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High-Dose Brachytherapy Safe and Effective Prostate Cancer Monotherapy

Caution recommended for positive biopsy cores more than 75 percent

High dose rate brachytherapy as monotherapy is safe and effective for patients with intermediate-risk prostate cancer, according to the results of a study published recently in the Journal of Urology.

There is no single, straightforward treatment for patients with organ-confined prostate cancer. For patients with intermediate-risk prostate cancer, treatment recommendations include radical prostatectomy (RP), electron beam radiotherapy (EBRT) with maximum androgen ablation, EBRT with a brachytherapy boost, and brachytherapy alone. The authors of the current study sought to investigate high dose rate brachytherapy as monotherapy for intermediate-risk prostate cancer.

The researchers followed 284 men with intermediate-risk prostate cancer, defined as T2b/T2c, Gleason score of 7, and/or prostate specific antigen (PSA) of 10 to 20 ng/mL, and one year minimum follow-up. Treatment was two high dose rate brachytherapy procedures at three fractions of 6.5 Gy each for a mean of 19 days. PSA failure was defined as nadir +2 ng/mL. Mean follow-up was 35.1 months. Actuarial five-year survival was 98.8 percent, and biochemical disease-free survival was 94.4 percent. Clinical stage predicted biochemical disease-free survival. For stage T2a or less, five-year biochemical disease-free survival was 95.1 percent, compared to 100 percent for stage T2b and 77.4 for stage T2c. Percent positive biopsy cores and PSA nadir were also predictive. International Prostate Symptom Score results remained stable and potency was maintained in 82.6 percent of patients at two years. Pads were used for the first time after brachytherapy in 7.7 percent of patients, mostly for grade 1 incontinence. Excluding patients with prior transurethral prostatectomy, stroke, or tremor, 2.5 percent used pads for the first time after treatment. No patient had urethral stricture. Radiation Therapy Oncology Group grade 1 rectal toxicity developed in 4.2 percent of patients, but not beyond grade 1.

The authors conclude that with "individualized attention to anatomy, brachytherapy catheter placement and geometry, target dosing and dose constraints, and with pretreatment needle position verification and adjustment HDR-MT is effective and well tolerated."

Source: Rogers CL, Alder SC, Rogers RL, et al. 2012. High dose brachytherapy as monotherapy for intermediate risk prostate cancer. Journal of Urology 187:109-116.