Prostate Cancer Research:
A Model for Success
Men's Health Week, June 13-19, is a good time to celebrate the tremendous progress we've made against prostate cancer - the second leading cause of cancer death among men after lung cancer. Remarkably, more than 85 percent of all prostate cancer diagnoses now occur before the disease has spread. As a result, the relative 5- and 10-year survival rates for men diagnosed at this stage are 98 and 86 percent, respectively.
But a prostate cancer diagnosis offers a vexing choice for many men, because only 1 in 10 prostate cancers poses a mortal threat. In the absence of symptoms, prostate-specific antigen (PSA) levels and biopsy results yield limited information about how aggressive the disease is. As a result, for many men, whether to undergo treatments such as surgical removal of the entire prostate, radiation, or engage in watchful waiting, is disturbingly ambiguous.
As a prostate cancer survivor and urologic oncologist, I have been greatly encouraged by the research being done to help patients and clinicians make more informed decisions. In most cancers, we are endeavoring to identify biomarkers that will signal the early presence of the disease, but prostate cancer presents the challenge of developing markers that will define the virulence of the disease.
In a study of 400 men with prostate cancer published this month in Cancer Epidemiology, Biomarkers, and Prevention, researchers from the NCI Specialized Program of Research Excellence (SPORE) at Dana-Farber Cancer Institute in Boston showed that low levels of a specific protein, AMACR, may be a powerful biomarker for aggressive disease and may yield some specific data. A 1,300-patient confirmatory study conducted in conjunction with Swedish researchers is already underway.
For those with cancer, numerous treatment advances have been made. Prostate cancer surgery can now be performed less invasively with laparoscopic techniques, and a number of facilities now offer robotic laparoscopic surgery, which may provide additional safety advantages. Radiation therapy also has improved, with new technologies allowing for more precisely targeted radiation, resulting in lower radiation doses.
And potentially new treatments may come in the form of vaccine therapy. Encouraging results have been reported in early clinical trials with a recombinant viral vector-based vaccine containing the genes for PSA and three immunostimulatory molecules developed by NCI. A cooperative group phase III trial is in the late planning stages that would test the vaccine in asymptomatic patients who have been treated with hormone therapy and whose only evidence of prostate cancer is a rising PSA. The trial may be launched later this year.
Prostate cancer research offers a model of how we're attacking cancer in the 21st century: conducting well-designed clinical trials and combining our expanded understanding of this disease's molecular underpinnings with the advantages offered by advanced technologies to improve our diagnostic, prognostic, and treatment armamentarium. We've made tremendous inroads against prostate cancer, and I have high expectations of many more to come.
Dr. Andrew C. von Eschenbach