Elderly and Patients with Large Breast Volume Have an Increased Risk of Seroma Formation after Mastectomy—Results of the SerMa Pilot Study

SIMPLE SUMMARY: The pathophysiology behind seroma formation as a common postoperative complication after ablative procedures for breast cancer is poorly understood. Presented here is the first clinical evaluation of the SerMa (Seroma formations of the Mammary gland in breast cancer patients after mastectomy) pilot study, which investigates primarily possible immunological or inflammatory causes of seroma formation. Furthermore, clinicopathological correlations between seroma formation and tumor biology as well as lymph node involvement have been measured and showed a significant correlation with higher age and larger mastectomy specimen weight. Neither the number of lymph nodes removed or affected nor tumor biological characteristics like hormone receptor status showed a significant effect on seroma formation. ABSTRACT: The collective of the SerMa pilot study included 100 cases of primary breast cancer or Carcinoma in situ who had undergone a mastectomy procedure with or without reconstruction of the breast using an implant or expander at Augsburg University Hospital between 12/2019 and 12/2022. The study aimed to investigate possible causes of seroma formation; reported here are the clinicopathological correlations between seroma formation and tumor biology and surgical procedures. Seroma occurred significantly more often in patients with older age (median patient age in cases with seroma was 73 years vs. 52 years without seroma; p < 0.001). In addition, patients with larger mastectomy specimen were significantly more likely to develop seroma (median ablation weight in cases with seroma 580 g vs. 330 g without seroma; p < 0.001). Other significant parameters for seroma formation were BMI (p = 0.005), grading (p = 0.015) and tumor size (p = 0.036). In addition, with insertion of implant or expander, a seroma occurred significantly less frequently (p < 0.001). In a binary logistic regression, age in particular was confirmed as a significant risk factor. In contrast, tumor biological characteristics, number of lymph nodes removed or affected showed no significant effect on seroma formation. The present study shows the need for patient education about the development of seroma in particular in older patients and patients with large breast volumes within the preoperative surgical clarification. These clinicopathological data support the previously published results hypothesizing that seroma formation is related to autoimmune/inflammatory processes and will be tested on a larger collective in the planned international multicenter SerMa study.