Dr. Maron on HER2-Positive Tumors in Esophageal Gastric Cancers

Steven Maron, MD, MSc, medical oncologist, Gastrointestinal Malignancies, Esophageal and Gastric Cancers, Targeted Therapies, Memorial Sloan Kettering Cancer Center, discusses HER2-positive tumors in esophageal gastric cancers.

Not all HER2-postive tumors are the same, as some are more heterogeneous, with HER2 positivity between 5% and 50%, and some are homogeneous and more HER2-positive, Maron says. Patients with stronger HER2expression typically have better outcomes, Maron adds.

Problems can arise in patients with HER2-positive tumors due to a resistance mechanism that is present at the onset of disease, Maron adds. Approximately one-third of patients no longer have HER2 expression after receiving HER2-directed therapy, Maron explains. When the remaining patients experience disease progression or recurrence, an escape mechanism is present in the form of another mutation, such as EGFR, MET, FGFR2, or PI3K, Maron explains.

Current strategies involve exploring ways handle these resistance mechanisms, rather than using alternative HER2 inhibitors, Maron continues. Antibody-drug conjugates are being used to deliver chemotherapy or radiation with HER2 expression used more as a locator to deliver the treatment payload, Maron concludes.