# Sensitivity and negative predictive value of sentinel lymph node biopsy for cutaneous melanoma for diagnosing nodal metastasis: meta-analysis of diagnostic test accuracy

## TL;DR

This study evaluates how reliable sentinel lymph node biopsy is for detecting melanoma spread, showing it is fairly accurate but has a small risk of missing cancer.

## Contribution

The study provides updated sensitivity and negative predictive value estimates for sentinel lymph node biopsy in melanoma using long-term follow-up data.

## Key findings

- The pooled sensitivity of sentinel lymph node biopsy was 0.85 (95% CI 0.80 to 0.88).
- Negative predictive value estimates ranged from 0.93 to 0.97 depending on pretest probability.
- Existing negative predictive value estimates may be positively biased.

## Abstract

Sentinel lymph node biopsy provides information about disease staging and the need for adjuvant therapy. The consequences of a false-negative result are potentially severe. The risk of a false-negative result should be quantified. The aims of this study were to estimate the sensitivity of sentinel lymph node biopsy based on studies following up patients for at least a mean or median of 5 years, appraise the risk of bias, and provide negative predictive value estimates across a range of pretest probabilities.

Ovid MEDLINE and Embase databases were searched from inception to 28 May 2025. Studies were screened independently and in duplicate, with a third author resolving conflicts. All original comparative and non-comparative English language research studies were included if the sensitivity of sentinel lymph node biopsy was calculable and participants had been followed up for a mean or median of 5 years. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Sensitivity estimates were calculated and pooled by random-effects meta-analysis. A negative predictive value curve was plotted using the pooled sensitivity estimate and a range of plausible pretest probabilities.

Fourteen studies with 8447 patients were included. The pooled sensitivity estimate was 0.85 (95% confidence interval 0.80 to 0.88). The negative predictive value estimates fell between 0.93 and 0.97, depending on pretest probability. Existing negative predictive value estimates are at risk of positive bias.

Sentinel lymph node biopsy is a sensitive test used to rule out lymph node metastasis in cutaneous melanoma. Clinicians can use negative predictive value estimates to counsel patients about the probability of false-negative results, for example, by offering reassurance to patients with thin melanomas and negative sentinel lymph node biopsy.

Sentinel lymph node biopsy (SLNB) results provide important information about the need for adjuvant therapy, and therefore the risk of a false-negative result should be quantified. A negative predictive value (NPV) curve was plotted using the pooled sensitivity estimate and a range of plausible pretest probabilities. Clinicians can use these NPV estimates to counsel patients about the probability of false-negative results, for example, by offering reassurance to patients with thin melanomas and a negative SLNB.