S-1 in Patients with Advanced Esophagogastric Adenocarcinoma: Results from the Safety Compliance Observatory on Oral fluoroPyrimidines (SCOOP) Study

S-1-based regimens have been shown to be as effective as other fluoropyrimidine-based regimens with a better safety profile in patients with advanced esophagogastric adenocarcinoma. However, real-world data on S-1 in European patients with advanced esophagogastric adenocarcinoma are lacking. The Safety Compliance Observatory on Oral fluoroPyrimidines (SCOOP) study evaluated safety and relative dose intensities for patients treated with S-1-based regimens for advanced esophagogastric adenocarcinoma as part of daily practice. Overall, data for 125 patients with advanced esophagogastric adenocarcinoma were collected at 21 centers in five countries in Europe. Demographics, treatment, and adverse-event data were recorded over a planned treatment of six cycles. Most patients (87%) received combination treatment of S-1 plus a platinum compound. Adverse events related to S-1 treatment were mostly grade 1 or 2 while reported grade 3–4 serious adverse events related to S-1 occurred in 12 patients and were most often grade 3 neutropenia (n = 4, 3.2%) or diarrhea (n = 5, 4%). The most common adverse events of any grade that were attributable to S-1 treatment included neutropenia, anemia, thrombocytopenia, diarrhea, nausea, vomiting, and fatigue. No patients experienced mucositis, dehydration, or febrile neutropenia, whereas 2% (3/125) of patients experienced hand-foot syndrome. The overall relative dose intensity was 70%. In a real-world setting, patients with advanced esophagogastric adenocarcinoma tolerated S-1 treatment well with high compliance rates. The SCOOP study provides valuable information on S-1 relative dose intensity that can be used for treatment decision making.