Lymph Node Involvement and Related Risk Factors in Patients With Breast Cancer Referred for Radiotherapy: A 20-Year Study on 15000 Women

Objectives: Tumor size and axillary lymph node (LN) involvement are used as prognostic markers and a guide for choosing adjuvant therapy. This study aimed to evaluate LN involvement and related risk factors in patients with breast cancer (BC) referred for radiotherapy. Materials and Methods: Using the census sampling method, 15,000 women with BC referring for radiotherapy were enrolled in this retrospective descriptive study performed at Tabriz University of Medical Sciences during 2000-2020. LN involvement and related risk factors were recorded and analyzed using the t test and ANOVA test at a significance level of P<0.05. Results: The prevalence of LN involvement in this study was 25%. The estrogen receptor status and LN involvement were associated with metastasis. The odds ratio of metastasis in patients with a negative estrogen receptor was about twice that of women with estrogen receptor positivity. Finally, the risk of metastasis in patients presenting with LN involvement was eight times higher than that of patients without LN involvement. Conclusion: In general, estrogen receptor status and LN involvement were associated with metastasis in patients with BC. Thus, these factors can be regarded as a guide to start necessary interventions earlier in at-risk patients.