Sentinel Lymph Node Biopsy in Pregnant Women with Breast Cancer

Sentinel lymph node biopsy (SNB) in pregnant women with breast cancer is uncommonly pursued given concern for fetal harm. This study evaluated efficacy and safety outcomes in pregnant breast cancer patients undergoing SNB. Patients who underwent SNB while pregnant were identified from a retrospective parent cohort of women diagnosed with breast cancer during pregnancy. Chart review was performed to tabulate patient/tumor characteristics, method/outcome of SNB, and short-term maternal/fetal outcomes. Within a cohort of 81, 47 clinically node-negative patients had surgery while pregnant: 25 (53.2 %) SNB, 20 (42.6 %) upfront axillary lymph node dissection, and 2 (4.3 %) no lymph node surgery. Of SNB patients, 8, 9, and 8 had SNB in the first, second, and third trimesters, respectively. 99 m-Technetium (99-Tc) alone was used in 16 patients, methylene blue dye alone in 7 patients, and 2 patients had unknown mapping method. Mapping was successful in all patients. There were no SNB-associated complications. At a median of 2.5 years from diagnosis, there was one locoregional recurrence, one new primary contralateral tumor, three distant recurrences, and one breast cancer death. Among patients who underwent SNB, there were 25 liveborn infants, of whom 24 were healthy, and 1 had cleft palate (in the setting of other maternal risk factors). SNB in pregnant breast cancer patients appears to be safe and accurate using either methylene blue or 99-Tc. This is one of the largest reported experiences of SNB during pregnancy; however, numbers remain limited. SNB rates in this cohort were lower than in non-pregnant breast cancer patients.