Alternate-day S-1 Oral Therapy for Frail Patients With Metastatic Colorectal and Pancreatic Cancer

Standard therapies are difficult to implement in vulnerable patients. S-1 alternative daily therapy has been reported to be a low-burden drug therapy for metastatic colorectal cancer in elderly patients. The vulnerable elders survey-13 (VES-13) is a tool to identify vulnerable elderly patients. In this study, we investigated the utility of simultaneous and serial measurements of the VES-13 and cancer prognostic factors, neutrophil-to-lymphocyte ratio (NLR) and tumor markers (TM), during chemotherapy in patients receiving S-1 every other day.

We studied five patients with metastatic colorectal cancer and eight patients with pancreatic cancer who received S-1 on alternate days. The NLR, TM levels, and VES-13 scores were measured monthly before and during chemotherapy. A scatterplot of NLR on the horizontal axis and TM levels on the vertical axis was plotted together with the VES-13.

The NLR and VES-13 scores showed a positive correlation, and both increased in cases of bowel obstruction or enteritis. Following the evaluation of progressive disease, two patients with colon cancer and two with pancreatic cancer were eligible to switch to the standard treatment regimen.

Alternate-day S-1 therapy appears to be a feasible and effective treatment option for frail patients with metastatic colorectal and pancreatic cancer. Continuous monitoring of the NLR and VES-13 scores can aid in the stratification of patients, ensuring that treatment intensity is appropriately matched to the patient's condition.