The team previously demonstrated that circulating hybrid cells (CD45-positive/CK-positive) are found in high numbers in pancreatic adenocarcinoma and are better correlated with overall survival than traditional circulating tumor cells (CTCs, CD45-negative/CK-positive). However, the use of hybrid cells as indicators of response to treatment has not yet been explored
An analysis of 58 peripheral blood samples from patients with rectal and esophageal cancers has shown that circulating hybrid cells may be a new non–invasive biomarker for monitoring treatment response. The research was presented at SSO 2021 (International Conference on Surgical Cancer Care), which took place between March 18th and 19th in virtual format.
Real-time monitoring of treatment response with a liquid biomarker can help inform treatment decisions in patients undergoing neoadjuvant therapies for rectal and esophageal cancers, as well as in patients with metastatic colorectal cancer receiving hepatic arterial infusion therapy.
The team collected peripheral blood samples from patients with rectal and esophageal cancers prior to resection or longitudinally during neoadjuvant treatment and hepatic arterial infusion therapy.
For circulating hybrid cell enumeration, peripheral blood mononuclear cells were isolated and then immunostained for expression of CD45 and cytokeratin. Treatment response was determined according to the tumor regression grading of the American Joint Committee on Cancer.
Fifty-eight samples collected from patients with rectal cancer (n = 23) and esophageal cancer (n = 35) prior to resection and two patients who received hepatic arterial infusion were evaluated. In the neoadjuvant therapy group, 13 (23%) patients had a pathologic complete response, while 37 (66%) had a non-pathologic complete response and 6 (11%) had no response.
Circulating hybrid cell levels successfully discriminated the pathologic complete response from the non-pathologic complete response in rectal and esophageal cancers (area under the curve [AUC] = 0.82; CI 95% = 0.71-0.92; P< 0.001). In patients followed longitudinally during neoadjuvant therapy (n = 2) and hepatic arterial infusion therapy (n = 2), circulating hybrid cell levels decreased by > 90% with initiation of therapy, but increased with dose reductions and prior to clinical evidence of disease progression.
The authors conclude that circulating hybrid cells are a newly discovered biomarker with the potential to noninvasively monitor treatment response and disease progression in patients with gastrointestinal malignancies. Additionally, the level of circulating hybrid cells is predictive of pathologic complete response to neoadjuvant therapy.