The dirty little secret that is kept from most of us when we receive primary treatment for prostate cancer is that there is a recurrence rate approaching 33%. This amazingly high rate is consistent no matter what primary treatment is elected. Radiation, surgery, HIFU the rates are the same, about 1/3 of us will experience a prostate cancer recurrence! Given this fact it is easy to understand the constant fear we live under when we finally understand the odds of having a recurrence.
In the situation where we do have a recurrence the fear levels are notched even higher if we are unable to identify where the cancer is located because our scanning technology is not sensitive enough to “see” the tumors. Not seeing them does not mean that they are not there. In some situations, early detection of where the cancer is growing can be critical to our chance of beating it on a second round. If we can’t “see” it we can’t treat it.
Scanning technology has made great leaps in the last two to three years. MRIs are stronger and contrasts are better at disclosing the hidden cancer tumors that can characterize a prostate cancer recurrence. At the Mayo Clinic they have developed a new scan contrast that is specific to detecting prostate cancer, including the tumors that are yet too small to be seen by traditional methods.
Prostate cancer uses choline, a B-complex vitamin, as a building block. When a minute amount of radioactively labeled choline (choline C-11) is injected into a man with a rising PSA, it is quickly taken up by the cancer tumors, including the “hidden” cancer tumors.
These prostate cancer tumors then emit radiation from the label, allowing doctors to pinpoint the tumors exact location(s) using a positron emission tomography (PET) scanner.
According to the experts, this Choline C-11 isn’t toxic and the radioactive element is so minimal, it’s does not much a pharmacologic safety issue. The half-life of choline C-11 is just 20 minutes, meaning it loses half of its radioactivity every 20 minutes.
Because the half-life of the radiation is so short (one factor contributing to its safety) the PET scan contrast material must be used immediately after it is made. This prohibits it from being made off site, shipped to a remote location or stored. So, it must be made on site and used immediately.
The scan itself takes very little time. The making of the contrast takes about 45 minutes and the scan itself takes only about 20 minutes. The results are quickly analyzed and a report is typically ready half an hour after the scan is completed.
A PET scan using choline C-11 makes early tumors highly visible compared to traditional imaging. “For the first time ever, we will have a clear blueprint of where the patient stands, at a far earlier course in treatment failure,” says Eugene Kwon, M.D., a Mayo Clinic urologist. “It has basically ripped the curtain off the Wizard of Oz.”
At this time, Mayo Clinic is the only health care provider in the country that has been authorized by the FDA to do this test. But when filing with the FDA, Mayo Clinic waived all exclusivity. It wanted other sites in the country to be able to manufacture and use the drug to better serve their own patients.
This new contrast is only one of many new ones in use and in trials. It offers us the possibility to take another shot at the cancer post primary treatment.
My hat goes off to the Mayo Clinic because of their concern for people over profits. Cancer treatment should be a concern for all people; we are responsible to care for each other despite profit motivations. We are here to make the world a better place, to heal the world and the Mayo Clinic’s actions acts on this principle.
Joel T. Nowak, M.A., M.S.W.