[Unresectable Advanced HER2-Positive Gastric Cancer Leading to a Perforation during Chemotherapy with Trastuzumab plus Paclitaxel].

The patient was a 70s female with gastric cancer. CT and PET scans revealed metastases of para-aortic lymph nodes, hepatoduodenal ligament lymph nodes, and left supraclavicular lymph nodes. She was diagnosed with T4a, N2, M1(LYM), and cStage ⅣB and was given chemotherapy with paclitaxel due to chronic kidney disease and trastuzumab treatment. We planned to perform radical gastrectomy with lymph node dissection due to the disappearance of FDG uptake except for primary gastric cancer on PET scans 5 months after chemotherapy. However, the patient developed pan-peritonitis due to gastric cancer perforation; therefore, emergency distal gastrectomy with Billroth Ⅱ reconstruction was performed. She received chemotherapy(only trastuzumab)after getting discharged. Reports about gastric cancer perforation during chemotherapy using trastuzumab are rare. We should consider the possibility of perforated gastric cancer during chemotherapy and optimal surgical procedures, including the extent of lymph node dissection in the case of Stage Ⅳ gastric cancer.