borderline significanceP = 0.07
Although the patients’ age attained borderline significance (adjusted RR 1.02 / year (95% CI: 0.998–1.034; P = 0.07)), head or neck location of the primary tumor (adjusted RR 2.2 (95% CI: 1.004–4.799; P = 0.48)) and a decreasing number of excised SLNs (adjusted RR 0.60 per SLN (95% CI: 0.417–0.874; P = 0.007)) turned out to be independent factors predicting false-negative results of SLNB.