Brachytherapy for prostate cancer

Today, brachytherapy is back, but with a new twist. Instead of requiring an incision in the abdomen so that seeds can be manually injected into the patient’s exposed prostate, the new procedure uses needles to deliver the tiny seeds through the perineum. The seeds’ placement is planned using three-dimensional computer software and performed under the guidance of transrectal ultrasound.

Eliminating the need for invasive surgery is an obvious plus for patients. But more importantly, the new brachytherapy enables physicians to precisely place the seeds—eliminating any clumps or gaps that might allow cancer cells to survive. And that, says Juanita Crook, a radiation oncologist at Toronto’s Princess Margaret Hospital, is the key to the potential effectiveness of the newer procedure.

To determine how effective the new procedure is, Crook reviewed the recent brachytherapy literature (Can. Med. Assoc. J. 2001, 164, 975–981). Yet her review provided no definitive answers. Nor could it. Prostate cancer is typically slow-growing, and the new technique has not existed long enough for doctors to study long-term survival rates. Results up to 10 years using prostate-specific antigen (PSA) and post-treatment biopsies as surrogate end points, however, are promising.

The brachytherapy results were mixed. The absence of cancer (as determined by low PSA levels) was reported in 63–93% of cases 4–5 years after implantation, whereas positive biopsy results were only reported in 3–26% of cases within 2–3 years.

However, those individuals with low-grade tumors do best with the procedure. Unfortunately, the results were not compared with those for prostectomy, the standard treatment for localized prostate cancers.

Regardless, Crook concludes that brachytherapy is a viable option for treatment of prostate cancer—at least for a subset of men with localized disease. “I’m not pushing this above radical prostectomy, but it’s another option that suits a lot of men,” says Crook. “It should be available, and it should be considered.”

In a related commentary (Can. Med. Assoc. J. 2001, 164, 1011–1012), J. Curtis Nickel, a urology professor at Queen’s University in Kingston (ON), agreed that with increased awareness of prostate cancer and regular use of PSA testing, identifying this subset of potential brachytherapy patients will be easier than it was several years ago.