Fewer sentinel lymph nodes up risk of false negatives in early oral cavity cancer

Sentinel lymph node biopsy (SLNB) for early oral cavity cancer is likely to yield a false negative (FN) result when the number of SLNs is small, a recent study has found.

“Careful postoperative monitoring for neck recurrence is needed in patients with one to two identified SLNs … and elective dissection may be considered in patients with just a single identified SLN,” the researchers said.

The study included 131 patients (median age 63 years, 66.4 percent men) who underwent SLNB between 2011 and 2016. The median number of SLNs identified was three, with an identification rate of 100 percent. The rate of positive SLNs increased with increasing SLNs identified, though the link only reached borderline significance (p=0.057).

Meanwhile, seven negative SLNs were deemed to be FN; in six of these cases, only 1–2 SLNs were identified during the procedure, and only one case had ≥3 SLNs identified (p=0.013).

Multivariable logistic regression analysis confirmed that relative to identifying only 1–2 SLNs, detecting ≥3 SLNs was associated with a significantly lower likelihood of FN (odds ratio, 0.03, 95 percent confidence interval, 0.00–0.75; p=0.033). Other potential correlates, such as patient age and sex, primary tumour site, tumour stage, and imaging techniques used did not affect the odds of FN.

Important study limitations included its small sample size, as well as the variance in the equipment and surgeon experience levels. Future studies should seek to standardize procedures and patient assessment methods, the researchers said.