Postoperative Chylous Leakage in Breast Cancer Patients: A Multicentre Case Series.

Introduction: Chylous leakage is a rare complication following breast cancer surgery, characterized by milky, lipid-rich fluid collection in surgical drains. While well documented in thoracic and abdominal surgeries, its occurrence after breast procedures remains poorly understood with limited literature. This study evaluates the incidence, characteristics, and management of this complication. Methods: A retrospective analysis was conducted, and seven patients with confirmed chyle leakage were identified among 1,441 breast cancer patients who underwent breast cancer surgery at two Hong Kong surgical centres within a 5-year period. Patients with prolonged drainage or milky fluid underwent laboratory analysis to confirm chylous leakage. Demographics, tumour characteristics, surgical details, management strategies, and outcomes were analysed. Results: Seven patients (0.49%) developed chylous leakage. The median age was 67 years, and the median BMI was 22.2 kg/m2. Four patients had right-sided, and three had left-sided breast cancer. Most tumours (85.7%) were located in the upper outer quadrant. All patients underwent mastectomy with various axillary procedures. Chylous drainage was identified between postoperative days 2 and 15 in 6 patients, with 1 late presentation at 6 months. Six patients (85.7%) were successfully managed with dietary modifications (medium-chain triglyceride or low-fat diet), with resolution within 3-11 days. One patient with late presentation required surgical intervention as definitive treatment. No recurrences or delays in adjuvant therapy occurred. Conclusion: Chylous leakage after breast cancer surgery can occur on either side and can occur in patient with sentinel lymph node biopsy. Conservative management with dietary modification is highly effective as first-line treatment. This study highlights the need for increased awareness of this complication and provides foundation for further investigation into its incidence, pathophysiology, and optimal management.