Skip to main content

Table 3 Dose cutpoint, sensitivity, specificity and positive likelihood ratio, positive predictive value (PPV), negative predictive value (NPV) and relative risk (RR)

From: Dose-volume relationship for laryngeal substructures and aspiration in patients with locally advanced head-and-neck cancer

  Mean dose cutpoint (cGy) Number (%) of aspirators above cutpoint (sensitivity) Number (%) of non-aspirators below cutpoint (specificity) Positive likelihood ratio: sensitivity/(100-specificity) PPV(%)a NPV(%)b RRc
Structure
 AE Folds 6500 9/10 (90.0) 13/19 (68.4) 2.81 60.0 92.9 8.4
 Arytenoids 6000 8/10 (80.0) 14/19 (73.7) 3.04 61.5 87.5 4.9
 Glossoepiglottic fold 7000 10/10 (100.0) 8/19 (42.1) 1.73 47.6 100.0 undefined
 Cricoid cartilage 6000 7/10 (70.0) 14/19 (73.7) 2.66 58.3 82.4 3.3
 Thyroid cartilage 6450 9/10 (90.0) 14/19 (73.7) 3.42 64.3 93.3 9.6
 Epiglottis 7225 7/10 (70.0) 14/19 (73.7) 2.66 58.3 82.3 3.3
 Suprahyoid epiglottis 6810 10/10 (100.0) 9/19 (47.4) 1.90 50.0 100.0 undefined
 Infrahyoid epiglottis 6300 9/10 (90.0) 12/19 (63.2) 2.45 56.3 92.3 7.3
 Total larynx 6100 9/10 (90.0) 13/19 (68.4) 2.85 60.0 92.9 8.5
 Supraglottic larynx 6650 9/10 (90.0) 13/19 (68.4) 2.85 60.0 92.9 8.5
 Subglottic larynx 5750 7/10 (70.0) 13/19 (68.4) 2.66 53.9 81.3 2.9
 Glottic larynx 6100 8/10 (80.0) 14/19 (73.7) 2.81 61.5 87.5 4.9
  1. aPPV should be greater than the a priori prevalence of aspiration which is 34.5%
  2. bNPV should be greater than the a priori prevalence of no aspiration which is 65.5%
  3. cRR is undefined if denominator is zero