Imaging Prostate Cancer
Posted: Nov 01, 2018
POSTED: September 04, 2015
In the October 2014 issue of Prostate Forum, we feature conversations with Dr. Paul Lange of University Of Washington and Dr. Jeffrey Karnes of Mayo Clinic about surgical approaches to prostate cancer spread.
Here’s Dr. Snuffy Myers’s introduction to the issue. If you’d like to read the conversations with Dr. Lange and Dr. Karnes, download the issue. Or better yet, subscribe! That way you won’t miss any of the informative interviews we have lined up for the next year.
Over the past year, we have featured a number of interviews with investigators working at improving prostate cancer imaging. In particular, we focused on better techniques to image prostate cancer that has recurred after radical prostatectomy or radiation therapy. This naturally led to the question of what to do about the metastases we detect with this improved imaging. This is an area of great controversy.
In this issue, we feature conversations with two of the major figures in this area. We lead off with Dr. Paul Lange from the University of Washington in Seattle. As he recounts, he has established one of the foremost prostate cancer research groups in the world. This team has made major contributions to our understanding of prostate cancer biology. The second conversation is with Dr. Jeffrey Karnes from the Mayo Clinic. Dr. Karnes has extensive experience using modern imaging techniques to find metastatic prostate cancer. He has then used surgical approaches to remove those metastatic sites. In coming issues of Prostate Form, we will talk with investigators who have used radiation therapy. By the end of this series, you will be able to compare these different approaches.
Before we proceed, I’d like to out-line the biology behind the controversies in the field. Dr. Lange and his col- league, Dr. Robert Vessella, developed a very sensitive technique to detect prostate cancer cells in the blood of patients about to have a radical prostatectomy. It is important to note that these patients were good candidates for prostatectomy. They found that a large proportion of these men had prostate cancer cells in their blood. They then went further and showed that these men had prostate cancer cells in their bone marrow. Thus, the cancer had already spread widely before surgery. After surgery, the cancer cells disappeared from blood and bone marrow in most patients. The apparent clinical “cure” rates were as you would expect. However, in some patients, the cancer cells could still be found. Those patients were at increased risk for the cancer to return years later. The point was that while cancer cells persisted, the disease could remain clinically invisible for years.
Studies by other groups have documented that prostate cancer could recur more than 20 years after surgery. These results show that prostate cancer spreads widely before surgery in many patients and that this cancer can remain clinically silent for a very long period. This same phenomenon has been shown for many other cancers. The phenomenon is called cancer dormancy. There is a nice short description of cancer dormancy at http://www.wikipedia.org
The second set of observations come from the modern imaging studies done in men with recurrent prostate cancer. These studies have shown that in many men, the recur- rent cancer is often limited to a few spots. The lymph nodes in the pelvis and lower abdomen are the most common sites. Even in men with bone metastases, there are often initially only a few bone sites involved. If this is true, what does it imply? While the cancer may spread widely, in many patients only a small number of these cancer cells become activated and lead to clinically detectable disease.
This sequence of observations led to the concept of oligometastatic cancer. (The prefix “oligo” means few.) If you treat and get rid of the few visible metastatic sites using radiation or surgery, what happens? In some patients, new cancer metastases rapidly appear. In these patients, it is not apparent that they profited from the radiation or surgery.
However, many patients have a pro- longed period free from cancer before it recurs. Some patients remain free of cancer. At AIDP, we have patients free of recurrence for more than ten years. I am one of them and remain free of recurrent cancer more than 15 years after treatment for metastatic prostate cancer.
In this and select subsequent issues of Prostate Forum and videos posted at askdrmyers.wordpress.com, we will be delving deeply into the implications of these observations.
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