Sensitivity and specificity of the Distress Thermometer in screening for distress in long-term nasopharyngeal cancer survivors

Background

The Distress Thermometer (dt) is a screening tool recommended to quickly identify cancer patients with distress. Our study aimed to examine the sensitivity and specificity of the dt in detecting psychological distress in long-term Chinese nasopharyngeal cancer (npc) survivors.

Methods

Data for the 442 participating npc survivors were collected through a self-administered questionnaire based on the dt and the Hospital Anxiety and Depression Scale (hads). The hads was used to define cases of psychological distress. Positive and negative groups were defined based on 4 hads criteria (Anxiety, Depression, Anxiety or Depression, and overall score). Receiver operating characteristic (roc) curves were used to examine the ability of all possible cut-off values of the dt to detect positive and negative cases. For each roc curve, the area under the curve (auc) was used as an indicator of the overall accuracy of the dt to identify positive cases of distress.

Results

The positive auc values with 95% confidence intervals (ci)] for the 4 hads criteria were 0.715 (95% ci: 0.667 to 0.764), 0.714 (95% ci: 0.661 to 0.768), 0.724 (95% ci: 0.677 to 0.771), and 0.724 (95% ci: 0.664 to 0.775) respectively. At a cut-off score of 4, the sensitivity of the dt to the four hads criteria was, respectively, 0.366 (95% ci: 0.296 to 0.436), 0.448 (95% ci: 0.364 to 0.532), 0.362 (95% ci: 0.299 to 0.425), and 0.421 (95% ci: 0.339 to 0.502), and the specificity of the dt to the 4 hads criteria was, respectively, 0.860 (95% ci: 0.818 to 0.902), 0.860 (95% ci: 0.821 to 0.899), 0.854 (95% ci: 0.814 to 0.894), and 0.854 (95% ci: 0.814 to 0.894). At a cut-off score of 5, the corresponding sensitivities were lower than those at the cut-off score of 4. All potential cut-off scores showed poor sensitivity (<0.90).

Conclusions

The roc analysis showed poor discrimination. No potential dt cut-off score had an acceptable sensitivity. The dt showed poor sensitivity in npc survivors. Thus, the dt might not be a valid scale for psychological distress screening in long-term Chinese npc survivors.