Imaging Prostate Cancer
Posted: Nov 01, 2018
POSTED: May 30, 2017
On Thursday, our June issue on prevention and screening debuts.
Dr. Snuffy Myers says:
In June, we’re talking about screening and stratifying patients after an initial prostate cancer diagnosis. Why? Most of you have already been diagnosed with prostate cancer: that’s why you’re reading this. All of you are in contact with men in your families and communities who desperately need the information that follows. Share it with them.
Several of our conversations focus on controversies surrounding prostate cancer screening. I have long been highly critical of the US Preventive Services Task Force’s (USPSTF) former, and now revised, recommendations. I object to more than their specific recommendations for prostate cancer: I believe the Task Force’s decision-making process is fatally flawed. I also think that the organization is sufficiently insular that it cannot be reformed. The only effective solution is to replace it with a task force that has a sounder basis in both biology and statistics.
How can we effectively diagnose and treat prostate cancer? We need three steps for screening to favorably impact survival.
The first step is to diagnose. As readers of Prostatepedia know, advances in prostate cancer imaging, such as the fusing of MRI imaging with ultrasound, now allow us to locate and biopsy aggressive cancers.
In a conversation this month, Dr. E. David Crawford reviews the molecular markers that allow us to better identify patients likely to harbor prostate cancers that need treatment while stratifying those that don’t.
After a man has been diagnosed with prostate cancer, the second step is to determine the risk the cancer poses to him, as this determines the appropriate treatment. Traditionally, this risk stratification was done using nomograms like the Partin tables or the Prostate Health Index. Our understanding of the molecular changes that determine prostate cancer aggressiveness has advanced rapidly. We now have tests such as the Oncotype DX, Prolaris, and Decipher that improve our ability to predict disease aggressiveness.
The third step after diagnosis is to offer therapy based on the threat posed by a man’s cancer. One benefit of determining risk based on molecular biomarkers is that we can also better identify patients appropriate for active surveillance. This directly addresses the problem of overtreatment.
As a medical oncologist, I have been concerned with finding the best management for men with the most aggressive forms of prostate cancer. There are multiple well-done randomized trials that show improved survival in men with high-risk prostate cancer if they are treated appropriately while the cancer is still organ-confined.
Without screening, we are much more likely to diagnose the high-risk patient only after his cancer has become metastatic. The USPSTF effectively chose to ignore the fate of these patients, condemning them to early death. This is especially hard to accept because the Task Force had this evidence on hand at the time they gave screening the original D- rating and has not adequately revised those recommendations.