Novel Blood-Based Biopsy Shows High Accuracy in Detection of Lymph Node Metastasis in CRC Specimens

A novel liquid biopsy test for the detection of lymph node metastasis in individuals with high-risk submucosal (T1) colorectal carcinoma has been developed, according to a press release from the City of Hope Comprehensive Cancer Center.¹

The assay was shown to be effective for detecting lymph node metastasis in a laboratory study and is hypothesized to be able to limit the need for surgery in high-risk early-stage colorectal cancer (CRC) as well as those with high-risk disease by conventional risk classification criteria. In addition, the identification of metastatic lymph nodes in these patients may lower expense and improve the overall management of patients with CRC.^1,2

“Since radical surgery dramatically reduces the quality of life for patients, improving the success rate of identification of high-risk individuals with lymph node metastasis remains the challenge in T1 colorectal cancer diagnosis,” Ajay Goel, PhD, MS, chair of the Department of Molecular Diagnostics and Experimental Therapeutics at City of Hope, and the study’s senior author, said in a statement. “In the future, we hope to improve our confidence in identifying which individuals truly have lymph node metastasis via this novel biomarker-based liquid biopsy test for T1 CRC, in combination with clinical and pathological criteria.”

Due to recommendations from the National Comprehensive Cancer Network, a minimally invasive surgery known as endoscopic submucosal dissection is the standard of care for this patient population. However, Goel et al believe that the current criteria for stratifying the risk of lymph node metastasis are out of date and often lead to the overtreatment of patients.

In the study, 330 specimens from patients with high-risk T1 CRC were analyzed. The goal was to establish a risk-stratification model that combines transcriptomic biomarkers along with clinical risk factors.²

The discovery of metastatic lymph nodes in the CRC population was robust (area under the curve [AUC], 0.86; 95% CI, 0.72-0.94), according to the published research. The performance of the panel was then validated (AUC, 0.82; 95% CI, 0.74-0.88). When looking at risk stratification, the novel liquid biopsy test appeared to more accurately identify lymph node metastasis in patients (odds ratio [OR], 37.17; 95% CI, 4.48-308.35; P < .001). The multivariate analysis showed an OR of 17.28 (95% CI, 1.82-164.07; P = .013).

Overall, the study showed that the novel liquid biopsy test performed with an 83.3% sensitivity, 76.2% specificity, 24.4% positive predictive value, and 98.0% negative predictive value.

“Obtaining results with more than 80% accuracy in finding lymph node metastasis in the blood was a completely unexpected finding and is a complete game changer,” Goel said. There are several steps between where we are now and where we want to go — detecting lymph node metastasis in colon cancer from a blood sample — but without doubt this is an encouraging first step.”

The data supporting the use of this blood-based biopsy are retrospective and early. Goel et al suggest conducting further independent prospective studies to confirm the potential of this assay before it can be used in clinical practice.

_References:

_{1. City of Hope scientists develop a novel, noninvasive liquid biopsy test for identification of lymph node metastasis in early-stage T1 colorectal cancer. News release. City of Hope. April 21, 2021. Accessed April 22, 2021. https://bit.ly/2QI5MdH}

_{2. Wada Y, Shimada M, Murano T, et al. A liquid biopsy assay for noninvasive identification of lymph node metastases in T1 colorectal cancer. Gastroenterology. Published online April 2, 2021. doi:10.1053/j.gastro.2021.03.062}