Abstract: PURPOSE: The purpose of this study was to explore the best threshold of Zhengzhou University-quality of life(ZZU-QOL) scale in patients with oral cancer 3 to 6 months after operation. METHODS: A questionnaire survey was conducted on 218 patients with oral cancer who met the inclusion criteria. The patients were asked to fill in the ZZU-QOL and the University of Washington Quality of Life Scale(UWQOL). A total of 178 valid questionnaires were collected and the recovery rate was 81.65%. The UWQOL was used as "the gold standard", and the receiver operating characteristic curve (ROC) was drawn to determine the optimal threshold of quality of life scale of Zhengzhou University. Statistical analysis was performed by using SPSS 20 software package. RESULTS: There was a moderate positive correlation between total score of quality of life scale of Zhengzhou University and the total score of the UWQOL (r=0.685, P<0.05). When the ZZU-QOL threshold was 55.682, ROC curve was closest to the upper left corner, its sensitivity and specificity, false negative rate, false positive rate and Youden index were 0.797, 0.676, 0.203, 0.324 and 0.473, respectively. The area under the ROC curve was 0.809, the standard error of the area was 0.047, the 95% confidence interval was 0.718 - 0.901, and the threshold was 56 when the integer was taken. CONCLUSIONS: The optimal threshold of ZZU-QOL in oral cancer patients 3 to 6 months after operation was 56 points, which may be used as the theoretical guidance and basis for evaluation and screening of postoperative quality of life in patients with oral cancer.

Key words: Oral cancer, Quality of life, Threshold