Test Identifies Esophageal Cancer Patients Resistant to Chemoradiation Therapy

A proprietary multianalyte test is able to identify which esophageal cancer patients are unlikely to benefit from the standard presurgical treatment of chemoradiation.

The results from a study suggests that up to 30% of esophageal cancer patients may not benefit from the highly toxic, presurgical chemoradiation therapy (CTRT), and instead could have the option of moving directly to surgery and to other treatment options.

The test, called the DecisionDx-EC test (Castle Bioscience; Friendswood, TX, USA) analyzes the localization of three protein biomarkers, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), glioblastoma GLI family zinc finger 1 (Gli1), and sonic hedgehog (SHH), to classify tumors as either responsive to (non-exCTRT) or resistant to CTRT (exCTRT). The test was performed on formalin-fixed paraffin-embedded esophageal cancer tissue.

A study involving 167 patient cases, all of whom underwent a chemoradiation regimen involving 5-fluorouracil (5FU) plus platinum/taxanes showed a specificity of 90% and positive predictive values (PPV) of 64% and negative predictive values (NPV) of 98%. In a second, multicenter validation study involving 64 patient cases, 67% of whom had been treated with a regimen that included 5FU, investigators reported 95% specificity, with a PPV of 88% and a NPV of 83%.

In a parallel study to assess the ability of two preliminary gene signatures to predict responsiveness to chemoradiation therapy in tumor samples from 16 patients, a gene expression profile (GEP) test in development was used for esophageal cancer. The results from this initial study showed that the GEP test predicted treatment response with high accuracy and specificity of 100% and 100%, respectively. The company plans to further evaluate the GEP test in esophageal and rectal cancer.

Sunil Badve, MD, FRCPath, a professor of Pathology and Laboratory Medicine, said, “The standard of care for esophageal cancer, which includes presurgical chemoradiation to reduce tumor bulk prior to surgical resection, is not effective for up to 30% of patients. The ability to identify those patients least likely to benefit from the therapy is an important advancement in managing a patient's disease, allowing them to avoid the toxicities and the delay of surgery and more effective approaches.” The study was presented at the 11th Annual Meeting of the International Society of Gastrointestinal Oncology held October 23–24, 2014, in Arlington (VA, USA).

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