Suppose you find yourself experiencing symptoms like fatigue, rapid heartbeat, especially following exercise, dizziness, pale skin, and insomnia. You go to a doctor and your doc asks you to get some tests done- most probably a blood test. You get it done and your readout says that you have low hemoglobin and bingo- you are diagnosed with Anemia. Practically all forms of anemia are treatable and your blood test has served as a ‘window’ into your health problem, for your doctor. Essentially, your physician has had a ‘look’ at your health problem.
If you have abdominal pain, X-rays and ultrasound readouts provide, quite literally, a picture of your health issue.
Chest pain? No problem. An ECG and echocardiogram will provide a picture of your heart health.
Pregnancy? You will have at least three scheduled ultrasound examinations and get to ‘see’ your baby.
Brain issues? An MRI can help your doctor understand what’s wrong. Breathlessness? A lung X-ray will help.
See the pattern here? For most illnesses, there are techniques to visualize your body and understand what’s going on. Images are powerful tools that help your doctors evaluate your condition, accurately. What about cancer? How does one ‘see’ what’s going on in the body, especially after starting treatment? Is the treatment working? What if the cancer comes back and starts growing on some deep organs like liver?
There’s a simple way now to understand how cancer is responding to treatment- Liquid Biopsy!
Liquid biopsy is a simple blood test that allows scientists to check for clues that cancer cells leave behind- namely cancer DNA. Most tumors have a unique pattern of genes that go wrong in them. This is like a tumor fingerprint or a tumor barcode. Now, when we get hold of a tumor biopsy, it’s possible to extract DNA from it and determine this ‘barcode’. How does this help? Once a patient starts therapy, a small amount of blood can be drawn, at desired frequency, and we can check whether the tumor DNA barcode shows up in it, or not.
Skeptics are bound to say, “So what? There are PET-scans to ‘see’ if the cancer spots are back or not.” Er.. true, however, you can perform a PET-scan only once in 6 months, because of exposure to radioactive dyes. On the other hand, liquid biopsy tests are NOT radioactive and can be performed, quite literally, at will. Also, some recent research has shown that DNA evidence provided by liquid biopsies is usually present much AHEAD of development of cancer spots that are visible on a PET-scan.
Last year, Suneet Varma presented with colorectal cancer, in August 2016, and was advised surgery to remove the tumor. Once the tumor was out, a sample was sent to Strand and we determined the genetic ‘barcode’ of his tumor. There was a harmful mutation in the KRAS gene in his tumor; this mutation has been known to cause colorectal cancer. Suneet provided a blood sample just before the surgery. Now, once his tumor barcode was determined, we also tested for the same gene mutation in his blood and found the same in tumor DNA released into the blood.
In December 2016 and in April 2017, Suneet’s doc sent us more blood samples to follow-up on his cancer. In both samples, we did not find tumor DNA. With cancer, you can never be too watchful. Although the earlier results were reassuring, his doctor wanted to be doubly sure that all the cancer has been removed, completely. The last blood sample from Suneet was analysed in August 2017; the good news is that the original tumor barcode was not detected in the latest liquid biopsy.
Taken together, liquid biopsy tests have worked like a ‘Cancer Camera’ or a ‘Cancer Detective’ in Suneet’s case and helped his doctor actually have a ‘look’ into the progress of his cancer therapy.
So, will this work with colorectal cancer only? Nope, these liquid biopsy tests can be developed for other solid cancers as well, so long as we can get hold of a good amount of original solid tumor biopsy.