Readers Write: Liquid biopsies may slow global cancer deaths


“Not every cancer is aggressive or lethal. Some cancers may be so slow growing that they would never need treatment. We need better methods to differentiate which ones can be left alone and which ones need to be treated.” Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society.

Certain cancer therapies provide better patient outcomes and fewer side effects than broad-based chemotherapy, but an individual’s response to a given treatment often depends on the tumors “genomic profile.”

A liquid biopsy is an advanced form of treatment procedure for cancer wherein bodily fluids like blood or urine are collected for disease detection. A liquid biopsy helps in planning a  treatment regime along with finding out effective treatment options for the patient.

A biopsy as defined by Zion Market Research is a tissue or cell sample taken from any part of the human body, which is sent to the lab for examining various disease types

The  trick with liquid biopsies is to find trace amounts of DNA that have broken off from tumor cells.  These circulating tumor DNAs are tiny fragments of DNA in the blood that break away from tumors. After treatment, according to Lichtenfeld, these DNA levels decrease because either the tumor is smaller or has been removed. Now the researchers monitor the DNA levels in the blood to watch for increases over time. This oncology “pipe dream,” so described by Maxx Chatsko in TMFBlack Gold, really might live up to the hype and reduce the need for risky and invasive tissue biopsies.

A genomic profile is a laboratory method that is used to learn about all the genes in a person or in a specific cell type, and the way those genes interact with each other and with the environment. Genomic profiling may be used to find out why some people get certain diseases while others do not or why people react in different ways to the same drug. It may also be used to develop new ways to diagnose, treat, and prevent diseases such as cancer.

Now the discussion is what do we use liquids biopsies for at this early stage of development.

Advanced stage cancer patients have significantly more circulating DNA compared to early stage cancer patients, and so the data extracted from a simple blood draw could be used to fine-tune treatments for individuals with cancer, detect recurrence, and even find cancer in individuals during routine checkups and blood draws when it is the easiest to treat and cure.

At present, there is a patient population in the United States of approximately 700,000 advanced cancer patients and about 15 million early cancer patients and survivors. The DNA “garbage” circulating in the blood in advanced cancer patients can help patients match up with the best treatment options.  Results would be more easily demonstrated and treatment better targeted.

It will also provide expansive genomics data to bio pharma companies developing immuno oncology drugs. It is expected that as we learn more about liquid biopsies and the use of DNA and gene data, we will be able to monitor early stage patients and measure drug resistance in recurrent disease. A  new study written about in “Targeted Oncology” shows the compatibility between liquid biopsy and tissue biopsy in both diagnostics and the monitoring of non-small cell cancer, NSCLC. The results seem to show it may be preferable to help oncologists make swifter decisions that help manage the disease.

A sample from sticking a needle into a tumor doesn’t reflect all the genetic changes of that cancer or all the places that cancer may be, Lichtenfeld says. But the DNA “garbage” circulating in the blood sort of acts like a vacuum cleaner, bringing together all the DNA fragments and finding other mutations that may be elsewhere, so the two tests — a biopsy of the solid tumor and a liquid biopsy — are definitely complementary.

A goal of the liquid biopsy is to use the DNA in the blood to learn that a person may have cancer somewhere in the body before it is easily visible by current techniques, such as colonoscopy, mammography, X-rays or CT-Scans. The very fact that the cancer is not yet visible means doctors need a screening tool that gives them some guidance about where to look, Lichtenfeld says.

Nicole Tucker, writing in “Targeted Oncology” says that liquid biopsy, in general, is faster than tissue biopsy because the processing and characterization of the tissue biopsy is not required for blood. The turnaround time of six days for liquid biopsy and 10 days for tissue biopsy from sample reception to the delivery of the report was four days less for liquid. This may not seem like a big time difference unless you are the patient waiting to hear if you do or do not show positive results for cancer.

Their ability to pin down the cancer’s location varied between where it started in the body. The best results were with colorectal and ovarian cancers. The least accurate results were with liver and lung cancers.

Most important, the sooner the physician received the results, the sooner the patient could begin receiving treatment.

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