Dr. Weinberg on Broad Molecular Profiling in GI Cancers

Benjamin Weinberg, MD, assistant professor of medicine, Division of Hematology and Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, discusses the importance of broad molecular profiling in patients with gastrointestinal (GI) cancers.

Moving forward, clinicians are going to have to be more persistent about performing genetic testing in patients with these various tumor types. There are many genetic alterations that are highly rare, but if detected, they can be paired with effective therapies. NTRK is a good example of this, Weinberg says. Although these mutations only appear in approximately 1% of patients with GI cancers, physicians still need to look for them in every patient.

For example, larotrectinib (Vitrakvi) was approved by the FDA in November 2018 for use in patients with solid tumors that harbor NTRK fusions, and this drug is essentially a “silver bullet” for these patients. There are low rates of HER2 expression and microsatellite instability, as well, but these also have associated treatment options.

Other important molecular defects are homologous recombination deficiency and BRCA mutations, which can be inherited or acquired de novo. These patients have a higher likelihood of responding to platinum-based chemotherapy as well as PARP inhibitors, says Weinberg. As such, future research will be geared toward bringing PARP inhibitors to greater prominence in this space, Weinberg notes.