Sentinel lymph node biopsy in a resourcelimited setting: a retrospective comparison of sentinel lymph node biopsy before and after the introduction of Sentimag at an academic breast unit.

Background: Sentinel lymph node biopsy (SLNB) is performed for staging and prognostication of breast cancer (BC) in cases with a clinically and radiologically negative axilla. Using blue dye and a radioactive colloid injection is considered the gold standard for SLNB. This study aims to evaluate the SLNB outcomes before and after the introduction of Sentimag at an academic breast unit. Sentimag uses an injection of superparamagnetic iron oxide which is then detected in the sentinal lymph node using a magnetometer.

Methods: A retrospective cohort study was performed comparing SLNBs done from 1 January 2017 to 31 December 2018. During 2017, a nuclear medicine technique was used for all SLNBs, while the Sentimag system was used in 2018.

Results: There was no difference between the two groups comparing age, T-stage, size of tumour, and molecular status. The only statistically significant difference found was more higher-grade tumours in the group where a nuclear medicine technique was used in 2017 (p = 0.04). There was no difference in the type of surgery performed comparing mastectomy and breast-conserving surgery rates between the two groups. There was an 11% increase in the number of patients who had an SLNB done with the Sentimag technique (2018). In 2017, 42% (58/139) had an SLNB and in 2018, 53% (59/112) had an SLNB.

Conclusion: This result demonstrates the feasibility of the magnetic technique for SLNB in a resource-limited setting. This new method shows promise as a safe and effective technique for SLNB - it is a valuable alternative in the absence of nuclear medicine (N.Med) facilities.