Risk factors for N2 metastasis in patients with non-small-cell lung cancer: multivariate analyses of 18F-FDG PET/CT...

N staging is a key factor when considering the choice of treatment for non-small-lung cancer. It is possible that there is a correlation between N2 metastasis and some risk factors. The objective of the present study was to evaluate associations between several risk factors and N(2) metastasis using univariate and multivariate analyses, which may assist clinicians in therapeutic planning.

The enrolled patients were divided into two groups on the basis of histopathological results after surgery: those with pN(2) disease (N(2) group) and those without (N(2) group). Sex, age, location, size, maximum standardized uptake value (SUV(max)) on fluorine-18 fluorodeoxyglucose PET, histopathological type, and tumor cell grade were compared between N(2) and N(2) groups. Correlations between each significant factor and groups were analyzed using univariate analyses. Independent risk factors were finally identified with multivariate analyses.

A total of 258 patients met the inclusion criteria. Univariate analyses showed significant correlation between size, SUV(max), tumor cell grade, and N(2) status (P<0.05). Multivariate logistic regression showed that both SUV(max) and tumor cell grade were independent risk factors and had predictive value for N(2) disease (P<0.05). There were no N(2) node metastases when tumor SUV(max) was up to 2.5 and the tumor cell grade was low. However, the likelihood of metastasis increased to 0.29 and 0.28 when tumor SUV(max) was greater than 7.5 and when the tumor cell grade was high.

SUV(max) and tumor cell grade are independent risk factors for N(2) metastasis.