Jitendra Roy

Tumor control and morbidity following transperineal iodine 125 implantation for stage T1/T2 prostatic carcinoma.

PURPOSE To quantify disease progression and morbidity following computer tomography (CT)-based transperineal iodine 125 prostate implantation. METHODS Ninety-two patients with clinical stage T1 or T2, Gleason score 2 to 7/10, prostatic carcinoma had outpatient, CT-based transperineal 125I prostate implantation and were monitored for 1 to 7 years (median, 3). The prescribed minimum radiation dose was 140 to 160 Gy. Lymph node dissection and postimplantation prostatic biopsies were not routinely performed. RESULTS In 46% of patients, radiation-related urinary symptoms were substantial enough at 1 month following implantation to require medication. Radiation-related urinary symptoms gradually resolved. Two years after implantation, 14% of patients had persistent urinary symptoms of Radiation Therapy Oncology Group (RTOG) > or = grade 2. Eight percent of patients underwent a transurethral resection of the prostate (TURP) within 2 years of implantation. Five patients developed radiation-induced rectal ulcerations. Of 56 patients who were sexually potent preimplantation, 86% retained potency at 3 years. Twenty-five patients had biochemical disease progression. The overall actuarial freedom from biochemical failure rate at 4 years following implantation was 63%. In Cox proportional hazards multivariate analysis, the strongest predictor of failure was prostate-specific antigen (PSA) level less than or greater than 10 ng/mL (P = .005), followed by Gleason score (2 to 4 v 5 to 7, P = .08) and stage (T1 v T2, P = .09). CONCLUSION The 5-year biochemical freedom-from-progression rates following transperineal 125I implantation are comparable with those achieved with prostatectomy. The morbidity has decreased with increased physician experience.

Dosimetry guidelines to minimize urethral and rectal morbidity following transperineal I-125 prostate brachytherapy

PURPOSE To establish dosimetry guidelines to minimize urethral and rectal morbidity following permanent I-125 prostatic brachytherapy. METHODS AND MATERIALS Dosimetric parameters were correlated with long-term morbidity for 65 patients following transperineal I-125 implantation for Stage T1/T2 prostatic carcinoma. The prescribed minimum prostatic dose was 150 Gy. The median total activity used was 48 mCi (range: 32-77 mCi). Patients were followed for 1-5 years (median follow-up: 2 years). Postimplant computerized tomography (CT)-based dosimetry was performed for 45 patients. Morbidity was evaluated using a modification of the RTOG grading system, with a scale of grade 0-5. RESULTS The incidence of grades 2 and 3 urinary morbidity was associated with the maximum central urethral dose (p = 0.03), and with the length of urethra that received greater than 400 Gy (p = 0.07). Patients with larger prostates had more long-term urinary morbidity (p = 0.06). Rectal bleeding (RTOG grade 1) or ulceration (RTOG grade 2) was associated with irradiation of the rectal wall to doses in excess of 100 Gy (p = 0.02). There was no relationship between the matched peripheral dose (MPD), mCi/source or total mCi implanted and long-term morbidity. CONCLUSIONS Postimplant, CT-based dosimetry can predict which patients are at higher risk of radiation-related morbidity. More simplistic parameters including the MPD, total activity implanted, or mCi/source, had no relationship with morbidity. To decrease the risk of long-term morbidity, an effort should be made to keep the central urethral dose below 400 Gy, and the rectal surface dose below 100 Gy.

Treatment-related symptoms during the first year following transperineal 125I prostate implantation

PURPOSE To summarize the urinary, rectal, and sexual symptoms occurring during the first 12 months following 125I prostatic implantation. METHODS AND MATERIALS Thirty-one patients with Stage T1 or T2 prostatic carcinoma were evaluated for morbidity following computed tomography-guided transperineal 125I implants from 1988 to 1991. The median total activity used was 47 mCi (range 35-73 mCi). Toxicity was evaluated using a modification of the Radiation Therapy Oncology Group grading system. RESULTS Nocturia was the most common treatment-related symptom, reported by 80% of patients within 2 months after implantation, and persisted at 12 months in 45% of the patients. Mild dysuria developed in 48% of patients within 2 months of implantation; two patients needed analgesics for their dysuria. Terazosin hydrochloride (2-10 mg qd) provided subjective improvement of urinary symptoms in seven of eight patients in whom it was tried. Rectal urgency, soft stools, and increased frequency of bowel movements was reported by 25% of the patients within 1-2 months after implantation. The incidence of asymptomatic rectal bleeding or ulceration occurring at any time after implantation was 47%, but resolved in all patients with expectant treatment. Self-limited ulceration of the rectal mucosal occurred in 16%, but only one patient developed a prostato-rectal fistula, managed with an ileal conduit. Five of the 18 potent patients experienced discomfort on erection or ejaculation, beginning within several weeks of their implant. The discomfort resolved within 6 months in three of the patients, but persisted for 18 and 24 months in the other two. CONCLUSION 125I implantation, as performed in this series, is generally associated with only mild-moderate genitourinary and rectal symptoms that may persist 6 months or more after implantation. Prostatic carcinoma, Brachytherapy, Morbidity.

A CT-based evaluation method for permanent implants: application to prostate

A computerized tomography-based 3-dimensional evaluation scheme, using semi-automatic seed localization from transverse computerized tomography-images, has been developed for permanent implants. The treatment isodose contour is generated at each scan plane and overlaid on the corresponding target contour for coverage visualization. Volume and surface dose histograms are generated for the target and neighboring normal structures. Dose inhomogeneity within the target is also estimated from the full-width at half maximum of the differential volume dose histogram. The matched peripheral dose is calculated from the ellipsoidal volume approximation for the target. The present evaluation method has been applied here to 10 actual permanent I-125 prostatic implantations. Coverages by 150 Gy and 100 Gy levels are found to range from 78-96% and 91-99% of the target volume, respectively. The average matched peripheral dose is found to be about two times the average peripheral dose (the dose encompassing 99% target) and about three times the average minimum peripheral dose (the dose encompassing 100% target). The dose inhomogeneities within the target volume, in these 10 cases, range from 220-420 Gy.

Short-term freedom from disease progression after I-125 prostate implantation

PURPOSE To evaluate short-term clinical and chemical disease progression following computed tomography (CT)-based transperineal I-125 prostate implantation. METHODS AND MATERIALS Sixty-two patients with clinical Stage T1 or T2 prostatic carcinoma had outpatient, CT-based transperineal I-125 prostate implantation and have been followed for 6-55 months (median: 19 months). Fifty-six patients had an elevated prostate specific antigen (PSA) before implantation (> 4.0 ng/mL). Twenty patients had well-differentiated tumors, 39 were moderately differentiated, 2 were poorly differentiated, and 1 was indeterminate. A total of 32-73 mCi I-125 was implanted (median: 47 mCi). The prescribed minimum prostatic dose was 140-160 Gy, and the actual matched peripheral dose ranged from 109-258 Gy (median: 160 Gy). Lymph node dissection or postimplantation prostatic biopsies were not routinely performed. RESULTS Of 54 patients with an elevated PSA prior to implantation and no prior hormonal treatment, 96% returned to normal within 24 months of treatment. In 85% of patients, the PSA fell below 2.0 ng/mL and in 74% of patients, the PSA value fell to below 1.0 ng/mL. Seven patients had disease progression, one of whom has an isolated, rising PSA. The actuarial rate of chemical (rising PSA) or clinical failure at 3 years following implantation was 17%. Of 38 patients who were sexually potent prior to implantation, 81% remained potent at 3 years. Five patients developed radiation-induced rectal ulcerations, 11-22 months following implantation. Three patients required a transurethral resection of the prostate for postimplant urinary symptoms. CONCLUSIONS The short-term clinical and chemical freedom-from-progression rates following I-125 implantation are comparable to that achieved with prostatectomy, with high preservation of sexual potency and moderate morbidity.

CT-based optimized planning for transperineal prostate implant with customized template

A computerized planning procedure has been developed for CT-guided transperineal prostate implants. The segment for custom planning of perineal needle orientations allows placement of I-125 seeds in the entire prostate gland while avoiding the pubic bones. Least-squares optimization (LSO) is used to obtain the seed-loading pattern along the needles. The optimized seed distribution produces a better fit between treatment and target volumes than that obtained from our previous manual technique. Also, the present semi-automatic technique reduces planning time by about a factor of 10 compared to that of the manual approach.

Short-term morbidity from CT-planned transperineal I-125 prostate implants

PURPOSE To summarize short-term morbidity and tumor response following transperineal CT-guided I-125 prostate implantation. METHODS AND MATERIALS Twenty-one patients were treated with CT-based transperineal I-125 prostate implantation between June, 1988 and May, 1990. An average of 75 I-125 seeds were placed, with an average activity of .62 mCi/seed. Symptoms were quantified after interviewing each patient in detail. RESULTS Nearly all patients developed substantial dysuria, nocturia and frequency from 2-24 weeks following implantation. Urinary symptoms usually resolved within 4-6 months of implantation. The one year actuarial potency rate among 18 patients who were potent prior to implantation was 94%. By 6 months after implantation, 14/17 patients (82%) with Stage B tumors had complete regression of palpable disease. Of 17 patients with Stage A or B tumors who presented with an elevated PSA, 76% returned to the normal range within 6 months of implantation. CONCLUSION CT-guided transperineal prostate implants entail moderate, temporary urinary and rectral morbidity. Short-term tumor responses are encouraging.

Fluoroscopic visualization of the prostatc urethra to guide transperineal prostate implantation

PURPOSE To describe a novel way to assure proper needle positioning within the prostate during transperineal implantation, using the urethra as the primary radiographic landmark. METHODS AND MATERIALS Preoperative computerized tomography (CT) images through the prostate are used to plan optimal transperineal needle-seed placement. When performing the procedure, a Foley catheter, with radio-opaque wire is used to visualize the prostatic urethra fluoroscopically in anterior-posterior and lateral projections. Proper needle placement is determined by their position relative to the urethra. RESULTS Sixty patients have been implanted with this method at Memorial Sloan-Kettering Cancer Center from 1990-1992. CONCLUSION The method described here is an improvement over previously described CT-based techniques. It could be used to supplement or replace ultrasound imaging.

Experimental and Monte Carlo dosimetry of the Henschke applicator for high dose-rate 192Ir remote afterloading

We have performed extensive computational and experimental dosimetry of the Henschke applicator with respect to high dose-rate 192Ir brachytherapy using a GAMMAMED remote afterloader. Our goal was to generate clinically useful two- and three-dimensional look-up tables. Dose measurements of the Henschke applicator involved using TLD chips placed in a polystyrene phantom. Monte Carlo simulations were performed using the MCNP code. The computational models included the detailed geometry of 192Ir source, tandem tube, and shielded ovoid. The measured dose rates were corrected for the dependence of TLD sensitivity on the distance of measurement points from the source. Transit dose delivered during source extension to and retraction from a given dwell position was estimated by Monte Carlo simulations, and a correction was applied to the experimental values. For the applicator tandem, the ratio of dose rates obtained by MCNP to those measured by TLD chips ranges from 0.92 to 1.10 with an average of 0.98 and a standard deviation of 0.02. The measured and calculated dose rates at 1 cm on the transverse axis are 1.10 cGy U-1 h-1. For the shielded ovoid, the ratio ranges from 0.88 to 1.16 with an average of 1.00 and a standard deviation of 0.07. Causes of the discrepancy between the Monte Carlo and TLD results were identified. We found that the combined uncertainty of measured dose rates due to these causes is 5.6% for the applicator tandem and 8.4% for the shielded ovoid. Therefore, the results of the Monte Carlo simulation are considered to have been validated by the measurements within the uncertainty involved in the calculation and measurements.

Low risk of perioperative infection without prophylactic antibiotics for transperineal prostate brachytherapy

PURPOSE To determine the incidence of postimplant infection in patients who are not given prophylactic antibiotics (ATBs). METHODS AND MATERIALS One hundred thirty-one patients had computerized tomography (CT)-planned transperineal 125I implantation of the prostate from 1988 through 1995. One hundred fourteen of the patients did not receive prophylactic ATBs, 19 of whom required postimplant Foley catheter drainage for 1 day or more for acute urinary retention. RESULTS The incidence of postimplant febrile episodes within 2 weeks of surgery among the patients who had not received prophylactic ATBs was 2 of 114 (2%). One of the two patients who developed postimplantation febrile episodes was treated successfully with ATBs as an outpatient. The second patient, who had a history of chronic lymphocytic leukemia (CLL) and immune suppression, developed E. coli sepsis and required intravenous antibiotics. Of 17 patients who received prophylactic ATBs, none had a postoperative febrile episode. CONCLUSION We continue to refrain from routinely prescribing prophylactic ATBs unless there is some compelling circumstance including rheumatic heart disease, prosthetic devices, immune compromise, or a previous history of prostatitis.