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40 Urinary retention following ultrasound guided brachytherapy for prostate cancer: Incidence and risk factors
Pro ft~zred papers
circumferential in 4 patients. Tumour length was of 3 to less than 5 cm in 22 patients, of 5 to 9 cm in 18 patients and of more than 9 cm in 5 patients. Under direct rectoscopy, radio-opaque clips for positioning quality control of simulation and treatment applications were placed to mark the tumor proximal and distal margins, Planning was done on a CT simulator using a flexible endorectal applicator with 8 channels. Contoured tumor, applicator and endorectal clips are incorporated into digitally reconstructed radiographs or digitally composite radiographs to selectively enhance their visualization for daily treatment. A total dose of 26 Gy in 4 daily fractions of 6.5 Gy is prescribed at the tumor radial margin. Differential channel loading of the endorectal applicator is performed in order to achieve conformal dosimetry. Results: physical limiting factors are: a rectal lumen of more than 2cm and tumor thickness of less than 3 cm. A comparative study between central and multi-channel loading systems was done. The latter allows better conformal dose distribution to the tumor and lower dose to the distal rectal margin. The endorectal clips are essential to reproducing the treatment as planned at the CT simulator. At the time of surgery, no residual tumor was observed in 2/3 of the patients. Pathological tumor downsizing (defined as _>50% decrease in tumor size) was obtained in 90% of patients, with 33% of pTON0-1, and 33% microfoci residual tumor, Conclusion: advances in tumor imaging and 3D planning systems allow better tumor mapping and dose planning. The use of a remote afterloading brachytherapy delivery system in conjunction with a multi-channel loading endorectal applicator results in highly conformal radiation delivery. By combining these new modalities, tumor length and shape are no longer limiting factors for endoluminal brachytherapy. Our pathology results suggest that this new clinical application of endorectal brachytherapy may be a competitive therapeutic option in the treatment of advanced rectal cancer. 37
oral
Anal and rectal cancer: clinical experiences on P.D.R. brachytherapy G.B Pizzi Ospedale Civile Umberto I °, Unita' Operativa di Radioterapia Oncologica. Mestre-Venezia, Italy Introduction: since 1995, at the Radiotherapy Department of Umberto I° Hospital in Mestre-Venice, is available a P.D.R. Nucletron Micro-Selectron machine utilised in several clinical applications. This report analyses the preliminary experiences on the pulsed brachytherapy (P.D.R.) treatment of anal and rectal cancers. Material and methods: from March 1995 through December 2000, 39 patients affected with anal cancers and 17 with rectal tumours were treated by P.D.R. brachytherapy boost. Anal cancers: 8 patients in stage I, 22 in II, 7 in IliA and 2 in IIIB were treated by EBRT 30 Gy/19 days (with 5-Fluorouracil and Mitomycin C during the first 5 days). The PDR brachytherapy boost followed after 2 months. Rectal cancers: 17 patients, not operable for general reasons, (14 stage I, 3 stage II) were irradiated with pelvic EBRT (45Gy/25 fractions), followed 1 month later by PDR boost. Both these interstitials implants were performed with a rigid needle technique through a perineal approach using a template. By 4-6 guide needles we treated active lengths of 4-6 cm. The prescribed dose was 20 Gy at isodose reference according to the Paris System. The irradiation was given 24 hours per day. The dose rate/h, was always 90 cGy, the dwell positions were 2.5 mm, with 1 pulse/h, and a range of dwell time of 2.8-5 s. Results: acute and short time tolerance: 2 of 39 anal channel treated pts. presented a grade 2 anal rectal mucositis and 7 a grade 1. 4 of 17 rectal cancers pts. presented a grade 2 rectal mucositis and 4 a grade 1. Preliminary oncology evaluation: in the analysis of the oncological results we only considered the patients which had a follow-up of at least 2 years. 21 of 33 pts. treated for anal cancer are evaluable: 16 are alive and well, but 1 had surgical rescue for local relapse 11 mths after treatment. 5 died for local progression and/or distant metastasis (after 9, 9, 10, 18 mths). 9/17 are the evaluable pts treated for rectal cancer: 7 are alive and disease free, 1 died (7 mths later) for local progression and 1 for liver metastasis developed 27 mths after the treatment. Discussion: our preliminary results on the use of PDR in the treatment of anal and rectal cancer seem to confirm the suggested radiobiological equivalence between the pulsed and the low dose rate brachytherapy: we did not observe any increase in acute and short term toxicity in the anal and rectal treated cancers in comparison with the expected toxicity and with our previous experiences using low dose rate treatment. We can make the same considerations taking into account the early clinical results. Surely the PDR advances the LDR in the point of view of staff radioprotection and of the correction of the non optimal applications.
Saturday, 9 June 2001 SI3
PROSTATE CANCER 38
Recommendations on permanent seed implantation for localized prostate cancer J, Battermann 1, D. Ash 1, A. Flynn2. T. de Reijke2, P. Lavagnini 3, L. Blank 3 Ion behalf of GEC-ESTRO, 2on behalf of EAU, 3on behalf of EORTC There has been a dramatic rise in seed implants in the USA over the last 5 years and a similar increase is expected in Europe. These recommendations are intended to indicate the factors, which may be related to successful outcomes in permanent seed implantation for localized prostate cancer. Patient selection: one aspect to patient selection is to identify patients to have a good outcome in disease control and the other is functional outcome. Significant factors for (biochemical) disease free survival include initial PSA, Gleason score, stage and treatment technique (number of seeds). For functional outcome these factors are prostate volume and IPSS. Permanent implantation is contra-indicated for patients with a life expectancy <5 years, M1 status, recent TURP, bleeding disorders and volume >50cc. Facilities and equipment: an operating room, as for other sterile brachytherapy procedures, as well as a dedicated clinical team (radiation-oncologist, urologist, radiation physicist, technicians) and the license to handle radioactive material. The equipment includes stabilizing device with stepping unit and template, ultrasound system, planning system and disposables. Implantation procedure: a preplanning is advised for patient selection, dose calculation and the determination of the number of seeds to be inserted. Both iodine-125 and palladium-103 are used for permanent implantation. For 1-125 monotherapy a dose of 145 Gy is routinely prescribed, for Pd-103 115 Gy to compensate for the shorter half life. The actual implant is performed under (spinal) anesthesia in lithotopy position. To reduce mobility of the gland it is helpful to introduce two or three locking needles. Needles are placed under ultrasound guidance, avoiding the central area with the urethra. After completioin of the implant, the number of seeds may be checked by fluoroscopy. Post implant dosimetry is performed at about one month after implantation, using CT or MR scanning. Potential indices of implant quality are implanted volume, number of needles and seeds, total activity, D90, V100 and V150. However, there is sufficient long-term followup data to confirm the value of these indices. Radiation protection and follow-up: because of the low energy of the two isotopes, the dose rate to the skin is extremely small. It is advised, however, that small children and pregnant women should not come close to the patient during the first two months. Patients may void seeds and theoretically may also expel a seed with ejaculation. Follow-up should include history, rectal examination, PSA test and record of side effects (urinary, bowel, potency). Conclusion: many authors have demonstrated a consistent high quality'of implantation and good long term results in selected patients with localized prostate cancer. Imaging and software technology is developing rapidly and this may well influence techniques and indications. Considerable expertise and team work are necessary to achieve optimum results as well as keeping up to date with new advances. 39 oral I m a g e - f u s i o n based postimplant analysis in seed implanta-
tion. A. Polo, M. Marsiglia, O. DeCobelli, A. Vavassori, F. Cattani, G. Tosi, A. Guido, G. Vila, D. Orini, R. Treviganti, M. Bellomi, R. Orecchia European Institute of Oncology, Milano Introduction: both the American Brachytherapy Society and the American Association of Physics in Medicine (TG64) recommend the realization of a postimplant dosimetry in every prostate implantation. The dosimetric analysis is sensitively dependent upon the definition of the target volume. Therefore a consistent radiological interpretation of the target volume should be used and documented to facilitate future interpretation of dosimetric outcome. Computerized tomography (CT) is ideal for determining seed distribution but soft tissue anatomy is frequently not well visualized. Magnetic resonance (MR) images soft tissue well but seed visualization is problematic. Objective: we describe our method to corregistrate CT and MR images to exploit the advantages of both modalities when assessing the quality of a prostate seed implant and we present our dosimetric results comparing CTbased postplanning with CT-MRI-based postplanning. Material and methods: between October 1999 and February 2001, 60 patients with low risk prostate carcinoma have been treated at the EIO with 1125 (44 patients) or Pdl03 (16 patients) seed implantation. Our corregistration (image-fusion) protocol was used without difficulty in 30 consecutive patients and has the following steps: CT scan of the prostate after seed implantation, MR scan of the prostate after CT after seed implantation in the
circumferential in 4 patients. Tumour length was of 3 to less than 5 cm in 22 patients, of 5 to 9 cm in 18 patients and of more than 9 cm in 5 patients. Under direct rectoscopy, radio-opaque clips for positioning quality control of simulation and treatment applications were placed to mark the tumor proximal and distal margins, Planning was done on a CT simulator using a flexible endorectal applicator with 8 channels. Contoured tumor, applicator and endorectal clips are incorporated into digitally reconstructed radiographs or digitally composite radiographs to selectively enhance their visualization for daily treatment. A total dose of 26 Gy in 4 daily fractions of 6.5 Gy is prescribed at the tumor radial margin. Differential channel loading of the endorectal applicator is performed in order to achieve conformal dosimetry. Results: physical limiting factors are: a rectal lumen of more than 2cm and tumor thickness of less than 3 cm. A comparative study between central and multi-channel loading systems was done. The latter allows better conformal dose distribution to the tumor and lower dose to the distal rectal margin. The endorectal clips are essential to reproducing the treatment as planned at the CT simulator. At the time of surgery, no residual tumor was observed in 2/3 of the patients. Pathological tumor downsizing (defined as _>50% decrease in tumor size) was obtained in 90% of patients, with 33% of pTON0-1, and 33% microfoci residual tumor, Conclusion: advances in tumor imaging and 3D planning systems allow better tumor mapping and dose planning. The use of a remote afterloading brachytherapy delivery system in conjunction with a multi-channel loading endorectal applicator results in highly conformal radiation delivery. By combining these new modalities, tumor length and shape are no longer limiting factors for endoluminal brachytherapy. Our pathology results suggest that this new clinical application of endorectal brachytherapy may be a competitive therapeutic option in the treatment of advanced rectal cancer. 37
oral
Anal and rectal cancer: clinical experiences on P.D.R. brachytherapy G.B Pizzi Ospedale Civile Umberto I °, Unita' Operativa di Radioterapia Oncologica. Mestre-Venezia, Italy Introduction: since 1995, at the Radiotherapy Department of Umberto I° Hospital in Mestre-Venice, is available a P.D.R. Nucletron Micro-Selectron machine utilised in several clinical applications. This report analyses the preliminary experiences on the pulsed brachytherapy (P.D.R.) treatment of anal and rectal cancers. Material and methods: from March 1995 through December 2000, 39 patients affected with anal cancers and 17 with rectal tumours were treated by P.D.R. brachytherapy boost. Anal cancers: 8 patients in stage I, 22 in II, 7 in IliA and 2 in IIIB were treated by EBRT 30 Gy/19 days (with 5-Fluorouracil and Mitomycin C during the first 5 days). The PDR brachytherapy boost followed after 2 months. Rectal cancers: 17 patients, not operable for general reasons, (14 stage I, 3 stage II) were irradiated with pelvic EBRT (45Gy/25 fractions), followed 1 month later by PDR boost. Both these interstitials implants were performed with a rigid needle technique through a perineal approach using a template. By 4-6 guide needles we treated active lengths of 4-6 cm. The prescribed dose was 20 Gy at isodose reference according to the Paris System. The irradiation was given 24 hours per day. The dose rate/h, was always 90 cGy, the dwell positions were 2.5 mm, with 1 pulse/h, and a range of dwell time of 2.8-5 s. Results: acute and short time tolerance: 2 of 39 anal channel treated pts. presented a grade 2 anal rectal mucositis and 7 a grade 1. 4 of 17 rectal cancers pts. presented a grade 2 rectal mucositis and 4 a grade 1. Preliminary oncology evaluation: in the analysis of the oncological results we only considered the patients which had a follow-up of at least 2 years. 21 of 33 pts. treated for anal cancer are evaluable: 16 are alive and well, but 1 had surgical rescue for local relapse 11 mths after treatment. 5 died for local progression and/or distant metastasis (after 9, 9, 10, 18 mths). 9/17 are the evaluable pts treated for rectal cancer: 7 are alive and disease free, 1 died (7 mths later) for local progression and 1 for liver metastasis developed 27 mths after the treatment. Discussion: our preliminary results on the use of PDR in the treatment of anal and rectal cancer seem to confirm the suggested radiobiological equivalence between the pulsed and the low dose rate brachytherapy: we did not observe any increase in acute and short term toxicity in the anal and rectal treated cancers in comparison with the expected toxicity and with our previous experiences using low dose rate treatment. We can make the same considerations taking into account the early clinical results. Surely the PDR advances the LDR in the point of view of staff radioprotection and of the correction of the non optimal applications.
Saturday, 9 June 2001 SI3
PROSTATE CANCER 38
Recommendations on permanent seed implantation for localized prostate cancer J, Battermann 1, D. Ash 1, A. Flynn2. T. de Reijke2, P. Lavagnini 3, L. Blank 3 Ion behalf of GEC-ESTRO, 2on behalf of EAU, 3on behalf of EORTC There has been a dramatic rise in seed implants in the USA over the last 5 years and a similar increase is expected in Europe. These recommendations are intended to indicate the factors, which may be related to successful outcomes in permanent seed implantation for localized prostate cancer. Patient selection: one aspect to patient selection is to identify patients to have a good outcome in disease control and the other is functional outcome. Significant factors for (biochemical) disease free survival include initial PSA, Gleason score, stage and treatment technique (number of seeds). For functional outcome these factors are prostate volume and IPSS. Permanent implantation is contra-indicated for patients with a life expectancy <5 years, M1 status, recent TURP, bleeding disorders and volume >50cc. Facilities and equipment: an operating room, as for other sterile brachytherapy procedures, as well as a dedicated clinical team (radiation-oncologist, urologist, radiation physicist, technicians) and the license to handle radioactive material. The equipment includes stabilizing device with stepping unit and template, ultrasound system, planning system and disposables. Implantation procedure: a preplanning is advised for patient selection, dose calculation and the determination of the number of seeds to be inserted. Both iodine-125 and palladium-103 are used for permanent implantation. For 1-125 monotherapy a dose of 145 Gy is routinely prescribed, for Pd-103 115 Gy to compensate for the shorter half life. The actual implant is performed under (spinal) anesthesia in lithotopy position. To reduce mobility of the gland it is helpful to introduce two or three locking needles. Needles are placed under ultrasound guidance, avoiding the central area with the urethra. After completioin of the implant, the number of seeds may be checked by fluoroscopy. Post implant dosimetry is performed at about one month after implantation, using CT or MR scanning. Potential indices of implant quality are implanted volume, number of needles and seeds, total activity, D90, V100 and V150. However, there is sufficient long-term followup data to confirm the value of these indices. Radiation protection and follow-up: because of the low energy of the two isotopes, the dose rate to the skin is extremely small. It is advised, however, that small children and pregnant women should not come close to the patient during the first two months. Patients may void seeds and theoretically may also expel a seed with ejaculation. Follow-up should include history, rectal examination, PSA test and record of side effects (urinary, bowel, potency). Conclusion: many authors have demonstrated a consistent high quality'of implantation and good long term results in selected patients with localized prostate cancer. Imaging and software technology is developing rapidly and this may well influence techniques and indications. Considerable expertise and team work are necessary to achieve optimum results as well as keeping up to date with new advances. 39 oral I m a g e - f u s i o n based postimplant analysis in seed implanta-
tion. A. Polo, M. Marsiglia, O. DeCobelli, A. Vavassori, F. Cattani, G. Tosi, A. Guido, G. Vila, D. Orini, R. Treviganti, M. Bellomi, R. Orecchia European Institute of Oncology, Milano Introduction: both the American Brachytherapy Society and the American Association of Physics in Medicine (TG64) recommend the realization of a postimplant dosimetry in every prostate implantation. The dosimetric analysis is sensitively dependent upon the definition of the target volume. Therefore a consistent radiological interpretation of the target volume should be used and documented to facilitate future interpretation of dosimetric outcome. Computerized tomography (CT) is ideal for determining seed distribution but soft tissue anatomy is frequently not well visualized. Magnetic resonance (MR) images soft tissue well but seed visualization is problematic. Objective: we describe our method to corregistrate CT and MR images to exploit the advantages of both modalities when assessing the quality of a prostate seed implant and we present our dosimetric results comparing CTbased postplanning with CT-MRI-based postplanning. Material and methods: between October 1999 and February 2001, 60 patients with low risk prostate carcinoma have been treated at the EIO with 1125 (44 patients) or Pdl03 (16 patients) seed implantation. Our corregistration (image-fusion) protocol was used without difficulty in 30 consecutive patients and has the following steps: CT scan of the prostate after seed implantation, MR scan of the prostate after CT after seed implantation in the