Liquid biopsy for colorectal cancer may lead to treatment of tumors

A new study from Washington University in St. Louis’ School of Medicine shows that liquid biopsy, which examines blood or urine, helps measure the effectiveness of treatment for colorectal cancer that has just begun to spread beyond the original tumor. Such biopsies can detect protracted disease and guide the patient in deciding whether further treatment should be given for some tumor cells that avoid the first attempt to eradicate the cancer. May be useful as.

The study will be displayed online on February 12th Journal of Clinical Oncology Precision Oncology, Journal of the American Society of Clinical Oncology.

Some liquid biopsies are approved by the Food and Drug Administration, but mainly in the lungs, breasts, ovaries, and Prostate cancer, Nothing approved Colorectal cancer..

Patients in this study had what is known as oligodendable colorectal cancer. This means that each patient’s cancer has spread beyond the original tumor to only a few sites.Such patients chemical treatment Shrinking the tumor before surgery to remove the rest of the primary tumor. Should oligodendant metastatic cancer be treated like metastatic cancer with more chemotherapy after initial treatment, or should it be treated like local cancer with more surgery and radiation therapy in those limited areas? There is debate in this area.

The cause of this problem is the ability of physicians to predict how patients will respond to early chemotherapy, especially because most patients do not have access to cancer genomic sequencing to identify DNA mutations in the original tumor. It’s limited.

“Being able to measure response to early chemotherapy without prior knowledge of tumor mutations is a novel idea and important to help patients determine if they have responded successfully to treatment,” he said. The author, Dr. Adel A. Chauduri, MD, said. .. , Associate Professor of Radiation Oncology. “This can provide guidance on how to treat metastatic disease, for example. Liquid biopsy It shows that the patient responded well to early chemotherapy. Perhaps they should be offered more surgical potential that could cure their illness. However, if they do not respond well, the cancer is likely to be too widespread to be eradicated by surgery, and those patients should receive more chemotherapy to control their disease. “

Liquid biopsy for colorectal cancer is isolated from the cancer and circulates in the blood to detect, to a lesser extent, tumor DNA collected in the urine. The biopsy described in this study is unique compared to other liquid biopsies being developed for colorectal cancer in three major ways. First, most such biopsies were developed to track metastatic cancer or to confirm that local cancers have not begun to spread. Second, most liquid biopsies of cancer rely on their knowledge of mutations in the original tumor to determine if those mutations are still present in the blood after treatment. However, many patients do not have the opportunity to sequence the original tumor. Instead, new biopsies rely on detecting DNA mutations in blood or urine, surgically removing them, and then comparing them with the DNA mutations measured in the treated primary tumor.And finally, urine biopsy Most urine biopsies are specific to colorectal cancer because they are limited to use in genitourinary cancers, especially bladder cancer.

“The level of circulating tumor DNA that could be measured in urine was lower than that measured in blood, a proof of concept that this completely non-invasive method could measure residual disease of non-urinary cancer. “Cauduri, who also treats patients at the Sightman Cancer Center at Burns Jewish Hospital and the University of Washington School of Medicine, said:” To make this a useful clinical trial, urinary colon-rectal tumor DNA We need to develop a more sensitive technology for detecting urine, but this is a promising start. “

This study showed that lower circulating tumor DNA levels correlate with a better response to early-stage chemotherapy. Indeed, most patients who had undetectable levels of tumor DNA in their blood samples also had no measurable cancer in their surgical specimens.

There was also evidence that residual lesions detected in liquid biopsy were more predictive of outcome than residual lesions found in surgical specimens. For example, researchers described the experience of a man whose cancer was still removed during surgery after initial chemotherapy to shrink or eliminate the tumor. However, his blood sample taken that same day did not show circulating tumor DNA. He experienced long-term survival without cancer recurrence. On the other hand, women who had no detectable cancer cells in the surgical specimens removed after early chemotherapy were found to be circulating. tumor DNA in her same day blood sample. Eight months later, the cancer returned to her liver.

This study suggests that such liquid biopsy may help personalize the treatment of metastatic colorectal polyps. cancer.. A new study will identify patients at high risk of recurrence and help them make decisions about which conventional treatments to use, as well as those who may benefit from immunotherapy and other targeted therapies. Also identified.

Based on “mutation blood A biopsy was able to identify patients who might benefit from immunotherapy called immune checkpoint inhibitors after the initial treatment was completed. Mutations have also been found that may be targeted by drugs approved for other cancers. Although our current research is observational, it paves the way for designing future clinical trials that can test some of these potential therapies. ”

For more information:
Pellini et al. Detection of ctDNAMRD and personalized tumor genome analysis in plasma and urine metastatic colorectal cancer. JCO Precision Oncology.. February 12, 2021.