Liquid Biopsy: Using Tumor DNA to Detect and Treat Cancer

Early diagnosis has always been instrumental in improving a patient’s chances when it comes to treating cancer. If the tumors are detected early on and removed, then the probability of them metastasizing is also significantly removed. However, finding cancer has always been tricky. Most cancers do not show symptoms until they have progressed too much, and by then it is too late. In the instances when cancer is caught early lays the difference between completely being cured and at risk of remission for patients. For this matter, medical professionals are doing their best to find an effective form of testing that will accurately predict a patient’s future before the cancer even develops.

What are Biopsies?

During a routine checkup, doctors may come across suspicious lumps or tissues in the patient’s body, which can be indicative of diseases such as cancer. When they see these questionable tissues, they often perform a biopsy. A biopsy is a procedure where a sample is collected from a disputed site (such as a lump). This sample is submitted to a laboratory, which then tests and examines it for signs of diseases.

The appearance of these collected cells under the microscope can help doctors and medical professionals make informed decisions about the patient’s health. They will be able to see if there is cancer in the samples, what type of cancer it is, and how far along it is. The molecular analysis of a tissue biopsy sample can also help doctors come up with a personalized treatment strategy for the patient.

While they are very effective and straightforward, taking tissue biopsy samples are unfortunately not always possible. The abnormal growth may be located in a place that is too painful to excise, and some of the biopsy procedures may be invasive. Some require the use of large needles, while others need an endoscope and even an open surgery. For instance, a colonoscopy is normally required to diagnose colon cancer. A colonoscopy is an invasive procedure which requires for the patient to put under anesthesia. It is a costly procedure, and one that puts patients on an edge since it requires them to go under.

Aside from the involved risks, costs, and comfort levels of patients, some also have health conditions that make excising tissue biopsies impossible.

What are Liquid Biopsies?

This is where liquid biopsies come in. According to the National Cancer Institute (NCI), a liquid biopsy is “A test 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.” It may be used to find cancer even if it has not yet developed, or while it is still very early. Doctors may see the molecular changes within the tumor and, in doing so, have a more accurate idea plan as to how to approach the treatment and what is working the best for the patient.

Various studies have explored the efficacy of tapping liquid biopsies for cancer diagnosis, treatment, and management, and while there have been great strides, more information is needed. However, liquid biopsies are becoming more and more popular, particularly for the reason that the information they provide is invaluable. Taking samples are also deemed as very affordable and non-invasive, as they are as simple as getting urine, saliva, or blood samples.

How do Liquid Biopsies Work?

Liquid biopsies work on the premise that cancerous tumors shed cells and molecules throughout the body. These cells and molecules, also known as tumor DNA, then leaves traces into the body. Through liquid biopsy samples, researchers look for cancer indicators in exosomes, proteins, RNA, and whole cells. What makes it all the more appealing is that the tumor DNA can be excised in non-invasive manners, such as through a cotton swab for a saliva sample, and even through a urinalysis.

Researchers are now focusing on circulating tumor DNA (ctDNA), which has shown to be promising in terms of aiding cancer diagnosis. A liquid biopsy test that is being developed right now is one where the sample is tested for ctDNA to detect cancer at an early stage. In fact, several studies had shown that these ctDNA-based liquid biopsies were able to pinpoint cancer months before patients were tested using traditional methods, such as imaging tests.

Yet as the technology is still being tested, there is still a lot of room for error. For instance, while the ctDNA-based liquid biopsies were able to detect early cancer, there were also some cases of false positives. A false positive test result occurs when the patient does not actually have tumor DNA in his sample, but the test labeled it as positive.

Aside from false positives, another concern from the medical community is how sometimes even slow-growing tumors are detected, which triggers unnecessary treatment. With slow-growing tumors, the cancer will progress very, very slowly, so that the patient will not be harmed at all. In some instances, despite the presence of tumors, it will not continue to grow at all! So patients who therefore get treatments for slow-growing tumors are at risk of overtreatment.

Precise Treatments

Another possibility for liquid biopsies is how they can help physicians come up with a precise treatment plan for their patients. This is done by examining the unique molecular characteristics of the patient’s tumor, and monitoring how these molecules react to the medication over a period of time. Since drawing sample is very easy and is non-invasive, the doctors will then be able to see the mutation of the ctDNA and determine how the cancer is progressing.

This is certainly an advancement the medical community will be able to take advantage of in the future.

A Word of Advice

At the end of the day, these medical advancements will make a significant difference to the community. The treatment plan for patients will be even more comprehensive, in the sense that it would be adjusted based on how their bodies react to the medication on a molecular level. If you are interested in more holistic approaches to cancer treatments, you can contact us at 480-757-6573 to discuss your options.

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