Daniel V. Catenacci, MD: What cytotoxic regimen do I use for the first-line treatment of metastatic gastric and G [gastroesophageal]-junction cancer? Generally, the go-to regimen is a doublet chemotherapy with fluoropyrimidine and platinum. The preferred platinum is oxaliplatin, so FOLFOX [folinic acid, fluorouracil, and oxaliplatin] chemotherapy is the general go-to first-line chemotherapy for our patients.

Salah-Eddin Al-Batran, MD: As a first-line regimen in the treatment of gastric cancer, we usually use a doublet consisting of oxaliplatin and fluoropyrimidine, either capecitabine or 5-FU [fluorouracil] or S-1 [tegafur, gimeracil, oteracil]. We sometimes use cisplatin, but in most patients, we would prefer doublets of oxaliplatin and fluoropyrimidine, like XELOX [capecitabine and oxaliplatin] or FOLFOX. In some patients, however, we also use triplets: most often FLOT, which is 5-FU, leucovorin, oxaliplatin, and docetaxel. I would say that we only use triplets in young, fit patients requiring intensive treatment. Approximately 20% of our patients would receive a triplet, but the majority of patients are treated with a doublet.

Kei Muro, MD: We in Japan, and many other Asian countries, commonly use fluoropyrimidine plus platinum doublet therapy as the standard of care first-line treatment for advanced gastric cancer. On the other hand, in addition to doublets, triplet regimens such as FLOT [fluorouracil, leucovorin, oxaliplatin, docetaxel] or DCF [docetaxel, cisplatin, fluorouracil] are often considered as the standard of care first-line treatment in Western countries.

Furthermore, Asian GI [gastrointestinal] oncologists, including Japanese oncologists, prefer oral fluoropyrimidine agents, such as S-1 or capecitabine. SOX [tegafur, gimeracil, oteracil plus oxaliplatin], CAPOX [capecitabine and oxaliplatin], S-1, or capecitabine plus cisplatin regimens are widely used. Of course, FOLFOX is frequently administered in poor oral intake cases or peritoneally disseminated patients, which is very prevalent in advanced gastric cancer.

Why are there such different treatment approaches between Asia and the West? In Asia, especially in Japan, it is common for gastric cancer to be treated sequentially: first, second, third, and fourth line, and so on. However, in Europe and the United States, patients often end up on second-line therapy at most.

Salah-Eddin Al-Batran, MD: In terms of molecular testing, we test all patients in the first-line setting for HER2 [human epidermal growth factor receptor 2] overexpression. HER2 is the most established biomarker in gastric cancer, so every patient will be tested for HER2. In terms of other biomarkers, like MSI [microsatellite instability] or PD-L [programmed cell death-ligand] score, these biomarkers are tested later in the course of treatment in most cases, prior to second-line or third-line therapy. We also use NGS [next-generation sequencing], but not prior to first-line therapy. Currently, NGS is done later in the course of the treatment.

Transcript Edited for Clarity