The co-authors of Invasion of the Prostate Snatchers, blog alternate posts weekly. We invite you to post your comments.

Tuesday, July 1, 2014

Combidex the Detective: Where has the Cancer Spread?


In our book, Invasion of the Prostate Snatchers, Ralph Blum and I devoted a chapter to the heartbreaking story of how Combidex, a revolutionary way to detect cancerous lymph nodes, was shot down by the FDA.  Detecting cancer in the lymph nodes is the Holy Grail of cancer scanning because the lymph nodes are the first place prostate cancer usually spreads if it leaves the prostate.  Standard CT scans fail to detect cancer until the tumorous nodes are bulging with cancer.

The early detection of lymph node metastases has become a much higher priority now that lymph nodes can be safely targeted with modern radiation.  In the past, with older radiation, side effects were excessive due to collateral damage to the intestines.
At Prostate Oncology Specialists we have had reasonably good results imaging lymph nodes with C11 acetate PET scans performed by Dr. Fabio Almeida in Phoenix.  Also, Choline PET scans have been used with success at the Mayo Clinic. However, even with PET scans there needs to be minimum amount of tracer present in the lymph node before it reaches the threshold of detectability. Therefore, PET scans may be unable to detect metastatic nodes until the cancerous nodules are more than 6 mm in diameter.  Studies evaluating intravenous Combidex in conjunction with MRI scanning indicate that normal lymph nodes can be distinguished from metastatic nodes even when the metastases are as small as 3 mm. In one study comparing Combidex with Choline PET scans, Combidex was more accurate at detecting metastatic nodes.
I am raising the matter of Combidex in this blog because now, for the first time in years, Combidex has become commercially available again in Europe.  Dr. Jelle Barentsz from the University in Nijmegen has been able to purchase all rights to Combidex along with all the documents and files from the original manufacturer. Unfortunately, as yet there are no sites in the United States that offer Combidex.
More than 50,000 men annually develop a cancer relapse after surgery or radiation.  A relapse is indicated by the presence of a rising PSA level in the blood. The rising PSA signals that cancer is present, but offers no indication about the location of the cancer in the body. New scans such as C11 PET and Combidex-enhanced MRI have opened up a whole new realm of treatment possibilities. After all, if the cancer can be located, it creates a possibly for cure by targeting it with radiation.
We welcome the renewed availability of Combidex, thanks to the concerted efforts of Dr. Barentsz.


Past Blogs by Ralph Blum

Latest PCRI Insights written by Jelle Barentsz, MD


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