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The effect of anatomic and dosimetric variables on urinary obstruction following permanent i-125 prostate brachytherapy
294
I. J. Radiation Oncology
● Biology ● Physics
Volume 51, Number 3, Supplement 1, 2001
Conclusion: In our study sample including both conformal and IMRT patients, the volume of rectum receiving the prescribed radiation dose (the equivalent of 78 Gy) is an independent predictor of late rectal bleeding. The percent of rectal volume receiving the full dose was not. Using actual volume rather than percent volume also avoids the dependence on the extent of rectal volume contours. We recommend 15 cc as the cut-off of the rectal volume not to exceed the prescription dose. The rectal bleeding rate at 2 years for cases with ⱕ15 cc receiving full dose was only 5%.
2134
The Effect of Anatomic and Dosimetric Variables on Urinary Obstruction Following Permanent I-125 Prostate Brachytherapy
M.A. Elshaikh1, C. Patel1, K. Angermeier2, J. Ulchaker2, E.A. Klein2, M.A. Chidel1, A. Wilkinson1, C.A. Reddy1, J.P. Ciezki1 1 Radiation Oncology, Cleveland Clinic Foundation, Cleveland, OH, 2Urology, Cleveland Clinic Foundation, Cleveland, OH Purpose: One of the most severe side effects of I-125 prostate seed implant is urinary retention requiring intermittent self-catheterization (ISC). In this study, we correlated the anatomic and post implant dosimetric parameters to the rate of ISC. Material and Methods: The records of 402 patients with a median age of 69 years treated with I-125 prostate seed implant from 1996-2001 were reviewed for the use of ISC. The records were examined for the anatomic/procedural factors: prostate volume, number of needles used, and prostate length. The following post-implant dosimetric information was also retrieved: V100, V150, V200, V300, V400, D90, and D100. Correlations were assessed using logistic regression analysis. Results: Forty-four patients had to use ISC (10.9%). The mean and median duration of ISC in weeks were 11.9 and 6 respectively. Using univariate analysis, prostate length and prostate volume were statistically significant predictors of ISC after I-125 prostate seed implant with p-values of 0.0002 and 0.0042, respectively. With multivariate analysis, only prostate length was a statistically significant predictor for ISC following I-125 prostate seed implant with a p-value of 0.0095. Conclusion: Prostate length is an important predictor for intermittent self-catheterization after I-125 prostate seed implant; it may be used to counsel patients pre-operatively.
2135
A Comparison of Biochemical Outcome Following Salvage Prostatectomy or Cryosurgery for Locally Recurrent Prostate Cancer after Radiation Therapy
L.L. Pisters1, B.C. Leibovich2, J. Izawa1, M.L. Blute2, L. Madsen1, S. Scott1, A.C. von Eschenbach1, J. Slezak2, H. Zincke2 1 Urology, M. D. Anderson Cancer Center, Houston, TX, 2Urology, Mayo Clinic, Rochester, MN Purpose: There are limited options for treating localized recurrence of prostate cancer after radiation therapy. There is minimal comparative data on outcomes for different therapeutic modalities. Our aim was to compare outcomes between contemporary series of salvage cryosurgery patients and salvage radical prostatectomy (RP) patients. Materials and Methods: We conducted a retrospective review of salvage cryosurgery cases and salvage radical prostatectomy cases from two institutions. Patients with pre-salvage treatment PSA ⬎10 and recurrence Gleason score ⬎8 were excluded to minimize bias and discrepancy between the groups and to limit the analysis to those patients most likely to be cured by aggressive further local therapy. Fifty-six salvage prostatectomy and 60 salvage cryosurgery cases fit the criteria for evaluation. None of the patients received androgen deprivation therapy until post-salvage biochemical failure. Clinical and laboratory factors, as well as the rate of prostate cancer death and biochemical progression, were compared between the treatment groups. To minimize bias, a uniform definition of biochemical failure (2 rises in PSA after nadir) was applied to both groups. Results: Mean follow-up was 5.1 years for the cryosurgery group and 4.6 years for the RP group. Median PSA prior to retreatment after radiation failure was 5.1 for the cryosurgery patients and 4.1 for the RP patients. Death due to prostate cancer occurred in 5 cryosurgery patients and 3 RP patients (p⫽0.65). Biochemical progression occurred in 40/60 (67%)cryosurgery patients and 16/56 (29%) RP patients (p⫽0.0002). Conclusion: Radical prostatectomy provides significantly lower rates of biochemical progression than cryosurgery for patients that have local recurrence of prostate cancer after radiation therapy.
I. J. Radiation Oncology
● Biology ● Physics
Volume 51, Number 3, Supplement 1, 2001
Conclusion: In our study sample including both conformal and IMRT patients, the volume of rectum receiving the prescribed radiation dose (the equivalent of 78 Gy) is an independent predictor of late rectal bleeding. The percent of rectal volume receiving the full dose was not. Using actual volume rather than percent volume also avoids the dependence on the extent of rectal volume contours. We recommend 15 cc as the cut-off of the rectal volume not to exceed the prescription dose. The rectal bleeding rate at 2 years for cases with ⱕ15 cc receiving full dose was only 5%.
2134
The Effect of Anatomic and Dosimetric Variables on Urinary Obstruction Following Permanent I-125 Prostate Brachytherapy
M.A. Elshaikh1, C. Patel1, K. Angermeier2, J. Ulchaker2, E.A. Klein2, M.A. Chidel1, A. Wilkinson1, C.A. Reddy1, J.P. Ciezki1 1 Radiation Oncology, Cleveland Clinic Foundation, Cleveland, OH, 2Urology, Cleveland Clinic Foundation, Cleveland, OH Purpose: One of the most severe side effects of I-125 prostate seed implant is urinary retention requiring intermittent self-catheterization (ISC). In this study, we correlated the anatomic and post implant dosimetric parameters to the rate of ISC. Material and Methods: The records of 402 patients with a median age of 69 years treated with I-125 prostate seed implant from 1996-2001 were reviewed for the use of ISC. The records were examined for the anatomic/procedural factors: prostate volume, number of needles used, and prostate length. The following post-implant dosimetric information was also retrieved: V100, V150, V200, V300, V400, D90, and D100. Correlations were assessed using logistic regression analysis. Results: Forty-four patients had to use ISC (10.9%). The mean and median duration of ISC in weeks were 11.9 and 6 respectively. Using univariate analysis, prostate length and prostate volume were statistically significant predictors of ISC after I-125 prostate seed implant with p-values of 0.0002 and 0.0042, respectively. With multivariate analysis, only prostate length was a statistically significant predictor for ISC following I-125 prostate seed implant with a p-value of 0.0095. Conclusion: Prostate length is an important predictor for intermittent self-catheterization after I-125 prostate seed implant; it may be used to counsel patients pre-operatively.
2135
A Comparison of Biochemical Outcome Following Salvage Prostatectomy or Cryosurgery for Locally Recurrent Prostate Cancer after Radiation Therapy
L.L. Pisters1, B.C. Leibovich2, J. Izawa1, M.L. Blute2, L. Madsen1, S. Scott1, A.C. von Eschenbach1, J. Slezak2, H. Zincke2 1 Urology, M. D. Anderson Cancer Center, Houston, TX, 2Urology, Mayo Clinic, Rochester, MN Purpose: There are limited options for treating localized recurrence of prostate cancer after radiation therapy. There is minimal comparative data on outcomes for different therapeutic modalities. Our aim was to compare outcomes between contemporary series of salvage cryosurgery patients and salvage radical prostatectomy (RP) patients. Materials and Methods: We conducted a retrospective review of salvage cryosurgery cases and salvage radical prostatectomy cases from two institutions. Patients with pre-salvage treatment PSA ⬎10 and recurrence Gleason score ⬎8 were excluded to minimize bias and discrepancy between the groups and to limit the analysis to those patients most likely to be cured by aggressive further local therapy. Fifty-six salvage prostatectomy and 60 salvage cryosurgery cases fit the criteria for evaluation. None of the patients received androgen deprivation therapy until post-salvage biochemical failure. Clinical and laboratory factors, as well as the rate of prostate cancer death and biochemical progression, were compared between the treatment groups. To minimize bias, a uniform definition of biochemical failure (2 rises in PSA after nadir) was applied to both groups. Results: Mean follow-up was 5.1 years for the cryosurgery group and 4.6 years for the RP group. Median PSA prior to retreatment after radiation failure was 5.1 for the cryosurgery patients and 4.1 for the RP patients. Death due to prostate cancer occurred in 5 cryosurgery patients and 3 RP patients (p⫽0.65). Biochemical progression occurred in 40/60 (67%)cryosurgery patients and 16/56 (29%) RP patients (p⫽0.0002). Conclusion: Radical prostatectomy provides significantly lower rates of biochemical progression than cryosurgery for patients that have local recurrence of prostate cancer after radiation therapy.