Abstract P1-01-31: Axillary Recurrence Rate Is Associated with Sentinel Lymph Node Pathology Protocol

Abstract

Abstract Background Internationally, there is no consensus on the pathology protocol to be used to examine the sentinel lymph node (SN). At present, therefore, various hospitals use different SN pathology protocols, leading to different SN findings and subsequent surgical treatment strategies. Previously, we reported in a prospective registry study of 4 hospitals in the Netherlands, that ultra-staging led to more axillary lymph node dissections (ALND) (Bolster et al. Ann Surg Oncol 2006). This present study reports follow-up data of the patients who had a negative SN, so patients who did not undergo an additional ALND. The question was, whether ultra-staging and thus fewer patients not undergoing an additional ALND, is effective in that it reduces the risk of relapse. Patients and Methods Patients from 4 hospitals (A, B, C, and D) were prospectively registered when they underwent a SN biopsy because of a cytological or histological proven invasive breast cancer. 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. In the absence of apparent metastases with H&E examination, immunohistochemical examination was performed in all 4 hospitals. Patients with a positive SN, including isolated tumor cells, underwent an ALND. This analysis focuses on the SN negative patients, who did not undergo a completion ALND. In all cases a follow-up period of at least 5 years was guaranteed. Primary endpoint was 5-year regional recurrence rate. Results Of 541 patients who underwent a SN procedure, 341 (63%) patients had a negative SN, and did not undergo an ALND. In hospital D fewer patients had a negative SN when compared to patients in hospitals A, B, and C (34% versus 71%, P<0.001). At 5 years follow-up, 9 (2.6%) patients showed a regional lymph node relapse. Five (1.5%) patients had an axillary lymph node recurrence and 4 (1.2%) patients a supraclavicular recurrence. In hospital D none of the patients had a regional recurrence, as compared to 9 (2.9%) cases of recurrence in hospitals A, B, and C. Conclusion We showed that patients who underwent a less intensified SN pathology protocol, with a reduced performance of ALND, had a slightly increased risk of recurrence. However, whether this justifies 37 additional lymph node dissections per every 100 patients can be questioned. Therefore, a SN pathology protocol as is used in most centers nowadays, with on average 3 levels per node, seems to be adequate. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-31.