[Good remission under HER2 blockade in an advanced carcinoma of the oesophagogastric junction with only focal HER2 overexpression].

We report an 80 year old male patient diagnosed with an advanced adenocarcinoma of the oesophagogastric junction (uT3 uN + cM0; Siewert II). The initial external HER2 test was negative (HER2 value 1 +) but was repeated in-house. On the basis of more extensive biopsies focal but strong HER2 positivity (HER2 value 3 +, ~10 % of the tumor cells positive) was demonstrated. The patient subsequently received a combination of oxaliplatin, 5-fluorouracil/folinic acid and trastuzumab, resulting in an improvement of symptoms and a tumor regression. The discrepancy of the two HER2 tests performed was caused by heterogeneity of HER2 expression, not detectable during initial sampling due to a low number of tumor containing biopsies. In addition, uncertainties of the HER2 scoring algorithm of oesophagogastric cancer samples could have played a role. This case report illustrates that oesophagogastric carcinoma with an only minor HER2 positive clone may benefit from an anti-HER2 therapy in combination with chemotherapy. It also describes problems and challenges associated with HER2 testing of oesophagogastric carcinoma, especially when only a few tumor-bearing biopsies could be obtained. PMID: 28787750 [PubMed - as supplied by publisher]
Source: Zeitschrift fur Gastroenterologie - Category: Gastroenterology Authors: Tags: Z Gastroenterol Source Type: research