What Should We Know in Postoperative Surveillance Imaging After Oncoplastic Breast-Conserving Surgery with Pellet-Type Acellular Dermal Matrix?

Rationale and Objectives: The aim of this study was to evaluate the usual postoperative imaging findings among patients who underwent oncoplastic breast-conserving surgery (BCS) with acellular dermal matrix (ADM) and to assess the clinical utility of mammography (MG) and ultrasonography (US) in follow-ups. Materials and Methods: This retrospective review of our prospectively collected database of patients who underwent oncoplastic BCS with ADM was conducted with IRB approval and in HIPPA compliance. A total of 105 patients whose follow-up MG and US studies over 2 years after surgery were available were included in this study. Postoperative imaging findings were analyzed based on sequential MG and US follow-ups. The clinical outcomes and pathological data were also reviewed. The diagnostic performance of MG and US for postoperative surveillance was assessed. Results: On MG, ADM presented as an oval (99/105, 94.3%), circumscribed/obscured (65/105, 61.9%), and high-density (56/105, 53.3%) mass with calcifications (54/105, 51.4%). On US, the ADM-filled cavity presented as an oval (93/105, 88.6%), circumscribed (70/105, 66.7%), heterogenous echoic (65/105, 61.9%) mass with marginal/posterior acoustic shadowing (95/105, 90.5%) on US. During the follow-up period (mean, 46.1 months; range, 26-58 months), four tumor recurrences were diagnosed (4/105, 3.8%). One tumor recurrence detected on MG presented as microcalcifications (1/4, 25%), which were differentiated from benign postoperative calcifications due to their suspicious morphology and location. Two additional recurrences (2/4, 50%), which were MG-negative small masses or intraductal lesions, were detected on US. One tumor recurrence was missed on both MG+US and was detected by magnetic resonance imaging performed at clinician's request. The sensitivity and specificity of MG, US, and MG+US for postoperative surveillance were 25%, 50% and 75% and 100%, 98% and 98%, respectively. Conclusion: Recognition and adequate interpretation of the usual findings after oncoplastic BCS with ADM insertion are important in postoperative imaging surveillance. The sole use of MG is not sufficient for the detection of mass-type tumor recurrence due to the density of inserted ADM fillers. Therefore, the combined use of MG+US could serve as a useful postoperative surveillance tool with increased sensitivity in this population.