EP.TH.322Should a concurrent sentinel node biopsy be performed when the preoperative histopathological category of B5c in a breast cancer biopsy is identified?

Aim To assess the management of sentinel lymph node biopsy (SLNB) in patients with a pre-operative B5c histopathological diagnosis. Method A retrospective study of the decision for SLNB in 31 breast cancer patients with B5c biopsy and their final histology were reviewed between 2009-2019. Factors that determine concurrent SLNB (size of mass lesion > 1cm/increasing size, DCIS > 4cm, recurrence and abnormal lymph nodes on ultrasound) were assessed. Results 15 patients (48%) with invasive disease and 7 patients (23%) with non-invasive disease had concurrent SLNB, whilst 9 (29%) patients with non-invasive disease did not receive concurrent SLNB and no patient (0%) with invasive disease failed to receive concurrent SLNB. Using the above inclusion and exclusion criteria 21 of 31 (68%) patients would have been managed correctly whilst 5 (16%) would of had unnecessary surgery and 5 (16%) would have required a second operation. Discussion In this study, 48% of patients with concurrent SLNB were identified as invasive and avoided a second operation. Although 23% of patients underwent unnecessary SNLB, no invasive disease SLNBs were missed. Solely using inclusion and exclusion criteria would not have improved results. This suggests that there must be other factors involved in correctly managing these patients. Conclusion Discussions with the patient about risk benefits of SLN complications vs repeat surgery, and patient comorbidity, in addition to radiological characteristics, may assist management decisions.