Should You be Screened for One of the Most Aggressive Human Cancers?

Tuesday, November 11, 2014

Sarah “Betsy” Rodriguez, MD

Patrick Swayze. Michael Landon. Luciano Pavarotti. Randy Pausch, author of The Last Lecture. We remember the names of celebrities who were stricken with cancer of the pancreas and inevitably died within a year or two.

But there is another name out there: Ruth Bader Ginsberg, the Supreme Court Justice who had a routine CT scan as a follow-up for colon cancer she had many years ago. The CT scan showed a small, early-stage pancreatic cancer. She underwent surgery in 2009, and has now passed the 5-year mark, still alive and apparently well. There are screening tests for many cancers—colonoscopy for colon cancer, mammography for breast cancer, blood test and exam for prostate cancer—and you might wonder if you should you have a CT scan or some other test to screen for pancreatic cancer.

The answer lies partly in how at-risk you are for the disease. Pancreatic cancer is in the spotlight because it is so deadly, but it is actually an uncommon malignancy in the general population. In the United States, there are around 47,000 new cases of pancreatic cancer per year, out of the 315 million or so of us in this country. This places cancer of the pancreas at number 10 on the list of cancers, behind lung cancer (approximately 207,000 new cases), breast cancer (222,000 cases), prostate cancer (209,000) and colon cancer (135,000 cases).

Population-wide screening (testing everyone over a certain age) only works if the disease in question is common enough to make screening work, and if there is a good screening test for it. If it is an uncommon disease, you have to screen many, many people to find even one case of cancer, and a positive screening test is much more likely to be falsely positive in this situation (meaning the test is wrong).

Who is at increased risk? 

We know the risk of pancreatic cancer goes up after age 50, and the average age of diagnosis is 71 years old. Like so many other cancers, men are at higher risk than women. About 25-30% of pancreatic cancers are directly related to smoking. Obesity and physical inactivity increase the risk of pancreatic cancer. Alcohol does not appear to directly cause pancreatic cancer, but excessive alcohol CAN cause chronic scarring of the pancreas in some people, which then increases the risk of cancer formation. There is some debate about whether diabetes places you at higher risk; this is not clear from the medical literature. Finally, 5-10% of pancreatic cancers are due to genetics, and we mainly identify these people by their family history.

Who is eligible for screening? 

People who have two first degree family members (parents or sibling) who had pancreatic cancer may be considered for screening, and those with 3 or more family members, at least one of whom was a first-degree relative, are also eligible. There are a few genetic conditions as well that indicate increased risk, including people with hereditary pancreatitis, people with mutations in the BRCA gene (hereditary breast/ovarian cancer, as long as there is also a family history of pancreas cancer), Peutz-Jeghers’ syndrome, and other more rare mutations.

If screening for pancreatic cancer is to be done, how do we do it? 

Unfortunately, there is no blood test that is good enough for screening purposes. There is a blood test called the Ca 19-9 that is elevated in most people with pancreas cancer, but it is not adequate for screening purposes because it can be elevated for other reasons, and about 15% of people don’t have this marker at all. CT scans are not good enough to identify small tumors, and they expose you to unwanted radiation, especially if you are getting screened more than once. MRI is good and is getting better all the time, and has the advantage of not using any radiation. Finally, there is an endoscopy procedure called endoscopic ultrasound, or EUS. This is similar to an upper endoscopy, where a tube with a camera and light are passed down through the mouth (with sedation of course) and the pancreas is examined by looking through the stomach wall. This procedure has the advantage of getting an excellent look at the pancreas, and also if something is seen like a cyst or other abnormality, it can be biopsied at the same time. The disadvantage of EUS is that it requires sedation and the small risks that go along with any endoscopic procedure.

What can you do to lower your risk of pancreatic cancer?

Age over 50 is the biggest risk factor, and no matter how hard we try, we cannot change that! The biggest thing you CAN do is to avoid smoking. If you smoke now, stop. Your risk will remain elevated over a nonsmoker for years to come, but eventually may return to normal levels (which is to say, low risk). You cannot change your family history, but it is important to be aware of it. Finally, if you are very overweight, try to lose weight and get more exercise.

So, should YOU be screened for cancer of the pancreas?

The answer is: probably not, unless you have a family history of more than one relative on the same side of the family with the disease, or one of the genetic conditions mentioned above. If you are a candidate for screening, the usual test is endoscopic ultrasound or MRI, and this is usually once a year. It is important to know that pancreatic cancer screening is something we do not have a lot of information about right now. There are ongoing studies to address this issue, and in the future, we should be able to offer a lot more guidance in this area.

Centers for Disease Control National Program of Cancer Registries (NPCR). Accessed October 15, 2014.