Abstract P3-03-10: Pre-operative lymphoscintigraphy for sentinel lymph node localisation: Is it necessary?

Abstract

Abstract Introduction Sentinel lymph node biopsy (SLNB) has replaced lymph node clearance for staging of the axilla in patients with early invasive breast cancer and no evidence of lymph node involvement on ultrasound or needle biopsy. It is recommended that a dual technique, using isotope and blue dye, is used to locate the sentinel lymph node (SLN) intra-operatively. Often, at the time of radioisotope injection, a lymphoscintigram (nuclear medicine scan) is obtained to demonstrate the 'hot' sentinel lymph node with or without skin marking of its anatomical position. Performing a lymphoscintigram adds time and cost to the localisation process. In our centre, this investigation costs £899-999 (˜US $1180-1300). Aims The aim of this study is to find out whether obtaining a pre-operative lymphoscintigram aids the surgeon in the localisation of the SLN or affects the number of sentinel lymph nodes biopsied in the axillary staging of patients with early invasive breast cancer. Methods We carried out a retrospective study of patients who underwent SLNB for breast cancer in our hospital Trust between March 2012 and November 2017. We identified those patients who had a lymphoscintigram performed pre-operatively for SLN localisation. We recorded the number of SLNs identified on imaging and compared this with the number of SLNs biopsied during the operation. Results 349 patients underwent 354 SLNBs during the study period. One patient was male, the remainders were female. The mean age of patients was 57.2 years (range 25 to 98 years). In 295 (83.3%) cases, a lymphoscintigram was obtained prior to SLNB for node localisation, and 268 (90.8%) of these scans were able to identify one or more SLNs. In 173 (58.6%) scans, a single SLN was identified. In 27 (9.1%) scans it was either unclear how many SLNs were demonstrated or no SLNs were seen (16/295 no SLN identified, 11/295 unclear how many SLNs). In 102 (34.6%) cases, the number of SLNs biopsied matched the number of SLNs identified on imaging. Of those that did not match, 76.2% had more and 15.0% fewer SLNs excised than shown on imaging. In 8.8% it was unknown if the number of SLNs matched that seen on imaging due to lack of histopathology results. Conclusion Lymphoscintigraphy for SLN localisation is costly and time consuming. In a high proportion of cases, number of SLNs identified on imaging does not match the number biopsied and thus, we suggest, that it is not required prior to SLNB and should be removed from practice. Citation Format: Clark SL, Yilmaz D, Arun K, Javadzadeh S, Saeed S, Ullah MZ. Pre-operative lymphoscintigraphy for sentinel lymph node localisation: Is it necessary? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-10.