Revisiting Rotter's Lymph Nodes: Insights from Axillary Clearance Surgery at a Tertiary Care Hospital from India

Interpectoral lymph nodes (IPNs), or Rotter's lymph nodes, are a critical yet understudied component of breast cancer lymphatic drainage, with potential implications for staging and therapeutic outcomes. Despite their role in "skip metastases," clinical guidelines remain ambiguous regarding IPN dissection due to conflicting evidence on their metastatic rates and associated surgical risks. This study aims to address gaps in population-specific data, particularly in India, where breast cancer burden is high, and modified radical mastectomy (MRM) is prevalent. This study sought to quantify IPN metastasis rates in Indian breast cancer patients, identify clinicopathological predictors of IPN involvement, and propose evidence-based criteria for selective IPN dissection to balance oncologic efficacy and surgical morbidity. A retrospective analysis of 472 breast cancer patients (2017-2024) undergoing axillary lymph node dissection (ALND) with mastectomy/lumpectomy was conducted. IPNs were dissected separately and examined pathologically. Clinicopathological variables, including tumor size, nodal status, extranodal extension (ENE), and molecular subtypes, were analyzed. Univariate and multivariate logistic regression identified predictors of IPN occurrence and metastasis. IPNs were detected in 9.1% (43/472) of patients, with metastasis in 3.47% (16/460) of the total node positive cases. No isolated IPN metastases (without axillary involvement) were observed. Advanced nodal disease (pN3: OR = 3.78, *p* < 0.001), ENE (OR = 2.15, *p* = 0.012), and pathological Stage III (OR = 2.95, *p* < 0.001) independently predicted IPN occurrence. IPN metastasis correlated strongly with ENE (OR = 3.4, *p* = 0.005), pN2/N3 stage (OR = 4.8, *p* < 0.001), and larger metastatic nodal size (*p* = 0.002). No associations were found with molecular subtypes or tumor location. IPN metastasis is rare in early-stage (pN0/pN1) disease but increases significantly with advanced nodal burden. Selective IPN dissection in high-risk patients (pN2/pN3, ENE) may optimize staging accuracy while minimizing unnecessary morbidity. These findings support a risk-stratified approach to IPN evaluation in resource-variable settings. Further prospective studies are needed to validate long-term oncologic outcomes.