How is HER2-positive colon cancer treated?

Updated: Apr 15, 2020
  • Author: Tomislav Dragovich, MD, PhD; Chief Editor: N Joseph Espat, MD, MS, FACS  more...
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Answer

HER2 is overexpressed in approximately 3% of colorectal cancers overall and in 5-14% of RAS/BRAF–wild type colorectal tumors. Experimental therapeutic approaches for tumors that have HER2 overexpression have included trastuzumab plus lapatinib and trastuzumab plus pertuzumab. [92]

In a phase 2 proof-of-concept study, 27 heavily pretreated patients with HER2-positive metastatic colon cancer showed good response to a therapy regimen that is commonly used to treat HER2-positive breast cancer and does not include a chemotherapy backbone. The 27 patients in the study were identified through screening of 914 patients with KRAS exon 2 (codons 12 & 13) wild-type metastatic colorectal cancer. [131, 132]

Most of the patients had extensive metastatic disease and distal colon tumors. Almost 75% had received at least four prior treatment regimens and had spent a median total time of 20 months on previous treatments.

Patients were treated with a combination of trastuzumab and lapatinib. At 1 year, 12 of the 27 patients (45%) were still alive. At a median follow-up of 94 weeks, one patient (4%) had achieved a complete response, seven (26%) had achieved a partial response, and disease had stabilized in 12 patients (44%). [131, 132]


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