Nutritional indices are potentially important prognostic biomarkers before chemotherapy for non‑specific subsets of cancer of unknown primary origin

Patients with cancer of unknown primary origin (CUP) account for 2‑5% of all types of cancer worldwide and have a poor prognosis, with a reported 1‑year survival rate of ~20%. Furthermore, global data indicate that in patients with unfavorable subsets, the median overall survival (OS) is ~12 months from the initiation of first‑line therapy; however, reliable prognostic biomarkers in patients with the unfavorable subset are yet to be elucidated. As nutritional indices are used as prognostic factors in various malignancies, such as gastrointestinal cancer, the present retrospective study aimed to examine the impact of nutritional status on the prognosis of patients that underwent chemotherapy for CUP. The association between four indices of nutritional status and OS and progression‑free survival (PFS) was investigated in 25 patients with CUP who received chemotherapy at Kurume University Hospital (Kurume, Japan) between July 2011 and June 2023. Nutritional status was evaluated using the prognostic nutritional index, neutrophil‑to‑lymphocyte ratio (NLR), modified Glasgow prognostic score (mGPS) and controlling nutritional status (CONUT) score. Low NLR (≤3), mGPS (0‑1) and CONUT (0‑3) scores indicated good nutritional status. The median PFS and OS for all patients were 6.3 and 17.2 months, respectively. Univariate analyses revealed that low mGPS [hazard ratio (HR), 0.27; 95% confidence interval (CI), 0.09‑0.80; P=0.017) and CONUT (HR, 0.23; 95% CI, 0.07‑0.75; P=0.015) scores were favorable prognostic factors for OS. Furthermore, a low mGPS (HR, 0.21; 95% CI, 0.08‑0.61; P=0.004) score was predictive of favorable PFS. Multivariate analyses revealed that low mGPS (HR, 0.21; 95% CI, 0.05‑0.94; P=0.041) and CONUT (HR, 0.20; 95% CI, 0.05‑0.90; P=0.035) scores, and a low mGPS (HR, 0.20; 95% CI, 0.06‑0.71; P=0.012) score, were independent prognostic factors for OS and PFS, respectively. In conclusion, a good nutritional status (as indicated by low mGPS and CONUT scores) independently predicted a potentially favorable prognosis in chemotherapy‑treated patients with CUP. These results may be used in order to estimate prognosis before chemotherapy.