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Torrence M Wilson

Publications and source records attributed to Torrence M Wilson.

8 recordsLinked to original sources
PubMed2006

Permanent prostate brachytherapy: pathologic implications as assessed on radical prostatectomy specimens of broadening selection criteria for monotherapy.

OBJECTIVES: To assess the impact of clinical selection criteria on pathologic features among patients treated by radical retropubic prostatectomy and to evaluate the implications of broadening eligibility for permanent prostate brachytherapy monotherapy. METHODS: A consecutive series of 423 patients with prostate cancer, who underwent diagnostic biopsy and subsequent radical retropubic prostatectomy, were selected for this study. Four subgroups were defined using the American Brachytherapy Society selection criteria, including prostate size limits (group 1), no prostate size limits (group 2A), a modified set of criteria (group 2B), and clinical Stage T1-T2 (group 3). The rates of extraprostatic extension, seminal vesicle invasion, and lymph node involvement were compared. RESULTS: Adverse pathologic features at radical retropubic prostatectomy were noted in 8 (9.3%) of 86 patients in group 1, 11 (5.6%) of 195 patients in group 2A, 35 (12.0%) of 292 patients in group 2B, and 90 (21.8%) of 413 patients in group 3. The rates of extraprostatic extension, seminal vesicle invasion, and lymph node involvement appeared comparable among groups 1 (5.8%, 3.5%, and 0.0%, respectively), 2A (3.6%, 2.1%, and 0.0%, respectively), and 2B (6.9%, 3.8%, and 1.4%, respectively), but were greater in group 3 (9.7%, 7.8%, and 4.4%, respectively). CONCLUSIONS: Judicious broadening of the clinical selection criteria may allow a greater number of patients to be eligible for permanent prostate brachytherapy monotherapy by including patients whose risk of having adverse pathologic features is comparable to that of patients currently deemed suitable for permanent prostate brachytherapy monotherapy. Prospective assessment of oncologic outcomes of such an approach is required.

Adult↗
PubMed2004

Prostate volume measurement by transrectal ultrasound and computed tomography before and after permanent prostate brachytherapy.

PURPOSE: To quantify prostate volume (pvol) changes with transrectal ultrasound (TRUS) immediately after permanent prostate brachytherapy (PPB) and to correlate these changes with postimplant computed tomography (CT) volumetrics. To provide data relevant to evaluating the potential of TRUS-based image fusion for intraoperative dosimetry. METHODS AND MATERIALS: Between July 2000 and January 2003, 177 patients underwent (125)I PPB monotherapy at our institution, and 165 patients provided research authorization. A total of 136 patients (82%) completed 4 imaging studies: planning TRUS, intraoperative pre- and postimplant TRUS, and CT. RESULTS: Mean planning TRUS pvol was 38.7 +/- 11.7 cc standard deviation (SD), 95% confidence interval (CI) (36.7, 40.7). Mean intraoperative TRUS pvol preimplant was 37.1 +/- 11.7 cc SD, 95% CI (35.1, 39.0), and postimplant was 44.5 +/- 15.1 cc SD, 95% CI (42.0, 47.1). The mean ratio of postimplant:preimplant intraoperative TRUS pvols was 1.2 +/- 0.2 SD, 95% CI (1.18, 1.24), and the difference in mean values was 7.5 cc (p < 0.0001). CT performed within 1 day revealed a mean pvol of 47.9 +/- 15.7 cc SD, 95% CI (45.2, 50.5). The mean volumetric ratio of CT to postimplant TRUS pvol was 1.13 +/- 0.36, 95% CI (1.07-1.19). CONCLUSIONS: Whereas mean preimplant step-section TRUS pvol measurements are similar, postimplant TRUS and CT measurements have greater variability that depend on initial pvol. CT-based pvol measurements determined a mean of 10.6 hours after implant were more likely to be identical to those of immediate postimplant TRUS in prostates >33 cc. These data are relevant for establishing accuracy in image-fusion based approaches being investigated for real-time intraoperative PPB dosimetry.

Analysis of Variance↗
PubMed2004

Radioactive seed migration to the chest after transperineal interstitial prostate brachytherapy: extraprostatic seed placement correlates with migration.

PURPOSE: To examine the incidence of seed migration detected on chest X-ray and to identify the predictors associated with its occurrence. METHODS AND MATERIALS: Between May 1998 and April 2000, 102 patients underwent permanent prostate brachytherapy at our institution and 100 were eligible for the study. Chest X-rays obtained at follow-up were examined for the number and location of seeds. The patient and treatment variables potentially associated with the occurrence and number of seed migrations were analyzed. RESULTS: One or more seeds were identified on the chest X-rays of 55 (55%) of 100 patients. The mean number of intrathoracic seeds in patients with migration was 2.2 (range, 1-10), and the proportion of seeds that migrated to the thorax was 0.98%. The rate of extraprostatic seeds planned was 43.9%, and postimplant CT identified 37.9% in such a location. The number of seeds planned for extraprostatic placement and below the apex were statistically significant (alpha = 0.05) predictors in univariate logistic analysis. Multivariate analysis revealed the planned number of extraprostatic seeds as the only statistically significant predictor (p = 0.04). CONCLUSION: Extraprostatic placement of loose seeds is associated with an increased likelihood for, and frequency of, seed migration to the thorax. Nonetheless, the small proportion of implanted seeds that migrated (<or=1%) is highly unlikely to have significant dosimetric consequences.

Aged↗
PubMed2003

Radiation exposure to operating room personnel during transperineal interstitial permanent prostate brachytherapy.

PURPOSE: To identify factors associated with radiation exposure (RE) to operating room personnel during transperineal interstitial permanent prostate brachytherapy (TIPPB). METHODS AND MATERIALS: Between May 1998 and December 2000, 155 patients underwent TIPPB with fluoroscopic and ultrasound guidance. Data for each case included: operating room time (OT), anesthesia time (AT), fluoroscopy time (FT), number and type of seed implanted, total seed activity, and resident participation. RESULTS: Personnel RE per case, FT, OT, and AT decreased as case number increased. Whole body badge dose per case decreased from a mean of 0.15+/-0.01 mSv (15+/-1 mrem) in 1998 to 0.074+/-0.011 mSv (7+/-1 mrem) in 2000. Average FT per case decreased from a mean of 17:27 min (range, 10:40-28:23) in 1998 to 12:08 min (range, 6:40-31:00) in 2000. Resident participation was associated with increased FT. Mean whole body and ring badge doses for the treating radiation oncologist were 0.0076 mSv/min (0.76 mrem/min) and 0.05 mSv/min (5.26 mrem/min) of FT, respectively. CONCLUSIONS: FT was the predominant factor that related to RE during TIPPB. Treating radiation oncologists were exposed to less than 20 mSv per 100 cases, significantly less than other fluoroscopically guided procedures. Nonetheless, appropriate radiation exposure precautions during TIPPB should continue.

Body Burden↗
PubMed2003

Treatment of organ confined prostate cancer with third generation cryosurgery: preliminary multicenter experience.

PURPOSE: Cryosurgical ablation of the prostate is 1 approach to the treatment of localized prostate cancer. Third generation cryosurgery uses gas driven probes that allow for a decrease in probe diameter to 17 gauge (1.5 mm). The safety, morbidity and preliminary prostate specific antigen (PSA) results of 122 cases are reported. MATERIALS AND METHODS: A total of 106 patients have undergone percutaneous cryosurgery using a brachytherapy template with at least 12 months of PSA followup. Immediate and delayed morbidities were evaluated. PSA results at 3 and 12 months were recorded, and failure was defined as the inability to reach a nadir of 0.4 ng/ml or less. RESULTS: Complications in patients undergoing primary cryosurgery included tissue sloughing (5%), incontinence (pads, 3%), urge incontinence/no pads (5%), transient urinary retention (3.3%) and rectal discomfort (2.6%). There were no cases of fistulas or infections. Postoperative impotence was 87% in previously potent patients. For patients who underwent salvage cryosurgery there were no fistulas reported and 2 (11%) patients required pads after salvage cryosurgery. A total of 96 (81%) patients achieved a PSA nadir of 0.4 ng/ml or less at 3 months of followup, while 79 of 106 (75%) remained free from biochemical recurrence at 12 months. A total of 42 (78%) low risk patients (Gleason score 7 or less and PSA 10 or less) remained with a PSA of 0.4 ng/ml or less at 12 months of followup, compared to 37 (71%) high risk patients. All patients were discharged within 24 hours. CONCLUSIONS: After a followup of 1 year 3rd generation cryosurgery appears to be well tolerated and minimally invasive. The use of ultrathin needles through a brachytherapy template allows for a simple percutaneous procedure and a relatively short learning curve. A prospective multicenter trial is ongoing to determine the long-term efficacy of this technique.

Aged↗
PubMed2002

The relevance of prostatectomy findings for brachytherapy selection in patients with localized prostate carcinoma.

BACKGROUND: The efficacy of brachytherapy for patients with localized prostate carcinoma depends on adequate radiotherapeutic coverage of the primary tumor and its subclinical extraprostatic extensions. Predictive models based on pretherapy factors may be useful to estimate the likelihood for clinically relevant extraprostatic disease and may be incorporated into selection criteria for this procedure. METHODS: Multivariate logistic regression model building was performed using pretherapy factors in 2905 surgically staged patients with localized prostate carcinoma to estimate the probability of seminal vesicle and/or lymph node involvement. Bootstrap methods were employed to assess the stability of the final model parameters and to determine the sensitivity and specificity of the final model. RESULTS: Clinical tumor classification, biopsy Gleason score groupings, and serum prostate specific antigen (PSA) levels were associated with seminal vesicle and/or pelvic lymph node involvement. These factors were incorporated into a multivariate model that predicted for these adverse histopathologic features. Allowing for up to a 10% likelihood for seminal vesicle and/or pelvic lymph node involvement, patients with tumors classified as T1c-T2a, Gleason scores of 2-6, and PSA < or = 16 ng/mL; or with tumors classified as T1c-T2a, Gleason scores of 7-10, and PSA < or = 4 ng/mL; or with tumors classified as T2b-T2c, Gleason scores of 2-6, and PSA < or = 6 ng/mL would be potential candidates for brachytherapy alone. CONCLUSIONS: The predictive model presented may provide criteria whereby an adequately performed prostate brachytherapy procedure is expected to encompass the intraprostatic and adjacent extraprostatic disease. Prostate brachytherapy alone may be considered in these circumstances, whereas the addition of external beam radiotherapy may be reserved for patients with disease that is apt to extend beyond the brachytherapy target volume.

Brachytherapy↗
PubMedDate not supplied

Prostate volume before and after permanent prostate brachytherapy in patients receiving neoadjuvant androgen suppression.

PURPOSE: Limited duration neoadjuvant cytoreductive hormonal therapy (NHT) is used before the definitive radiotherapeutic management of prostate cancer to decrease target volume size and/or to decrease urinary obstructive symptoms. The purpose of this study is to examine the effect of NHT on prostate volume before permanent prostate brachytherapy (PPB) and on prostatic edema after PPB. METHODS AND MATERIALS: Between May 1998 and February 2004, 408 patients underwent PPB at our institution and provided research authorization for the use of their records. Of these, 122 (30%) underwent NHT. Of the 122, 78 (64%) underwent transrectal ultrasound before the start of NHT. Patients undergoing PPB who received NHT were compared with a similar non-NHT group (N = 286). Detailed measurements of prostate volume were performed by transrectal ultrasound before and after NHT, if applicable. In addition, intraoperative preimplantation transrectal ultrasound and post-implantation transrectal ultrasound were also performed. Post-implantation computed tomography was per formed within 1 day of PPB. RESULTS: The mean duration of NHT was 4.0 +/- 1.1 months (range, 1-8 months). The mean prostate volume before NHT was 63.3 +/- 22.8 cc (range, 19-138 cc), and after NHT (before PPB), it was 41.6 +/- 16.4 cc (18-98 cc). The median prostate volume decrease after NHT was 22.7 cc or 34.9%. There was no significant difference in the degree of postimplantation prostate edema, as measured by the postimplantation to preimplantation ratio (1.18 +/- 0.05 [range, 0.8-1.9]) for the NHT group and 1.21 +/- 0.03 (range, 0.8-1.9) for the non-NHT group (P = 0.5). CONCLUSIONS: Prostate volume decreased by approximately one third after 4 months of NHT. NHT did not affect the degree of post-PPB prostatic edema.

Aged↗