Ninjin'yoeito is associated with attenuation of postoperative decline in Prognostic Nutritional Index in patients with oral squamous cell carcinoma: a single-center, open-label, single-arm study.

BACKGROUND: Postoperative nutritional deterioration and immunosuppression are clinically important in patients undergoing surgery for oral squamous cell carcinoma (OSCC). The Prognostic Nutritional Index (PNI), calculated from serum albumin and total lymphocyte count, is associated with the prognosis of OSCC. Ninjin'yoeito (NYT), a traditional Japanese Kampo medicine, has been reported to exert orexigenic and immunomodulatory effects. We evaluated whether perioperative NYT administration was associated with attenuation of postoperative PNI decline in patients with OSCC. METHODS: This single-center, open-label, single-arm interventional study was conducted at Kagoshima University Hospital, approved by a Certified Review Board, and registered with the Japan Registry of Clinical Trials (jRCTs071230055). Patients with OSCC scheduled for curative surgery received NYT (7.5 g/day) from the preoperative period through postoperative week 8. The primary endpoint was the change in PNI from baseline to postoperative week 8, compared with a prespecified historical threshold (-4.95) using one-sample t-test. Secondary endpoints were summarized descriptively with 95% confidence intervals (CIs). RESULTS: Nineteen patients completed the study protocol and were included in the efficacy and safety analyses. The mean change in PNI at postoperative week 8 was -2.576 (95% CI, -4.743 to -0.410), which was significantly better than the historical threshold (p = 0.0335). The exploratory secondary outcomes, including body weight and selected inflammatory indices, showed postoperative trajectories compatible with gradual recovery during follow-up. No grade ≥3 treatment-related adverse events or serious adverse events were observed. Given the single-arm design with a historical comparator, these findings should be interpreted cautiously and warrant confirmation in controlled trials. CONCLUSION: Perioperative NYT administration was associated with attenuation of postoperative PNI decline in patients undergoing OSCC surgery. NYT was well tolerated, supporting the feasibility of its perioperative use. Controlled trials are warranted to confirm clinical benefits and evaluate long-term outcomes of NYT use.