To investigate the correlation between peripheral blood neutrophil percentage-albumin ratio (NPAR) and breast cancer, and to evaluate its clinical predictive efficacy for breast cancer.

A total of 109 patients with malignant breast tumors (malignant group), 94 patients with benign breast tumors (benign group) from January to December 2016 were enrolled, and 100 healthy women during the same period were included as the control group. Peripheral blood neutrophil percentage and serum albumin level were measured in the three groups, and NPAR was calculated. Intergroup differences in the indicators were analyzed by statistical methods. Binary Logistic regression was used to explore the correlation between NPAR and the risk of breast cancer, and ROC curve was applied to assess its diagnostic value.

NPAR and neutrophil percentage in the malignant group were significantly higher than those in the benign group and healthy group, while serum albumin level was significantly lower than that in the latter two groups. The difference in NPAR among the three groups was statistically significant (P<0.05). In the malignant group, there were no statistically significant differences in NPAR among subgroups with different clinical characteristics, including molecular subtypes, axillary lymph node metastasis status, and histological grade (P>0.05). Multivariate Logistic regression analysis showed that NPAR was a significant risk factor for breast cancer before adjustment for age (P<0.05), but the correlation disappeared after age adjustment (P=0.820), whereas age was an independent risk factor for breast cancer (OR=1.077, 95%CI: 1.043-1.113, P<0.001). Peripheral blood neutrophil percentage and serum albumin showed no significant statistical correlation with the incidence of breast cancer (all P>0.05). ROC curve analysis revealed that the AUC of age for differentiating breast cancer from benign breast tumors was 0.747 (95%CI: 0.680-0.815), with an optimal cutoff value of 45.5 years, a sensitivity of 61.5% and a specificity of 76.6%. The area under the curve (AUC) of NPAR for distinguishing breast cancer from benign breast tumors was 0.732 (95%CI: 0.667-0.797), with an optimal cutoff value of 11.88, a sensitivity of 75.2% and a specificity of 61.7%. The combined use of age and NPAR for differentiating breast cancer from benign breast tumors yielded an AUC of 0.799 (95%CI: 0.739-0.859), with a sensitivity of 75.2% and a specificity of 74.5%.

NPAR differs significantly among patients with malignant breast tumors, benign breast tumors and healthy individuals. It is associated with breast cancer risk before age adjustment, but its effect is confounded or modulated by age. Age is a definite independent risk factor for breast cancer, while the evidence supporting NPAR as an independent risk factor for breast cancer is insufficient. Detection of NPAR can assist in the clinical identification of breast cancer, but its clinical application value still needs to be further verified by large-sample and multicenter studies.