The Big Idea: How a liquid biopsy changes cancer treatment

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One of the many fears that cancer patients face are diagnostics, especially when so many other reasons to fear this disease are present, you would think that diagnostics was relegated to a small area that has to be done mundanely. However once the diagnostic process is a biopsy of cancer and depending on the cancer type, this can be an invasive process requiring a surgeon to perform the biopsy.

In the last, three to four years liquid biopsies have become a mainstay for cancer diagnosis. A stated in a medical article published in the Annals of Translational Medicine: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4356857/ “Certain fragments of DNA shed by tumors into the bloodstream can potentially be used to non-invasively screen for early-stage cancers, monitor responses to treatment and help explain why some cancers are resistant to therapies. For most tumors, a tissue biopsy is quite challenging in that it is costly, painful, or potentially risky for the patient. All these are good reasons to learn about cancer through blood and to get excited about the possibility of carrying out liquid biopsies. The development of non-invasive methods to detect and monitor tumors continues to be a major challenge in oncology.”

 

Alex Sarmiento, a cancer patient, aged 77 now has a better opinion of his future due to liquid biopsies. Alex diagnosed with prostate cancer three years ago; his disease is metastatic and spread nodules around the body. Alex’s wife Dr. Ida Tiongco, a dermatologist from NY asked Alex’s oncologist if she should retire since she wanted to spend the rest of his time together.

Alex’s condition was stable, however, in April his condition deteriorated after the couple made a family visit to the Philippines and his condition worsened. Alex said he thought the jet lag was the reason why he was so weak and exhausted.

Alex was hospitalized twice, receiving debilitating courses of chemotherapy, and Ida stated that where a patient has cancer, there is no relief, neither for the sufferer or their family. Dr. David Nanus, New York Presbyterian hospital’s Chief of Hematology and Medical Oncology, decided to take a liquid biopsy. This is only a diagnostic test, not a treatment. Dr. Scott Tagawa, a New York Presbyterian oncologist, stated that when someone develops cancer, a metastasis one then the individual cells from the tumor break off and flow through the blood stream landing elsewhere in the body, as well as just breaking off and landing in other parts of the bodies cavities. We are interested in the cells in the bloodstream, and all we need to do is take blood as if we were performing a standard blood test. The new test is not as invasive as standard biopsy procedures, and a nurse draws blood as a routine process.

The NCI, National Cancer Institute, defines Liquid Biopsies in their site: https://www.cancer.gov/publications/dictionaries/cancer-terms?cdrid=779095 “A test was done on a sample of blood to look for cancer cells from a tumor that are circulating in the blood or for pieces of DNA from tumor cells that are in the blood. A liquid biopsy may be used to help find cancer at an early stage. It may also be used to help plan treatment or to find out how well treatment is working or if the cancer has come back. Being able to take multiple samples of blood over time may also help doctors understand what kind of molecular changes are taking place in a tumor.”

The blood is taken for analysis in a special machine called a CellCelector, where the lab technician can isolate the cancer cells in the blood and determine what kind of tumor it is, the DNA of the tumor as well as any genetic variances which react differently to different treatments. Within weeks of receiving the results from the test it was observed that Alex had a certain kind of genetic mutation that was resistant to the treatment he was being given, so they changed the treatment and Alex started to recover. Some genetic mutations include BRCA1, BRCA2, and HOXB13.

The main difference from using the liquid biopsy to the standard was the quality of the biopsy. Some biopsies can be successful, others less, due to the nature of taking a piece of tumor cell material. With a liquid biopsy, you get a 100% finding every time.