Tanin Titipungul1 M.D., Piyapharom Intarawichian2 M.D., Sakda Waraasawapati2 M.D., Sakkarn Sangkhamanon2 M.D., Nipon Chaisuriya2M.D., Chawalit Pairojkul2 M.D., Yaovalux Chamgramol2 Ph.D. 1Department of Pathology, Mahasarakham Hospital, Mahasarakham, Thailand 2Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand Correspondence :Yaovalux Chamgramol, Ph.D. Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand. Tel : +66-43-363691, Fax. +66-43-348388 E-mail : firstname.lastname@example.org Received : 10 February 15 ; Accepted : 18 March 15
Background : The number of metastatic lymph nodes to the total number of dissected axillary lymph nodes (lymph node ratio: LNR) is described as an independent prognostic factor in breast cancer patients, beside the traditional account of the number of axillary lymph node metastasis (pN stage). We investigated the correlation between LNR and prognosis among Thai patients with invasive breast cancer. Materials and methods : We retrospectively analyzed the prognostic value of LNR from the survival outcomes in patients with non-metastatic breast cancer from the medical records of 122 female Thai patients who underwent modified radical mastectomy, from 2009 to 2011. The median length of follow-up was 44 months. Based on the LNR, the patients were divided into low (LNR 0.01-0.20), intermediate (LNR 0.21-0.65) and high (LNR 0.66-1) risk groups. Survival outcomes were estimated by the Kaplan-Meier method while the log rank test was used to assess the significance of groups compared in survival. Exploring potential variables for their independent prognostic effects were determined by Cox proportional-hazards regression model. Results : Univariate analysis indicated that high LNR, as well as the presence of lymphovascular space invasion and local recurrent tumor were correlated with poor overall survival. In contrast, tumor expression of the estrogen receptor and patients receiving anti-hormonal therapy were associated with better survival outcomes (p-values <0.05). Multivariate analysis found anti-hormonal and LNR were independent predictors
of overall survival (p-values <0.017). Conclusion : Our findings support LNR as an independent predictor of survival in node positive breast cancer.