In the past few years, urologists have seen some significant developments related to the treatment of metastatic castration-resistant prostate cancer (CRPC).
Sipuleucel-T, a therapeutic cellular immunotherapy, was approved by the FDA in April 2010 after clinical trials showed that it prolonged survival by a median of four months in patients with asymptomatic and minimally symptomatic CRPC.
In November 2010, the FDA approved the biologic denosumab for preventing skeletal-related events in patients with bone metastases from solid tumors. In April 2011, the FDA granted marketing clearance for abiraterone acetate in combination with prednisone as a treatment for patients with metastatic CRPC who have received prior docetaxel-based chemotherapy.
In phase 3 trials, the treatment prolonged overall survival by a median of 3.6 months. Other promising treatments for this patient population are in the pipeline, as well. At the recent annual meeting of the American Urological Association, researchers presented data showing that enzalutamide (formerly MDV3100) improved median overall survival by nearly five months.
Updated findings presented at the American Society of Clinical Oncology showed that an investigational bone-targeting agent called radium-223 prolonged median overall survival by 3.6 months with minimal toxicity. The growing list of treatments for CRPC could give researchers more to work with in designing new therapeutic paradigms for CRPC, such as using the drugs in combination or earlier in the disease process. (E. David Crawford, MD, head of urologic oncology at the University of Colorado Hospital in Aurora, discusses the possibilities in an interview on page 25.) It also should be cause for greater optimism among CRPC patients, who may now have good reason to look forward to living longer than in the past.
Although urologists will no doubt be pleased by the growing armamentarium for treating CRPC, they may be dismayed by the recently released final recommendations from the U.S. Preventive Service Task Force calling for an end to routine PSA-based mass screening for PCa (see the article on page 17). The task force concluded that the benefits of screening do not outweigh the risk, while acknowledging that “clinical decisions involve more considerations than evidence alone.”
How much weight these recommendations will carry is questionable, however. Recent studies suggest that 2008 task force recommendations against PSA screening of men aged 75 and older has had little or no impact. For example, using data from the 2005 and 2010 National Health Interview Survey, investigators found that PSA tests were ordered for 40.6% of men aged 75 years and older in 2010 compared with 40.4% in 2005.
So, although the task force recommendations have the potential to discourage screening, it is not a given that physicians will follow them.