Sentinel node biopsy as a practical alternative to axillary lymph node dissection in breast cancer patients:: An approach to its validity

Background: Sentinel node biopsy (SNB) has been proposed as an alternative to axillary lymph-node dissection (ALND) in breast cancer. Before implementing SNB in our practice, we wished to test its validity by comparing it to the standard ALND, both in our hands and with other reported series. Patients and methods: One hundred thirty-two patients were included prospectively. SNB and immediate ALND were performed. For SNB, a technetium-colloid was used to produce preoperative lymphoscintigraphy and intraoperative gamma-probe search for the SN. Serial sectioning and immunostains were used on the SN. A comprehensive review of the literature was done in order to run a meta-analysis of diagnostic tests using a summary receiver operating characteristic curve (SROC) to calculate the pooled parameters of sensitivity and associated 95% confidence interval (95% CI), including our own data. Results: Our technical success rate was 96%. Local sensitivity was 96%, with a 95% CI from 85%-99%. Seven patients were upstaged by the SNB. A literature search identified 18 studies published from 1996-1999. Estimates of sensitivity ranged from 83%-100%. The pooled data meta-analysis gave a global sensitivity of 91%, with a 95% CI from 89%-93%. The area under the global SROC curve was 0.9967. Conclusions: The minimally invasive SNB was shown to be a practical alternative to ALND. We propose to use local as well as global sensitivity and associated 95% CI to test the validity of SNB in the clinical setting. Due to limitations of ALND as the golden standard, SNB can in fact be considered a more accurate method for nodal staging.