New data from two studies on adjuvant radiation and thalidomide post-surgery

Biochemical recurrence after first-line treatment for localized prostate cancer affects some 30 to 40 percent of prostate cancer patients. Two articles to be published in the March 2009 issue of The Journal of Urology provide interesting new data on the treatment of men who have either failed first-line surgical treatment or are at high risk for such failure.

In a recent, two-phase, double-blind, placebo-controlled multicenter trial, researchers have investigated the addition of thalidomide to intermittent androgen deprivation therapy (ADT) as treatment for progressive disease. Patients were given ADT for 6 months, followed by thalidomide or placebo until their PSA increased (Phase A). In this phase of the trial, the authors found that the median time to PSA increase was 15 months for the thalidomide patients versus 9.6 months for placebo patients. In the second phase of the trial (Phase B), patients were given another 6 months of ADT followed by thalidomide and placebo, but now now switched between the two patient groups. During Phase B, the median time to PSA increase was 17.1 months for thalidomide and 6.6 months for placebo.

Writing in the article, William D. Figg, Medical Oncology Branch of the National Cancer Institute, National Institutes of Health, states, “Thalidomide is associated with an increase in …  progression-free survival in men with biochemically recurrent prostate cancer after intermittent ADT. These effects were independent of any effects on testosterone. This is the first study to our knowledge to demonstrate the effects of thalidomide using intermittent hormonal therapy.” The “New” Prostate Cancer InfoLink would add that thalidomide is also associated with a range of problematic side effects. A similar trial of intermittent ADT in combination with the second-generation agent lenalidomide could potentially demonstrate results that are at least as good with a lower incidence of adverse events.

In another multi-institution study, led by Ian Thompson, MD, of the University of Texas Health Science Center at San Antonio, the researchers were able to show that adjuvant radiotherapy significantly improves survival after radical prostatectomy in patients with advanced prostate cancer. In this study, based on the treatment of 425 men initially diagnosed with high-risk prostate cancer (pT3NoMo), 211 were observed after surgery for signs of recurrence, and 214 received adjuvant radiotherapy shortly after surgery. This trial was originally initiated in 1988. Unlike most studies of this type, which have given results based solely on PSA recurrence, this study’s endpoint was development of metastatic disease.

When data were evaluated in 2008, after an average 12.7 year follow-up, adjuvant radiation therapy was found to reduce the risk of metastases by 29 percent and to improve survival by 28 percent. In addition, the risk of a detectable PSA after surgery (the first evidence of disease recurrence) was reduced by 58 percent and delayed by more than 7 years. The authors found that all risk groups studied appeared to benefit.

Radiation therapy also significantly reduced the need for ADT after surgery. Using measures of quality of life, the study found increases in patients’ urinary and bowel symptoms in the radiotherapy group at 6 weeks and 2 years, but these differences subsequently disappeared.

Dr. Thompson commented that “Adjuvant radiotherapy within 18 weeks after radical prostatectomy in a man with pT3N0M0 prostate cancer significantly reduces the risk of PSA recurrence, metastasis and the need for hormonal therapy, and significantly increases survival. All of the approximate 30,000 men each year that face this condition should be informed of the results of this study.”

[Editorial comment: Links to actual abstracts of these articles were added on February 17, 2009.]

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