Racial difference in pre-radiation PSA level for stage T1c prostate cancer

PURPOSE: A three--dimensional stereotactic transischiorectal space CT-guided approach fi~r brachythcrapy is presented to treat patients with localized prostate adenocarcinoma including those with large prostatic volumes (> 60cmJ).while avoiding radiation toxicity to the rectum.METHODS AND MATERIALS: During the past three years, the 3-D steretaactie CT-guided transisehiorectal approach fi)r brachytherapy was perl0rmed on 130 patients with prostatic volumes of 60 cc or greater.Prostatic wdume as calculated by CT and MRI prior to treatment ranged from 60-180 co, with mean of 81 cc and a median of 76 co.Patients were 49 to 90 years with a median age of 71 and with clinical stage TI,T2 and T3,N0.Mx ~¢nocarcinoma.Initial PSA profile was as fi)llows: range, 1.9-48 ng/ml; mean, 14.2 ng/ml, and 10.1 median ng/ml.Fifteen percent of patients had signs and symptoms of urinary obstruction.Thirty percent had Gleason's score of 7 or greater and 52% had PSA of 10 or greater.Planning is performed by CT with a 10 mm electronic grid superimposed over the CT images.Placement of Afterloading needles 5-10 mm outside the capsule of the prostate provides good coverage of the periprostatic tissue and increases the peripheral dose.This is possible because the pubic arch does not interfere with the posterior insertion of the needles through the isehiorectal fat space.Additionally, with the CTguided posterior approach the needles can be placed accurately lateral to the rectum, urethra and more importantly lateral to the prostatic capsule even when gland sizes exceed 60 cm 3.The posterior and vertical insertion of the needles pushes the prostate away from the rectum and results in a separation of the midportion and base of prostate from the rectum by approximately 10-20 mm, minimizing seed placement in the rectum.This separation is not possible by the transperineal approach or by any external beam technique.The peripheral dose is 12,000 cGy for pcl-103 seeds and 16,000 for 1-125.Radiation to the rectum is a least 50% less than the dose delivered under the combined method with brachytherapy and external radiation bean.Insertion of the needles through the ischiorectal fat minimizes bleeding.No patients had hormone manipulation more than 3 months after implant.RESULTS: PSA levels decreased to less than 2 ng/ml in 92% of patients, including those at high risk, measured 6-36 months after implant and to less than 1 ng/ml in 85%.Prostatic volume decreased by an average 50% in all patients.Patients with obstructive uropathy showed significant clinical improvement.Patients had no complications other than treatment-related transient symptoms of urethritis and proctitis.CONCLUSION: The transischiorcctal space CT-guided approach is not limited by prostate size or urinary obstruction.Furthermore, the likelihood of seed placement in the urethra, rectum, or urinary bladder is diminished.No cystoscopy is necessary after the procedure because no seeds are placed in the empty urinary bladder.