Lymph node ratio, number of excised nodes and sentinel-node concepts in breast cancer

Abstract

We read with great interest the review by Pepels et al. [1] on the safety of withholding axillary lymph node dissection (ALND) to the patients with clinically node-negative breast cancer. According to the survival and local control results from the NSABP B-32 randomised phase 3 trial [2] the authors concluded that in the patients with T1 or small T2 sentinel node (SN)-negative breast cancer omission of ALND can be regarded as safe. They pointed out that there is a shift toward omitting completion ALND in SN-positive patients but estimated that in SN-positive series the overall axillary recurrence rates were 2.8 times higher than for the SN-negative studies, and axillary recurrence rates after 5 and 8 years might be as high as 13 and 18%, respectively. They highlighted that in many patients with a positive SN withholding ALND may be not safe and that the role of systemic therapy have to be elucidated to establish a potential role for avoiding ALND in selected SN-positive cases. Most of published studies on SN associated with ALND reported not insignificant prevalence of false-negative results, but the clinical consequences of these false-negative SN were fewer than expected. The discrepancy between prevalence of false-negative SN and lower prevalence of nodal recurrence in patients without definitive axillary treatment, the discrepancy between prevalence of axillary failure in clinically node-negative patients who do not undergo ALND and prevalence of positive nodes in clinically node-negative patients undergoing ALND have been partly attributed to the systemic therapies which are administered to the most SN-negative patients [3–5]. In contemporary practice of breast cancer treatment on the one hand there is a shift toward using systemic therapies as a substitute for potentially incomplete surgery (i.e., SN biopsy alone in SN-positive cases) more than as a complement to complete surgery. On the other hand, ratio of involved to total number of LNs (LNR) was found to be a better prognostic factor than the number of positive lymph nodes (LNs) for staging node-positive breast cancer in series of patients treated in era of systemic therapy [6–8]. An association between survival and extension of nodal dissection evaluated by the total number of the removed LNs, the number of removed uninvolved LNs, LNR with improvement in outcome in cases of more extended lymphadenectomy has been reported for melanoma and for colon, lung, gastric, pancreatic, esophageal, and breast cancers. LNR can minimize the stage migration produced by extended nodal dissection; using LNR rather than the absolute number of positive nodes reduces inter-institutional differences in outcome that may exist because of variations in the number of nodes excised. However, the best cut-off points of LN ratio required for a staging classification of each malignant tumor is controversial. Better prognosis has been reported with higher number of dissected normal nodes in histologically node-positive and -negative gastrointestinal tumors and several studies on breast cancer showed survival advantages after removal of many axillary nodes even if all regional nodes were pathologically negative [4, 9]. Although the Will Rogers effect N. Peparini P. Chirletti Department of General Surgery ‘‘Francesco Durante’’, La Sapienza University, Viale del Policlinico, 155, 00161 Rome, Italy