Immunohistochemical and Clinicopathological Factors Associated with Axillary Lymph Node Metastasis in Breast Cancer Patients of Northern Pakistan

Background: Breast cancer is the most common type of tumors in Pakistani women, with axillary lymph node (ALN) positivity reported to be one of the most important prognostic factors. This study shows the distribution of various clinical and pathological variables including age, tumor size, grade, histologic subtype, and hormone receptor status among Pakistani women with and without ALN metastasis. Materials and Methods: A total of 245 cases of primary breast cancer from Northern Pakistan were analyzed in this study. Their clinical, pathological and immunohistochemical parameters, including estrogen receptor (ER), progesterone receptor (PR) and Her-2/Neu status, were extracted from previous histopathological reports and stratified based on the occurrence of ALN metastasis. Results: Occurrence of ALN metastasis was significantly different between older age patients above 50 years and younger age patients age 5cm in size (80%, n=60), [ χ² (2, N=245) =23.1, p<0.001] and tumors with higher nuclear grade III (78.4%, n=40), [ χ² (1, N=245) =5.1, p=0.02] . ALN metastasis was inversely associated with expression of estrogen receptor [ χ² (1, N=245) =12.5, p<0.001] , and progesterone receptor [ χ² (1, N=245) = <0.001 , p=0.99] , while it was directly associated with Her-2/Neu expression [ χ² (1, N=245) = 5.63 , p=0.01] . Conclusion: In Pakistani women ALN metastasis was significantly associated with older age, tumor size, and high grade tumors showing Her2/Neu expression, and was inversely associated with ER, PR expression in breast tumors.  Key Words: Axillary lymph node, Estrogen receptor, Immunohistochemistry, Progesterone receptor, Northern Pakistan.