Tracking Cancer Through Blood Biopsy

Beginning with Blood Biopsies

An NPR segment recently addressed the bright future of blood biopsies for tracking cancer and determining treatment, without the use of surgical tissue biopsy. Broad Institute of MIT and Harvard is one of the world’s leading centers of genomic research, and they have been working on a project to better understand metastatic breast cancer using blood biopsy technology. Their research population is around 3000 women, and nearly 100 researchers and doctors from the Boston area are participating in the analysis of the blood biopsies. Per NPR’s interview with Dr. Nikhil Wagle, of the Dana-Farber Cancer Institute, there is a “hope [to] ultimately use blood biopsies to guide how he treats patients: first, to decide which drugs to use based on the tumor DNA; and then, with repeated blood tests over time, to see how well the treatments are working.”(1)

Two Companies Currently Offering Blood Biopsies

But NPR may have given a false impression of where current blood biopsy technology exists. Listening to, or reading the transcription gives the impression that Broad Institute is the only cutting-edge lab working on this, and that it’ll be years before clinicians are using this technology for the purposes outlined above. This is simply not true. At least 2 companies are already offering liquid (blood) biopsies, which use similar technology to analyze for circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs): Biocept, and Guardant Health. Both are using next-generation sequencing to analyze DNA shed by cancer cells – ctDNA. In fact, Guardant Health’s Guardant360 liquid biopsy is recognized by the NIH: National Cancer Institute as “highly consistent with gene alteration patterns reported in traditional tumor tissue testing.”(2) The consistency was quantified at between 94 and 98%.(3)

Liquid Biopsies Approved by FDA

In addition, liquid biopsies have recently been approved by the FDA, as of June 1, 2016, for the use in cancer. The cobus EGFR Mutation Test v2 detects key mutations in the EGFR gene that makes patients with advanced non-small cell lung cancer candidates for treatment with the targeted therapy erlotinib (Tarceva®). Others have not been approved, but are certainly on the favorable side of the fence.

Possible Alternative to Traditional Tumor Biopsies

Philip Mack, Ph.D., of the University of California Davis Comprehensive Cancer Center, and lead investigator on the Guardant360 acknowledges that there is much more development and research that needs to be done with liquid biopsies, before their utility in cancer treatment, and diagnosis can be known, but they are useful now. Based on the study’s findings, Mack says “the evidence suggests that liquid biopsies could be an alternative when traditional tumor biopsies are ‘not practical, accessible, or feasible.’”(2)

Liquid Biopsies on Radar

Liquid biopsies should certainly be something on the primary care physician’s radar. They are non-invasive, and have utility in instances where a surgical biopsy is not possible, not enough tissue was obtained through an initial biopsy, metastasis, recurrence of cancer after tumor removal, poor response to treatment, or refusal of a biopsy.

References:

  1. Fantasy No Longer: Blood Biopsies Detect Tumor DNA, Could Catch Cancer Earlier. [transcript]. This moment in cancer. MBUR 90.9. January 30, 2017
  2. NCI Staff.Blood Test for Genetic Changes in Tumors Shows Promise as Alternative to Tumor Biopsy. NIH: National Cancer Institute website https://www.cancer.gov/news-events/cancer-currents-blog/2016/asco- liquid-biopsy. June 14, 2016. Accessed February 4, 2017.
  3. Zill OA, Eltoukhy H, Kurzrock R, et al. Somatic genomic landscape of over 15,000 patients with advanced-stage cancer from clinical next-generation sequencing analysis of circulating tumor DNA. Annual meeting of the American Society of Clinical Oncology (ASCO), Chicago. J Clin Oncol. 2016; 34. Abstract: LBA11501.
  4. Biocept
  5. Guardant360


    Node Smith, associate editor for NDNR, is a fifth year naturopathic medical student at NUNM, where he has been instrumental in maintaining a firm connection to the philosophy and heritage of naturopathic medicine amongst the next generation of docs. He helped found the first multi-generational experiential retreat, which brings elders, alumni, and students together for a weekend campout where naturopathic medicine and medical philosophy are experienced in nature. Three years ago he helped found the non-profit, Association for Naturopathic ReVitalization (ANR), for which he serves as the board chairman. ANR has a mission to inspire health practitioners to embody the naturopathic principles through experiential education. Node also has a firm belief that the next era of naturopathic medicine will see a resurgence of in-patient facilities which use fasting, earthing, hydrotherapy and homeopathy to bring people back from chronic diseases of modern living; he is involved in numerous conversations and projects to bring about this vision. 

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