3.3 Establishment of the LFS system based on laryngoscopic
characteristics and a comparison with other methods
According to the regression analysis, the effect of hyperemia was the
most obvious factor (OR=38.278), followed by the involvement of anterior
commissure (OR=5.314) and thick leukoplakia (OR=4.556). We established a
vocal cord LFS system with a possible range of 0-10 points (see Table 3
for details). To facilitate calculation and memorization, according to
the regression coefficient, four points were assigned to hyperemia, two
points to the involvement of anterior commissure and thickness, and one
point to two indicators (size and texture) correlated with benign and
malignant leukoplakia (Score=4×hyperemia + 2×involvement of anterior
commissure + 2×thickness + 1×size + 1×texture). The total scores of the
benign vocal cord leukoplakia group and malignant vocal cord leukoplakia
group were calculated according to the above scoring system, and the ROC
curve was generated. The area under the ROC curve (AUC) for the
diagnosis of benign and malignant vocal cord leukoplakia by the scoring
system was 0.946 (95% CI: 0.916-0.976, P =0.000). In addition,
according to the calculation formula (Score=0.060×age +2.609×texture
+1.307×hyperemia) for assessing benign and malignant vocal cord
leukoplakia reported by Fang et al .4, the AUC
was 0.880 (95% CI: 0.821-0.939, P =0.000); the AUC according to
the classification of leukoplakia reported by Zhang et
al .5 was 0.742 (95% CI: 0.664-0.820,P =0.000). The AUC of the LFS was significantly better than that
of the Fang score (P = 0.0143) and Zhang classification (P<0.0001) (Figure 1).