Gallbladder cancer with EGFR mutation and its response to GemOx with erlotinib: a case report and review of literature

BACKGROUND: Gallbladder cancer (GBC) is the most common and aggressive extra hepatic biliary tree cancer (BTC) with dismal outcome. Complete surgical resection is the treatment of choice. Chemotherapy is used for palliation in advanced GBC where surgery is not possible, and the most commonly used agent is gemcitabine in combination with cisplatin or oxaliplatin or with capecitabine regimens. Complete remissions are hardly encountered in these cases; therefore, it is important to combine standard therapies with molecular targeting. CASE PRESENTATION: A 60-year-old woman presented with pain in abdomen and loss of appetite for 1 month, and imaging showed locally advanced gallbladder carcinoma with liver metastasis. After biopsy confirmation, patient was initially started on gemcitabine and oxaliplatin combination followed by gene sequencing, which showed Tp53 (exon 7—c.713 G > A and exon 5—c.376-2A > G) and EGFR (exon 20—T790M) mutation, and erlotinib was added to chemotherapy, after 6 cycles of chemotherapy patient showed a 90% partial radiological response as per RECIST criteria. CONCLUSION: This case reports the possible efficacy of erlotinib in combination with gemcitabine and oxaliplatin in treating an EGFR-mutated GBC with liver metastasis. To our knowledge, this is the first article reporting the response to erlotinib combination therapy with this particular solitary mutation.