Lymph Node Ratio in Sentinel Lymph Node Biopsy Era: Are We Losing Prognostic Information?
The number of involved axillary lymph nodes (LNs) found pathologically is regarded as a significant prognostic factor in early-stage breast cancer (EBC). Recently, there is speculation that LN ratio (LNR) may be a better surrogate at predicting cancer-specific outcome than number of involved LNs. This study investigated prognostic value of LNR, using predetermined cutoff values.



Data included all women diagnosed with node-positive EBC between January 1, 2001, and December 31, 2010 (N = 553). Retrospective evaluation for clinical, demographic, and pathologic data was performed. Most had axillary node clearance (ANC) (548/553; 99.1%). Cohorts were divided by LNR risk groups (low: ≤ 0.20; intermediate: 0.21-0.65; high: >0.65). Proportional hazard modeling was undertaken to evaluate whether LNR was associated with overall survival (OS).



Median follow-up was 59.8 months. LNR distribution was as follows: low, 303/553 (54.8%); intermediate, 160/553 (28.9%); high, 90/553 (16.3%). Kaplan-Meier estimates for OS were stratified by LNR: low-risk group had better outcome for OS (P < .001). Overall 5- and 10-year OS was 63% and 58%, respectively. Number of positive LNs correlated with 10-year OS (66%, 48%, and 48% for patients with N1, N2, and N3 stage, respectively; P < .001). LNR also correlated with 5-year OS (69%, 48%, and 41% for low-, intermediate-, and high-risk groups, respectively; P < .001). Significantly, LNR on multivariate analysis also formed a prognostic model when combined with age, estrogen receptor status, PgR status and, HER2 status (P < .001).



The Findings support LNR as a predictor for OS in EBC. LNR should be considered an independent prognostic variable to current prognostic instruments already in use.
Community Oncology Department, National Cancer Control Programme (NCCP), Dublin, Ireland; Post-Graduate Department, Graduate Entry Medical School, University of Limerick, Limerick, Ireland. Electronic address: keith.quintyne@cancercontrol.ie.
Keith Ian
KI
Quintyne
Department of Medical Oncology, University Hospital Limerick, Limerick, Ireland; Stokes Institute, University of Limerick, Limerick, Ireland.
Bernie
B
Woulfe
Post-Graduate Department, Graduate Entry Medical School, University of Limerick, Limerick, Ireland; Department of Surgery, University Hospital Limerick, Limerick, Ireland.
John C
JC
Coffey
Department of Surgery, University Hospital Limerick, Limerick, Ireland.
Anne
A
Merrigan
Department of Medical Oncology, University Hospital Limerick, Limerick, Ireland; Stokes Institute, University of Limerick, Limerick, Ireland.
Rajnish K
RK
Gupta
D000328:Adult; D000367:Age Factors; D000368:Aged; D001365:Axilla; D001943:Breast Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision / Q000706:statistics & numerical data*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D000071036:Sentinel Lymph Node / Q000473:pathology*; D021701:Sentinel Lymph Node Biopsy / Q000706:statistics & numerical data*
Axillary lymph node dissection (ALND); Early-stage breast cancer (EBC); Lymph node ratio (LNR); Prognostic factor; Sentinel lymph node biopsy (SLNB)