Monotherapy For Early Stage Prostate Cancer Research Articles

Relapse patterns after low-dose-rate prostate brachytherapy

PurposeWhen biochemical failure (BF) develops after low-dose-rate prostate brachytherapy, the relapse site is frequently not found. We set out to find whether prostate-specific membrane antigen positron emission tomography -CT (PSMA PET-CT) scanning has improved knowledge of relapse patterns. Methods and MaterialsA database was analyzed, which contained information and long-term followup on 903 men who had an iodine-125 seed implant as monotherapy for early-stage prostate cancer. There was a total of 68 BFs. ResultIn 38 men developing BF before PSMA PET-CT scanning was available, the site of relapse was local in six, distant in twelve, and unknown in twenty. In 30 men developing BF more recently who had a PSMA PET-CT scan, the relapse site was demonstrated in all cases, and 19 (63%) men had relapsed at the prostate base. Radiation dosimetry of base relapses and paired controls demonstrated that implants routinely delivered a lower radiation dose to the base than to the rest of the prostate. Eight of seventeen cases found to have prostate relapse only underwent salvage prostatectomy. ConclusionPSMA PET-CT scanning is highly effective in demonstrating the relapse site(s) when BF develops after low-dose-rate prostate brachytherapy. Knowledge of the relapse site increases management options for men developing BF.

Single-fraction brachytherapy as monotherapy for early-stage prostate cancer: The UCSF experience

PurposeHigh-dose-rate (HDR) brachytherapy as monotherapy is an effective treatment option for localized prostate cancer, but experience with single-fraction brachytherapy is limited by studies with small sample size. We report a large single-institution experience with single-fraction HDR brachytherapy as monotherapy for early-stage prostate cancer. Methods and MaterialsRetrospective chart review was performed for men treated with HDR brachytherapy as monotherapy for low- to intermediate-risk prostate cancer. Competing risk analyses were performed to estimate subdistribution hazard ratio and cumulative incidence of biochemical recurrence (BCR) and prostate cancer–specific mortality. ResultsWe identified 124 men with a median followup of 2.2 years (interquartile range 25th to 75th percentile: 1.8–3). Overall, 21.0% of patients (n = 26) were low risk, 44.4% (n = 55) were favorable intermediate risk, and 34.7% (n = 43) were unfavorable intermediate risk. At 2 years, the cumulative incidence of BCR was 3.5%: 0% for low risk, 4.0% for favorable intermediate risk patients, and 4.5% for unfavorable intermediate risk patients. In total, 12 BCRs were observed (9.7%) and approximately half occurred after median followup of 2.2 years. Compared with low-risk and favorable intermediate-risk disease, unfavorable intermediate-risk disease was significantly associated with BCR (subdistribution hazard ratio: 3.6, 95% CI: 1.1 to 11.1, p = 0.03). Prostate cancer–specific mortality was 0%. No patient experienced Grade 3 or higher acute or late genitourinary toxicity. ConclusionsSingle-fraction brachytherapy for early-stage prostate cancer was safe with promising short-term disease control rates, especially for low-risk patients. Longer term followup is needed as we observed an overall BCR rate of 9.7%.

Interstitial High Dose Rate (HDR) Brachytherapy as Monotherapy for Early-stage Prostate Cancer: Median 8 Year Results in 321 Patients

Transrectal ultrasound (TRUS)-guided interstitial implant for prostate cancer using low dose rate (LDR) and high dose rate (HDR) technique has been reported with results comparing favorably to surgery and external beam radiation therapy (EBRT). Often, HDR and LDR interstitial implant is combined with EBRT. There is little published data on HDR alone. We report our results with HDR alone. Between 1997 and 2010, 321 patients with T1 and T2 localized prostate underwent TRUS guided interstitial implant, under spinal anesthetic or local anesthetic. There were no Gleason Score or PSA exclusions. No patient received EBRT or hormonal blockade. Median Gleason Score was 7 (range, 4 – 10). Median PSA was 9.3 (2.7 – 39.8). Treatment volumes ranged from 32 cm3 – 196 cm3. Treatment volume included the prostate and seminal vesicles in all cases. Radiation treatment planning was performed using CT scanning and the Nucletron Plato Treatment Planning System. Our IRB protocol for HDR alone, has called for two HDR Implants, spaced 4 weeks apart. The treatment volume received 2250 cGy in 3 fractions prescribed to the 100% Isodose line, given over 24 hours. A second implant was performed 4 weeks later, delivering a further 2250 cGy in 3 fractions, bringing the final dose to the prostate to 4500 cGy in 6 fractions. Urethral dose points (12 – 16) were followed, and limited to ≤105% of the prescription dose. With a median follow-up of 102 months (range, 6 months – 176 months), PSA disease-free survival was 88.8% (285/321). Actuarial 8 year PSA disease-free survival was 86%. The actuarial 8 year PSA disease-free survivals by risk group, were 94% for low-risk, 86% for intermediate-risk, and 65% for high-risk. The procedure was well tolerated, with all patients having completed the procedure. Acute and chronic complications were uncommon. Acute urinary retention occurred in 5.3% (17/321) of the patients, requiring temporary insertion of an indwelling Foley catheter. Urethral stricture requiring dilatation has developed in 5.9% (19/321) of patients. Urinary stress incontinence has occurred in 2.8% (9/321). RTOG late bladder toxicities were: 0% Grade 4, 0% Grade 3, and 2.8% (9/321) Grade 2. RTOG late rectal toxicities were: 0.6% (2/321) Grade 4, 0% Grade 3, 0.9% (3/321) Grade 2, and 1.2% (4/321) Grade 1. Eight-year results with HDR implant alone compare favorably to EBRT, LDR +/- EBRT, and HDR + EBRT, both with regard to PSA disease-free survival, and complications. HDR offers other advantages over LDR, such as no radiation exposure to hospital personnel, no seed migration, greater dose flexibility and precision of radiation dose delivery. Larger volumes can be treated with HDR. By omitting EBRT, bladder and rectal complications appear to be significantly reduced.

10-year biochemical (prostate-specific antigen) control of prostate cancer with 125I brachytherapy

Purpose: To report 10-year biochemical (prostate-specific antigen [PSA]) outcomes for patients treated with 125I brachytherapy as monotherapy for early-stage prostate cancer. Methods and Materials: One hundred and twenty-five consecutively treated patients, with clinical Stage T1-T2b prostate cancer were treated with 125I brachytherapy as monotherapy, and followed with PSA determinations. Kaplan-Meier estimates of PSA progression-free survival (PFS), on the basis of a two consecutive elevations of PSA, were calculated. Aggregate PSA response by time interval was assessed. Comparisons were made to an earlier-treated cohort. Results: The overall PSA PFS rate achieved at 10 years was 87% for low-risk patients (PSA < 10, Gleason Sum 2–6, T1-T2b). Of 59 patients (47%) followed beyond 7 years, 51 (86%) had serum PSAs less than 0.5 ng/mL; 48 (81%) had serum PSAs less than 0.2 ng/mL. Failures were local, 3.0%; distant, 3.0%. No patients have died of prostate carcinoma. The proportion of patients with a PSA ≤ 0.2 ng/mL continued to increase until at least 7–8 years posttherapy. A plot of PSA PFS against the proportion of patients achieving serum PSA of less than 0.2 ng/mL suggests a convergence of these two endpoints at 10 years. Patients treated in the era of this study (1988–1990) experienced a statistically improved PFS compared with an earlier era (1986–1987). This difference appears independent of patient selection, suggesting that the maturation of the technique resulted in improved biochemical control. Conclusion: With modern technique, monotherapy with 125I achieves a high rate (87%) of biochemical and clinical control in patients with low-risk disease at 10 years. The decline of PSA following brachytherapy with low-dose-rate isotopes can be protracted. Absolute PSA and PFS curves merge, and are comparable at 10 years.