Dr. Kevin Most: Blood tests identifying cancer
The cancer blood test study is pretty exciting, the Nassar story is big enough that we should touch on the patient doctor parent relationship.
We could keep the artificial kidney and pancreas until next week. It is at the end of this but we could easily wait until next week for that and just cover Nassar and the Hopkins Blood test. Afraid if we try to cover all of this, nothing gets covered well.
Thoughts?? May tweak it a bit this afternoon.
We always discuss the importance of cancer screening and the fact that for many cancers early detection is the key to long term survival as well to be able to treat with less invasive and toxic treatment. We have also discussed that some cancers we just don’t find soon enough because our screening is off, or we don’t have symptoms until it is too late.
Very exciting news was reported last Thursday in the highly respected Journal “Science” discusses the work on a new blood test that would identify 8 different cancers with a single blood draw. We have discussed the concept in the past, the idea of a liquid biopsy. The hassle, cost and pain of many individual cancer screens may in the near future be replaced by a simple blood test.
If we told women they could have a mammogram or a blood test as a screening, or if we told individuals that a blood test may replace the screening colonoscopy, the patients would line up for the blood test, our compliance for screening would rise and we would find many cancers perhaps years if not decades earlier. We have just not had that option and always thought of it more like The Jetsons
What if I said that this concept of a blood test for a cancer screen is much closer than we have ever thought.
Now, I am not saying that the mammogram and colonoscopy would go away, but they would be used as the second line of screening. Those exams would be completed after a positive blood test was found. Those tools would then be used to identify the location of the cancer, and perhaps treatment of the cancer, they would not be used as a screen to identify if cancer was present.
This test is not ready for total public use but some very encouraging news was released last week. The study is called CancerSEEK, it is based on 30 years of data and is focusing on 8 types of cancer. The cancers it is focusing on currently are ovarian, liver, stomach, pancreas, esophagus, colon, lung and breast. When we look at this list a few jump out as very important.
Lung cancer still a leading cause of cancer deaths, and unfortunately even with recent changes in screening it is often caught too late to make an impact in an individual’s life. Ovarian cancer and Pancreatic cancer are 2 others that often when identified the cancer has spread and treatment options are limited. So, early diagnosis of those cancers can be life changing.
Two others Colon and Breast, we are well aware of and have extensive screening in place to early identify and treat. However, we know individuals often put off the screening tests as well as the stories of those who develop the disease before the acceptable screening is even recommended.
So, the impact of this test would be a game changer as those cancers are responsible for the majority of cancer deaths in the US
The study based at Johns Hopkins is looking at blood samples and identifying genetic material that is shed by tumors. We know what genetic material to look for, now it is being able to find it floating in the blood at levels that are identifiable. So, the study has taken blood for over 1,000 individuals who were already known to have cancer and then tested their blood looking for this genetic material. In other words, they are using patients who we expect to find the genetic material and then looking for it. This is an important foundation as they then took it to the next step, doing the test on 800 individuals who are not known to have the disease, a true screening test. Now, this is not available to the public yet but is expected to be within 1-2 years
So, what did they report, the have been able to show that this blood test was able to accurately detect cancer when it existed in 70 percent of the cases. Probably more importantly it accurately did not detect cancer 99% of the time. The results also gave doctors clues as to where to look for a tumor in 83% of the cases.
The test is more effective in finding some cancers better than others. It was able to identify ovarian cancer 98% of the time, but was only successful in identifying breast cancer a third of the time. Now many will say this is not accurate enough and researchers agree but they are working to perfect the test. More importantly it is giving a screening test to 5 cancers we don’t have screening test for. A simple example, pancreatic cancer, the 5-life survival rate following a diagnosis of pancreatic cancer is around 10 percent and has been there for a long time, individuals who live beyond that, often had their cancer found very early while the doctor was looking for something else, an inadvertent finding, that often is a life saver
Another goal is to minimize the “false positive result” this is when you get a result that says you have disease when in fact you don’t and balance that with not identifying a cancer when it is there or “false negative result” The results thus far should a very low false positive rate.
The goal is to also be able to identify cancer early on, not just its presence but early in its presentation.
So, what is going on, the study is looking to expand to a much larger portion of the general population, healthy individuals and start seeing how accurate it is and how early it can detect disease. This portion of the study has been expanded to 10,000 individuals who will be tracked for five years.
This study is so encouraging that many expect to see this out within a year or two and with a cost close to $500. One would expect that over the next 2 years researchers would be able make the test more sensitive, finding disease earlier as well as more specific, true results.