Measurable Krukenberg tumor is preferably characterized as a non-target lesion in the clinical evaluation of gastric cancer therapeutics: A case report.

Metastatic cystic lesions may be considered as target lesions according to the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. However, cystic lesions are considered as non-measurable according to RECIST 1.0. Krukenberg tumors are cystic metastases from gastric cancer. The aim of the present case report was to address the question of whether a Krukenberg tumor can be considered as a target lesion. A 30-year-old female patient was diagnosed with stage IV gastric cancer 6 months after parturition. Subsequently, the patient received two courses of oxaliplatin/capecitabine plus trastuzumab (OCT) treatment. The response evaluation was considered as stable disease. However, after four courses of OCT, the cystic target lesion in the right pelvic cavity exhibited an increase in diameter of >40%. After one more cycle of OCT, contrast-enhanced magnetic resonance imaging (MRI) revealed that the diameter of the cystic mass lesion had decreased by >35% and a further two cycles of treatment were administered. After the last OCT cycle, the levels of the tumor markers cancer antigen (CA) 125, CA19-9 and CA153 had markedly increased, although the cystic mass had decreased in size. Eventually, positron emission tomography-computed tomography (PET/CT) was used to assess the efficacy of treatment. A new lesion was identified, indicating progressive disease. The present case demonstrated that the Krukenberg tumor may be considered as a non-target lesion. In addition, tumor markers and PET/CT yielded results complementary to those of contrast-enhanced MRI in the therapeutic assessment of advanced gastric cancer.