Increased prostate cancer screening has led to overtreatment and has not significantly reduced mortality rates in prostate cancer
E. David Crawford, MD, professor of Surgery, Urology, and Radiation Oncology and head of Urologic Oncology at the University of Colorado Health Sciences Center, Denver, was one of the earliest proponents of prostate cancer screening. He even started Prostate Cancer Awareness Week, a tremendously successful prostate cancer—screening program.
Although he still supports it, Crawford now says that increased prostate cancer screening has led to overtreatment and has not significantly reduced mortality rates in prostate cancer. At the 2011 Interdisciplinary Prostate Cancer Congress (IPCC), Crawford discussed alternative approaches that might reduce the overtreatment of prostate cancer.
“PSA-screening has led to increased rates of detection of lower-stage, small-volume cancers. We know that many of these will not progress over time,” Crawford said. Active surveillance has become a popular discussion point in treatment of these patients; however, the approach is not very popular among patients or physicians.
“We give a lot of lip service to surveillance, but when we look at the data from 1990 to the present, what we see is that the number of men undergoing surveillance has not changed,” Crawford said. He explained that it is difficult to convince patients to consider active surveillance. “Once the diagnosis is made, the train has left the station,” Crawford said. “People choose the treatment, and they want it done yesterday.”
The advance toward personalized therapy in cancer has been built on the discovery of molecular markers. Biomarker tests can help identify patients whose cancer is likely to progress, ensuring the right population is being treated. “These new tests for prostate cancer might bring more certainty,” Crawford said, specifically referring to the prostate cancer antigen 3 (PCA3) test.
The test examines the urine for elevated levels of the PCA3 gene, which is overexpressed in prostate cancer. Crawford said the PCA3 test would complement the PSA test by addressing some of the PSA’s shortcomings. “When the PSA identifies somebody with prostate cancer, it doesn’t tell you what kind of cancer it is—is it an aggressive one or a slow-growing one?” The PCA3 test addresses this issue because it correlates with the quantity and aggressiveness of the cancer in the prostate.
Some men with localized prostate cancer are candidates for focal therapy, a treatment that serves as an alternative to radical prostatectomy or active surveillance. This therapy ablates only the cancer site and spares normal tissue, potentially reducing side effects such as erectile dysfunction and incontinence. Ablation can be done with cryotherapy, focal radiation, high-intensity focused ultrasound, brachytherapy, or ethanol injection. This approach is sometimes referred to as the “male lumpectomy.”
Where Are We Headed?
Crawford maintains that biomarkers and targeted therapies are strategies worth pursuing; however, he said better imaging techniques are needed to maximize the efficacy of these approaches. Until that technology is developed and refined, Crawford stressed that the Gleason score* remains the most effective way to assess prostate cancer.
* The Gleason score is one determinant of a patient’s specific risk of dying from prostate cancer and thus strongly influences decisions about options for therapy.