Development and validation of a nomogram for predicting survival on the base of modified lymph node ratio in breast cancer patients

Background: Axillary lymph node status is one of the most important prognostic factors in breast cancer and previous studies indicated that lymph node ratio (LNR) could better predict the outcome than the counting of positive lymph nodes. In the current study, we evaluated the prognostic effect of modified LNR in breast cancer patients.

Methods: A total of 3339 breast cancer patients undergoing axillary lymph nodes dissection were enrolled and respectively analyzed. Seventy five percent of participants were randomly selected as training cohort and the remaining 25% were as validation cohort. Univariate and multivariate analyses were performed and the prognostic impact of mLNR was compared with pN staging. A prognostic nomogram was established and externally validated in the validation cohort.

Result: In multivariate analysis, both the mLNR and pN staging were independent prognostic factors for breast cancer patients, and the mLNR manifested superior discrimination power than the pN stages regardless of the total number of lymph nodes retrieved and the lymph node status. The nomogram was built including the identified independent prognostic factors and the calibration curves indicated optimal agreement between nomogram prediction and actual observation. The Concordance index (C-index) of the nomogram was statistically higher than that of the TNM system (0.747 vs. 0.711 in training cohort, 0.789 vs. 0.760 in validation cohort, both p < 0.05).

Conclusion: Modified LNR is an important prognostic parameter and can predict survival more accurately than pN staging. The novel nomogram could provide individual prediction for breast cancer patients and help clinicians in treatment option making and prognosis evaluation.