ASTRO: Younger men benefit from prostate brachytherapy

Oct 31, 2007

LOS ANGELES - Age should not be a deterrent for using brachytherapy as a primary treatment mode for young men with prostate cancer, according to a study presented this week at the American Society for Therapeutic Radiology and Oncology (ASTRO). In this analysis, men ages 60 and younger achieved "excellent" five-year biochemical control rates compared to their older counterparts (61 years and older).

"It is a common belief that younger patients tend to have more aggressive disease than those patients who are older," and may only be eligible for surgical treatment, said lead author Dr. Alice Ho. "We conducted a large study of prostate cancer with localized disease."

At the time of the study, Ho was a resident at Mount Sinai Medical Center in New York City. She is currently based at Memorial Sloan-Kettering Cancer Center, also in New York City.

The patient population consisted of 1,763 men with clinically localized prostate cancer who were treated with low-dose-rate brachytherapy, with or without external-beam radiation therapy, as well as hormone therapy between 1990 and 2005. Follow-up was done for at least two years. The men were divided into three age groups: 60 and younger, 61-75, and older than 75.

Univariate and multivariate Cox regression analyses were used to determine if any variable (degree of risk, Gleason score, pretreatment PSA, stage, treatment type) was predictive of five-year biochemical freedom from failure (bFFF).

The results showed that, for the entire patient group, the bFFF was 90%. The univariate analysis determined that younger men demonstrated improved five-year biochemical control rates at 96%, compared to 89% for men age 61-75 and 88% for those 75 and older. On multivariate analysis of the entire group, treatment era (1990-1997 versus 1998-2005) and biologically effective dose (≤ 150 versus >150) were significant in predicting five-year biochemical control.

Ho's group noted that a significant number of young men in the patient cohort had presented with early-stage disease, which is contradictory to the belief that younger men have more aggressive disease. Ho attributed this difference to two shifts in attitudes about prostate cancer.

"With PSA screening, more and more cancers are being picked up at an earlier stage with these (younger) men," Ho explained. "In earlier years, we weren't even seeing young men for consideration of brachytherapy or seed implant. (Now) the urologists are more willing to present this is a treatment option."

Ho said she did not believe that the results of her group's study were biased toward patients with a better prognosis. In the radiation oncology department, "we tended to get patients who actually had worse prognosis because the common belief is that surgery is better," she said. She attributed the success of brachytherapy in this group of men to technological improvements.

"The main reason why the younger patients did well in our study is that ... it's (now) possible to deliver high radiation dose both safety and effectively. As the technology improved, more young men (were) seen in the clinic, wanting (radiation treatment). There's more awareness that seed implantation is available," she said.

During the ASTRO session, Dr. Anthony D'Amico, Ph.D., from the Dana-Farber Cancer Institute in Boston, noted that previous research has shown that men who undergo radiotherapy for prostate cancer have a small risk for second cancers. He asked how Ho would address this risk with young patients who are deciding between surgery and brachytherapy.

"I think whenever you offer radiation to a younger population of patients, the risk of second malignancies is something that needs to be considered very carefully," Ho replied. "These young men who are actually coming for brachytherapy tend to be very savvy, and I think follow-up would be important. Before offering this type of treatment, I would factor in their compliance and their ability to be followed up after treatment."

In a commentary on this study, Dr. Anthony Zeitman of Boston's Harvard Medical School stressed that it was important to give patients a choice. "Traditionally, it's been said that prostate cancer is little bit more aggressive in younger men, and that younger men need more aggressive therapy, which traditionally means surgery," he said. "If that's the case, we can accept that. (But) if that's not the case, then patients are having their choices artificially narrowed."

By Shalmali Pal
AuntMinnie.com staff writer
November 1, 2007

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