Materials and Methods: Patients with T1 and T2 localized prostate cancer were judged to be candidates for TRUS guided interstitial implant. Conscious sedation consisted of intravenous Morphine (12e22 mg) and Versed (6e14 mg), or intravenous Demerol (25e250 mg) and Versed (3e12 mg), and Ativan (0e2 mg). Local anesthetic was given with a mixture of 1% Lidocaine, 0.25% Marcaine, 1:100,000 Epinephrine, and 4% Sodium Bicarbonate neutralizing solution (120 cc). Local anesthesia was given to a 5 x 5 cm perineal area to a depth of 10 cm under TRUS guidance. The implants were placed under mobile multi-plane prostate template (Radiation Therapy Products Prostate Template) guidance using from 3 to 4 planes, and 12 to 22 needles. Needle spacing was 1.0 cm. The implant procedure included sigmoidoscopy and cystoscopy. Results: Between 2002 and 2010, 546 TRUS-guided prostate implants were performed under local anesthesia. Median implant time was 45 minutes (range: 30 to 150 minutes). HDR treatment was given using the Nucletron afterloading system. The implant volume received 2,250 cGy in 3 fractions prescribed to the 100% isodose line, given over 24 hours. Urethral dose points (12e16) were followed, and limited to #105% of
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the prescription dose. The procedure was well tolerated, with all patients having completed the procedure. Four patients developed respiratory suppression, and required reversal with Narcan. All recovered uneventfully. Otherwise, there have been no acute complications to date. Conclusions: TRUS interstitial implant of the prostate under local anesthesia is feasible. Implant time, complications, cost, and scheduling convenience, compare favorably to general or spinal anesthetic technique. PO31 Androgen Deprivation Therapy for Salvage Treatment of PSA Only Recurrent Prostate Cancer After Interstitial High-Dose-Rate Brachytherapy for Early Stage Prostate Cancer: Median 6-Year Followup in 27 Patients Rufus J. Mark, MD, Paul J. Anderson, MD, Robin S. Akins, MD, Murali Nair, PhD. Radiation Oncology, Joe Arrington Cancer Center, Lubbock, TX. Purpose: Salvage treatment of biochemical recurrence after radiation implant is a subject of considerable controversy. Management options include PSA surveillance, radical prostatectomy, cryosurgery, external radiation therapy (XRT), intensity modulated radiation therapy (IMRT), and androgen deprivation therapy (ADT). Complication risks after radical prostatectomy, cryosurgery, XRT and IMRT salvage can be significant. We present our results in 27 patients treated with ADT for biochemical recurrence after high-dose-rate (HDR) implant. Materials and Methods: Between 1997 and 2010, 317 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 XRT, IMRT, or initial ADT. Median Gleason Score was 7 (range: 4 to 10). Median PSA was 9.3 (2.7 to 39.8). At last followup, 36 patients had developed PSA only relapse. After a discussion of management options, 27 patients elected salvage treatment with intermittent ADT, starting with Casodex. All patients started Casodex 50 mg qd with PSA !10. Results: With a median followup of 72 months (range: 6 months to 132 months), the PSA control rate on Casodex or Lupron was 81.5% (22/27). Five of these patients have become refractory to Casodex, and were switched to Lupron. Three of these patients remain controlled on Lupron. One patient entered a clinical trial for Chemotherapy. Two patients have died from metastatic prostate cancer. Two patients developed bone metastases. Side effects have been acceptable. One patient sustained a myocardial infarction, and a 2nd suffered a fractured hip. Conclusions: With median 6-year followup, ADT appears to be a reasonable salvage option for patients experiencing a PSA only relapse after HDR implant. PO32 HDR Brachytherapy With External Beam Radiotherapy and Androgen Deprivation Therapy for Prostate Cancer: Initial Six-Year Experience at St. George Cancer Care Centre Stacy L. Miller, MD1, Joseph Bucci, MD1, Yaw Chin, MD1, David Malouf, MD2. 1Radiation Oncology, St. George Cancer Care Centre, Sydney, NSW, Australia; 2Urology Sydney, Sydney, NSW, Australia. Purpose: In 2003, combination treatment for locally advanced prostate cancer with external beam radiation, HDR Brachytherapy boost, and androgen deprivation therapy was initiated at St. George Hospital in Sydney. 235 patients have been treated to date. The purpose of this study is to examine the outcomes of this treatment strategy with a focus on assessment of treatment toxicity and impact on quality of life. Early disease control outcomes will also be presented. Materials and Methods: From May 2003 to May 2009, 200 patients underwent treatment with HDR Brachytherapy (19.5Gy in 3 fractions or 18Gy in 2 fractions) followed by external beam radiotherapy (46Gy in 23 fractions). Ninety percent of patients were treated with androgen deprivation therapy. Eligibility criteria include localized intermediate and high risk prostate cancer, PSA up to 40, and fitness for surgery. Disease control and toxicity data were prospectively collected at baseline and
each subsequent followup including assessment of PSA, urinary, bowel, and sexual function, and quality of life. Biochemical control and survival data are also reported. Results: 200 patients, with a mean age of 65 years, were treated between May 2003 and May 2009. Of these, 50% had high risk disease. Median followup was 3 years. Early and late grade 3 urinary toxicity occurred in 8.5% and 12% respectively including a 7.5% risk of acute catheterization and a 5% risk of urethral stricture. Grade 3 rectal toxicity occurred in 4.5% with the majority of cases successfully treated with formalin or argon laser coagulation. There was no grade 4 urinary or bowel toxicity. At baseline, 45% of men had normal sexual function. Of these patients, 35% retained erectile function following treatment. Sexual function outcomes were related to duration of hormone use. 7.3% of patients have developed a biochemical recurrence and 3.3% have developed metastases. There has been one prostate cancer related death at 5.5 years post treatment. Conclusions: For the majority of men, this treatment is well tolerated and early disease control outcomes, including biochemical control, appear promising. This combination treatment is an effective method of dose escalation to improve outcomes for men with locally advanced prostate cancer, though long-term followup is required to confirm these findings.
PO33 The Impact of Significant Intraprostate Calcification on Dosimetry for 125I Brachytherapy Stacy L. Miller, MD1, Joseph Bucci, MD1, Brad M. Oborn, PhD2, David Malouf, MD3. 1Radiation Oncology, St. George Cancer Care Centre, Sydney, NSW, Australia; 2Medical Physics, Illawarra Cancer Care Centre, Wollongong, NSW, Australia; 3Urology Sydney, Sydney, NSW, Australia. Purpose: On ultrasound imaging of the prostate prior to prostate seed brachytherapy, some patients are found to have significant intraprostatic calcification. Due to the relatively increased density of calcification compared to prostate soft tissue, there is a potential for increased radiation attenuation which could potentially impact dosimetry and prostate cancer outcomes. The objective of this study is to assess whether or not intraprostatic calcification impacts dosimetry. Materials and Methods: Patients were identified who had significant intraprostatic calcification on ultrasound. Post implant CT scans were done for each patient and calcifications were contoured on each slice of the prostate volume. A Monte Carlo calculation (Geant4) was done for each case to assess dosimetry including the effect of the calcifications. This was then compared to dosimetric parameters calculated by the brachytherapy treatment planning software that does not take tissue heterogeneity into account. Results: Post operative dosimetry has been analyzed for three patients thus far. Each of these cases met dosimetric criteria for a favorable implant using traditional treatment planning software. With Monte Carlo analysis, however, the presence of intraprostatic calcification significantly impacted dosimetry for two of the three cases. For these two cases, post implant dosimetry became unfavorable when the impact of the calcification was considered. Analysis of six additional cases is pending. Conclusions: Early analysis shows that intraprostatic calcification may impact dosimetry of I-125 prostate brachytherapy. The dosimetric effect of the calcifications may depend on the calcification volume, shape, and location. Understanding the impact of significant intraprostatic calcification on radiation dosimetry is important as it could potentially impact treatment outcome.
PO34 Evaluation of Prostate Recurrences After Receiving a Combined External Beam and HDR Brachytherapy Boost Technique for Prostate Cancer Frank-Andre Siebert, PhD1, Borries Schlichting2, Peter Niehoff, MD1, Gyorgy Kovacs, MD, PhD2. 1Clinic of Radiotherapy, University Hospital of Schleswig-Holstein, Campus Kiel, Kiel, Germany; 2Interdisciplinary Brachytherapy Unit, University of Luebeck, Luebeck, Germany.
PO29 Inferring Postimplant Dosimetry and Determining Low Radiation Dose Volumes Using Images Obtained at the Time of Recurrence After Permanent Prostate Implant Brachytherapy: A Pragmatic Study Devan Krishnamurthy, PhD, Gilles Crehange, MD, J. Adam M. Cunha, PhD, Dilini Pinnaduwage, PhD, Barby Pickett, PhD, I-Chow Hsu, MD, Alexander Gottschalk, MD, Mack Roach III, MD, Jean Pouliot, PhD. Radiation Oncology, University of California San Francisco, San Francisco, CA. Purpose: Some patients (Pts) with a clinically localized prostate cancer who underwent prostate permenant-seed implant (PPI) have a biochemical failure. This recurrence could be correlated with low radiation dose volumes on the preoperative or postoperative PPI dosimetric plans. Unfortunately, 30-day post implant dosimetry information is not always available at time of recurrence. The purpose of this work is to establish a method for evaluating dosimetry at the time of implant using (1) an pelvic MR image at time of recurrence and (2) the recorded prostate volume at the time of implant. Materials and Methods: 24 biopsy-proven intraprostatic radiotherapy failure Pts were used for this study. Each had post PPI (pPPI) dosimetry
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data determined from a post-implant CT (pCT) at one month post time of implant (ToI), MR imaging and complete pathology at time of recurrence (ToR). The prostate was contoured and the seeds were digitized on the MRI. In general, radiation dose will cause a decrease in prostate volume. In order to calculate the correct dosimetry, it is therefore necessary to recreate the original (larger) volume of the prostate and the relative positions of the seeds. An isotropic prostate expansion was implemented using the center of mass of the contours as the isocenter of the expansion. This model was validated on a patient where MR images were available both at 30 days and at the time of recurrence. The resulting isodoses were superimposed on the pCT. The prostate volume (PV) was divided in four zones, in each of three (base, mid-gland and apex) slices: anterior, posterior, left or right, thus resulting in 12 zones for mapping low radiation dose areas (coldspots). Coldspots were defined in 3 categories with respect to the apex, mid-gland and base: Diffusely cold, anteriorly cold and posteriorly cold. Results: The mean PV determined at ToI and ToR were 63.7 cm3 and 40.8 cm3, respectively. The mean time interval between ToI and ToR was 72.3 months. The mean D90 and V100 were 145.2 Gy and 94.9% at ToI vs. 96.5 Gy and 77.1% at ToR, showing that the values evaluated at ToR are significantly lower compared to the ToI. All patients but one patient had a coldspot at least one of their pathologically positive (pathþ) sextants. 77% of the positive (pathþ) sextants were identified as coldspots. Coldspots were more likely to be diffuse cranio-caudally (apex: 75.0%, mid-gland: 0%, base: 62.5%, and apexþbase: 54.1%. The mean number of pathþ and cold sextants were 1.8 and 4.8. The rates of anterior and posterior cold areas were: 12.5% and 25.0% for apex, 70.8% and 37.5% for mid-gland, 20.8% and 16.6% for the base. Conclusions: A model to expand the PV seen at ToR and project it back to the ToI was developed. The dose distribution inferred from the ToR imaging was used to identify coldspots. We found a relationship between biopsy positivity and coldspots: Pts with a biopsy-proven local failure (recurrence) had worse quality implants (lack of dosimetric coverage). This method can be used to determine if focal salvage brachytherapy would be beneficial for a patient who has experienced local failure following PPI therapy.
PO30 Interstitial High-Dose-Rate Brachytherapy Under Local Anesthesia for Early Stage Prostate Cancer: A Report of 546 Cases Rufus J. Mark, MD, Paul J. Anderson, MD, Robin S. Akins, MD, Murali Nair, PhD. Radiation Oncology, Joe Arrington Cancer Center, Lubbock, TX. 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 external beam radiation therapy. TRUS interstitial implant of the prostate has been traditionally performed under general or spinal anesthetic in an operating room. We report our results with a technique performed under local anesthesia in a department procedure room. Materials and Methods: Patients with T1 and T2 localized prostate cancer were judged to be candidates for TRUS guided interstitial implant. Conscious sedation consisted of intravenous Morphine (12e22 mg) and Versed (6e14 mg), or intravenous Demerol (25e250 mg) and Versed (3e12 mg), and Ativan (0e2 mg). Local anesthetic was given with a mixture of 1% Lidocaine, 0.25% Marcaine, 1:100,000 Epinephrine, and 4% Sodium Bicarbonate neutralizing solution (120 cc). Local anesthesia was given to a 5 x 5 cm perineal area to a depth of 10 cm under TRUS guidance. The implants were placed under mobile multi-plane prostate template (Radiation Therapy Products Prostate Template) guidance using from 3 to 4 planes, and 12 to 22 needles. Needle spacing was 1.0 cm. The implant procedure included sigmoidoscopy and cystoscopy. Results: Between 2002 and 2010, 546 TRUS-guided prostate implants were performed under local anesthesia. Median implant time was 45 minutes (range: 30 to 150 minutes). HDR treatment was given using the Nucletron afterloading system. The implant volume received 2,250 cGy in 3 fractions prescribed to the 100% isodose line, given over 24 hours. Urethral dose points (12e16) were followed, and limited to #105% of
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the prescription dose. The procedure was well tolerated, with all patients having completed the procedure. Four patients developed respiratory suppression, and required reversal with Narcan. All recovered uneventfully. Otherwise, there have been no acute complications to date. Conclusions: TRUS interstitial implant of the prostate under local anesthesia is feasible. Implant time, complications, cost, and scheduling convenience, compare favorably to general or spinal anesthetic technique. PO31 Androgen Deprivation Therapy for Salvage Treatment of PSA Only Recurrent Prostate Cancer After Interstitial High-Dose-Rate Brachytherapy for Early Stage Prostate Cancer: Median 6-Year Followup in 27 Patients Rufus J. Mark, MD, Paul J. Anderson, MD, Robin S. Akins, MD, Murali Nair, PhD. Radiation Oncology, Joe Arrington Cancer Center, Lubbock, TX. Purpose: Salvage treatment of biochemical recurrence after radiation implant is a subject of considerable controversy. Management options include PSA surveillance, radical prostatectomy, cryosurgery, external radiation therapy (XRT), intensity modulated radiation therapy (IMRT), and androgen deprivation therapy (ADT). Complication risks after radical prostatectomy, cryosurgery, XRT and IMRT salvage can be significant. We present our results in 27 patients treated with ADT for biochemical recurrence after high-dose-rate (HDR) implant. Materials and Methods: Between 1997 and 2010, 317 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 XRT, IMRT, or initial ADT. Median Gleason Score was 7 (range: 4 to 10). Median PSA was 9.3 (2.7 to 39.8). At last followup, 36 patients had developed PSA only relapse. After a discussion of management options, 27 patients elected salvage treatment with intermittent ADT, starting with Casodex. All patients started Casodex 50 mg qd with PSA !10. Results: With a median followup of 72 months (range: 6 months to 132 months), the PSA control rate on Casodex or Lupron was 81.5% (22/27). Five of these patients have become refractory to Casodex, and were switched to Lupron. Three of these patients remain controlled on Lupron. One patient entered a clinical trial for Chemotherapy. Two patients have died from metastatic prostate cancer. Two patients developed bone metastases. Side effects have been acceptable. One patient sustained a myocardial infarction, and a 2nd suffered a fractured hip. Conclusions: With median 6-year followup, ADT appears to be a reasonable salvage option for patients experiencing a PSA only relapse after HDR implant. PO32 HDR Brachytherapy With External Beam Radiotherapy and Androgen Deprivation Therapy for Prostate Cancer: Initial Six-Year Experience at St. George Cancer Care Centre Stacy L. Miller, MD1, Joseph Bucci, MD1, Yaw Chin, MD1, David Malouf, MD2. 1Radiation Oncology, St. George Cancer Care Centre, Sydney, NSW, Australia; 2Urology Sydney, Sydney, NSW, Australia. Purpose: In 2003, combination treatment for locally advanced prostate cancer with external beam radiation, HDR Brachytherapy boost, and androgen deprivation therapy was initiated at St. George Hospital in Sydney. 235 patients have been treated to date. The purpose of this study is to examine the outcomes of this treatment strategy with a focus on assessment of treatment toxicity and impact on quality of life. Early disease control outcomes will also be presented. Materials and Methods: From May 2003 to May 2009, 200 patients underwent treatment with HDR Brachytherapy (19.5Gy in 3 fractions or 18Gy in 2 fractions) followed by external beam radiotherapy (46Gy in 23 fractions). Ninety percent of patients were treated with androgen deprivation therapy. Eligibility criteria include localized intermediate and high risk prostate cancer, PSA up to 40, and fitness for surgery. Disease control and toxicity data were prospectively collected at baseline and
each subsequent followup including assessment of PSA, urinary, bowel, and sexual function, and quality of life. Biochemical control and survival data are also reported. Results: 200 patients, with a mean age of 65 years, were treated between May 2003 and May 2009. Of these, 50% had high risk disease. Median followup was 3 years. Early and late grade 3 urinary toxicity occurred in 8.5% and 12% respectively including a 7.5% risk of acute catheterization and a 5% risk of urethral stricture. Grade 3 rectal toxicity occurred in 4.5% with the majority of cases successfully treated with formalin or argon laser coagulation. There was no grade 4 urinary or bowel toxicity. At baseline, 45% of men had normal sexual function. Of these patients, 35% retained erectile function following treatment. Sexual function outcomes were related to duration of hormone use. 7.3% of patients have developed a biochemical recurrence and 3.3% have developed metastases. There has been one prostate cancer related death at 5.5 years post treatment. Conclusions: For the majority of men, this treatment is well tolerated and early disease control outcomes, including biochemical control, appear promising. This combination treatment is an effective method of dose escalation to improve outcomes for men with locally advanced prostate cancer, though long-term followup is required to confirm these findings.
PO33 The Impact of Significant Intraprostate Calcification on Dosimetry for 125I Brachytherapy Stacy L. Miller, MD1, Joseph Bucci, MD1, Brad M. Oborn, PhD2, David Malouf, MD3. 1Radiation Oncology, St. George Cancer Care Centre, Sydney, NSW, Australia; 2Medical Physics, Illawarra Cancer Care Centre, Wollongong, NSW, Australia; 3Urology Sydney, Sydney, NSW, Australia. Purpose: On ultrasound imaging of the prostate prior to prostate seed brachytherapy, some patients are found to have significant intraprostatic calcification. Due to the relatively increased density of calcification compared to prostate soft tissue, there is a potential for increased radiation attenuation which could potentially impact dosimetry and prostate cancer outcomes. The objective of this study is to assess whether or not intraprostatic calcification impacts dosimetry. Materials and Methods: Patients were identified who had significant intraprostatic calcification on ultrasound. Post implant CT scans were done for each patient and calcifications were contoured on each slice of the prostate volume. A Monte Carlo calculation (Geant4) was done for each case to assess dosimetry including the effect of the calcifications. This was then compared to dosimetric parameters calculated by the brachytherapy treatment planning software that does not take tissue heterogeneity into account. Results: Post operative dosimetry has been analyzed for three patients thus far. Each of these cases met dosimetric criteria for a favorable implant using traditional treatment planning software. With Monte Carlo analysis, however, the presence of intraprostatic calcification significantly impacted dosimetry for two of the three cases. For these two cases, post implant dosimetry became unfavorable when the impact of the calcification was considered. Analysis of six additional cases is pending. Conclusions: Early analysis shows that intraprostatic calcification may impact dosimetry of I-125 prostate brachytherapy. The dosimetric effect of the calcifications may depend on the calcification volume, shape, and location. Understanding the impact of significant intraprostatic calcification on radiation dosimetry is important as it could potentially impact treatment outcome.
PO34 Evaluation of Prostate Recurrences After Receiving a Combined External Beam and HDR Brachytherapy Boost Technique for Prostate Cancer Frank-Andre Siebert, PhD1, Borries Schlichting2, Peter Niehoff, MD1, Gyorgy Kovacs, MD, PhD2. 1Clinic of Radiotherapy, University Hospital of Schleswig-Holstein, Campus Kiel, Kiel, Germany; 2Interdisciplinary Brachytherapy Unit, University of Luebeck, Luebeck, Germany.