One of the most lethal of all cancers, pancreatic cancer affects over 45,000 Americans annually, almost all of whom will die of the disease. This compares to over 200,000 new cases of lung, prostate and breast cancer, and a slightly smaller number of new cases of colon cancer. Given the high mortality from pancreatic cancer compared to these other cancers its impact on overall cancer mortality is almost as great as breast and colon and higher than prostate cancer. What can be done about this?
For the first time researchers have identified a blood test which can identify patients with very early stage pancreatic cancer. It relies on looking for the presence of extra methyl groups on the genes seen in pancreatic cancer, so called methylation. BNCI1 and ADAMTS1 are both genes which are methylated in pancreatic cancer tissue but not normal tissue. Using new techniques extremely small amounts of this methylated DNA can be found in the bloodstream of people with early stage pancreatic cancer. In the journal Clinical Cancer Research, scientists from Johns Hopkins describe their new methodology in detail. Their ability to discriminate normal people from those harboring early stage pancreatic cancer was close to 100%! If you want the actual article, request it from Dr. Stark by filling out the form on the right of this page. He cannot create a link to the full article because of copyright constraints.
Since pancreatic cancer is a largely a disease of aging, what is keeping this blockbuster observation from becoming part of the usual cancer detection paradigm for adults over age 50, like mammography or colonoscopy? Three things:
Cost: right now this is a research tool. Until a kit is produced and the test can be performed on a large scale for a reasonable price, the test would be prohibitively expensive;
Frequency of the disease: as mentioned above, pancreatic cancer is only about one fifth as prevalent as the diseases for which we have effective screening; however, its lethality could overcome this barrier;
Proof of altered outcome: so few people are operated on for very early stage I pancreatic cancer that no one knows if a very early diagnosis could impact mortality. We do know that you can’t find some cancers early enough. Malignant brain tumors are a perfect example. Someone will have to launch a study to show that people whose cancers are detected by this blood test have a cure rate appreciably greater than zero. So….who should be in this study? Right now we know that patients who harbor mutations producing the BRCA1 and 2 genes and people with familial colon cancer syndromes (FAP and Lynch syndromes) are at much higher risk for pancreatic cancer. Arguably all patients harboring these mutations should be studied with the annual pancreatic cancer blood test to see if the mortality from pancreatic cancer can be lowered to less than its currently abysmally high rate. One could argue that a randomized trial to do this would not be necessary. Since Johns Hopkins is a center for the treatment of pancreatic cancer, one would hope that they will lead the way in this endeavor.
Update 2020: since this original post was created, one could have hoped that a commercial blood test for pancreatic cancer would be developed. Sadly, not so. The current literature still touts the current potential for a test that measures abnormal, tumor-associated DNA in the blood, but no test has been put through the rigors necessary to achieve status as clinically reliable and relevant. The current state of affairs is summarized nicely in a recent review. Click here to view.