Is the sentinel lymph node pathology protocol in breast cancer patients associated with the risk of regional recurrence?

Background: Internationally, there is no consensus on the pathology protocol to be used to examine the sentinel lymph node (SN) in breast cancer patients. Previously, we reported that ultra-staging led to more axillary lymph node dissections (ALND). The question was, whether ultra-staging is effective in reducing the risk of regional relapse. Methods: From January 2002 to July 2003, 541 patients from 4 hospitals were prospectively registered when they underwent a SN biopsy. In hospitals A, B, and C, 3 levels of the SN were examined pathologically, whereas in hospital D at least 7 additional levels were examined. Patients with a positive SN, including isolated tumor cells, underwent an ALND. This analysis focuses on the 341 patients with a negative SN. Primary endpoint was 5-year regional recurrence rate. Results: In hospital D 34% of the patients had a negative SN as compared to 71% in hospitals A, B, and C combined (p <0.001). At 5 years follow-up, 9 (2.6%) patients had developed a regional lymph node relapse. In hospital D none of the patients had a regional recurrence, as compared to 9 (2.9%) cases of recurrence in hospitals 4, B, and C. Conclusion: The less intensified SN pathology protocol appeared to be associated with a slightly increased risk of regional recurrence. The absolute risk was still less than 3%, and does not seem to justify the intensified SN pathology protocol of hospital D.