Challenging the 20% Rule: Is a Fixed Cutoff Still Appropriate for Elective Neck Dissection in cN0 Necks?

BACKGROUND

The 20% occult metastasis threshold proposed by Weiss in 1990 has long guided elective neck dissection (END) in clinically node-negative (cN0) head and neck cancer, despite advances in surgical safety and oncologic evidence.

METHODS

An international web-based cross-sectional survey evaluated acceptable risk thresholds and attitudes toward END among head and neck (HN) surgeons, other healthcare professionals, and non-healthcare participants. The primary outcome was the acceptable occult metastasis risk to justify END; secondary outcomes included acceptable 5-year mortality increase and complication trade-offs.

RESULTS

Of 2077 responses, 2008 were analyzed. Overall, 55% would undergo END at ≤ 10% occult metastasis risk and 86% at 20%. Responses differed significantly across groups (p < 0.0001), with lower thresholds among HN surgeons; 57% endorsed END at ≤ 10% and 92% at ≤ 20%. Among HN surgeons, a threshold of 5% or lower was considered sufficient to include the following levels in the dissection: 78% of surgeons for Level IIB, 75% for Level IV, and 69% for Level V. The majority of HN surgeons (90%) considered it more appropriate to calculate the individual risk and discuss the indication with the patient rather than relying on a fixed threshold.

CONCLUSIONS

Most respondents-particularly HN surgeons-favor lower thresholds than the historical 20%, supporting individualized risk-based decision-making rather than reliance on a fixed cut-off.