HER2 Amplification in Brain Metastases May Be Relatively Common in GI Cancer
Brain metastases were HER2-positive in nearly one-third of patients with gastrointestinal primary malignancies, suggesting molecular testing may be prudent.
A single-center study showed that HER2-positive brain metastases in patients with gastrointestinal (GI) primary malignancies were relatively common.1 The study findings were published online October 29, 2018, in The Oncologist.
To determine the incidence of HER2-positive brain metastases, study researchers selected patients with nongastric GI primary malignancies who were treated at Massachusetts General Hospital in Boston. Only patients who underwent craniotomy for brain metastases between 1999 and 2017 were included. In total, 28 patients were selected, 24 of which had tissue from a prior site of disease available for matched analysis.
For 13% of patients, tissue from a prior site of disease, which included brain metastases, was positive for HER2. For nearly one-third of patients, recent brain metastases were HER2-positive. Broken down, HER2was amplified in recent brain metastases for 2 of 3 patients with esophageal squamous cell carcinomas, 3 of 10 patients with esophageal adenocarcinomas, 3 of 14 patients with colorectal adenocarcinomas, and 1 of 1 patients with pancreatic adenocarcinoma. Of those patients with HER2-positive brain metastasis, 37.5% had HER2-positive disease at prior sites, which indicated a high degree of discordance between HER2 status at prior site of disease and recent brain metastasis (κ = 0.38; P= .017).
“The current study shows that brain metastases in patients with GI primary malignancies have a relatively high likelihood of being HER2-positive despite HER2amplification or overexpression being less commonly found in matched tissue from prior sites of disease,” the study authors wrote. “This suggests that regardless of prior molecular testing, patients with GI cancer with brain metastases who have tissue available are likely to benefit from HER2 assessment to identify potential novel therapeutic options.”
- Mitra D, Clark JW, Shih HA, et al. Enrichment of HER2amplification in brain metastases from primary gastrointestinal malignancies[published online October 29, 2018]. Oncologist. doi: 10.1634/theoncologist.2018-0152