Systemic chemotherapy combined with anti-epidermal growth factor receptor antibody therapy for RAS wild-type appendiceal signet-ring cell carcinoma: a series of three cases.

The effect of anti-epidermal growth factor receptor (EGFR) antibody-containing chemotherapy on appendiceal signet-ring cell carcinoma (SRCC) remains unknown. Herein, we report three patients, diagnosed as having synchronous metastases, who underwent this treatment for unresectable appendiceal SRCC with RAS wild type. Cases 1, 2, and 3 received FOLFOX with panitumumab, FOLFOX with cetuximab, and FOLFIRI with cetuximab, respectively, and their progression-free survival were 6.2, 7.2, and 18.7 months, respectively. The subsequent anti-vascular endothelial growth factor antibody-containing therapy was ineffective, and their overall survival was 8.2, 11.4, and 22.9 months, respectively. The anti-EGFR antibody-containing chemotherapy showed moderate efficacy for appendiceal SRCC. Further studies including molecular analysis should be needed. © The Japan Society of Clinical Oncology 2021.