Implicaciones de la biopsia selectiva de ganglio centinela en cadena mamaria interna sobre la radioterapia adyuvante en mujeres con cáncer de mama sin invasión axilar

Abstract

ObjectiveTo determine the role of internal mammary sentinel lymph node (IM-SLN) biopsy in adjuvant radiotherapy in female patients with early-stage breast cancer when axillary lymph node biopsy is not performed. Patients and methodsRetrospective cohort study of female patients with early-stage breast cancer diagnosed between January 2008 and December 2016. Only patients with an indication for SLN biopsy and migration of the radiotracer into the internal mammary nodes were included. Data were recorded and analysed on the patients’ clinical features, tumour histology, surgical treatment, adjuvant treatment, locoregional recurrence and overall survival. ResultsA total of 2,622 invasive breast carcinomas were diagnosed. Twenty-three (2.2%) patients had exclusive drainage to the internal mammary nodes. IM-SLN was detected in 65.2% (15/23) of patients, with a mean of 1.61 nodes harvested per patient. Seventy-five per cent of patients receiving adjuvant radiation therapy received it on the internal mammary chain. Chemotherapy and endocrine therapy were administered to 52.2% (12/23) and 87% (20/23) of patients, respectively. A statistically significant association was found between IM-SLN identification and radiotherapy to the internal mammary chain (P<.003), as well as between IM-SLN involvement and radiotherapy to the internal mammary chain (P<.006). One patient developed breast cancer recurrence and another patient developed bone metastases. The median follow-up was 60 months. No deaths were reported. ConclusionsBoth IM-SLN identification and involvement modify the rate of radiotherapy to the internal mammary chain in patients with early-stage breast cancer.