A Principal Component of Quality of Life Measures Is Associated with Survival for Head and Neck Cancer Patients Treated with Radiation Therapy

SIMPLE SUMMARY: Health-related quality of life (HRQOL) surveys describe the patient experience of disease and treatment. The relationship between post-treatment recovery of HRQOL and outcome in head and neck cancer is not well characterized. Impaired recovery of numerous individual components of HRQOL were associated with increased mortality. To obtain a better understanding how HRQOL (as a whole) impacts survival, we utilized a statistical technique called principal component analysis (PCA). PCA generated a total score of several HRQOL domains, named principal component 1 (PC1), to more accurately describe the cumulative impact of poor HRQOL recovery on outcome. PC1 was associated with survival and may be a useful tool in future studies to identify at-risk patients. ABSTRACT: Background: Health-related quality of life (HRQOL) metrics can be associated with survival in head and neck cancer (HNC); however, the impact of HRQOL recovery and the relevant HRQOL domains regarding outcome are unclear. Methods: Using a single-institution database, we retrospectively reviewed HNC patients treated with definitive or postoperative radiation therapy between 2013 and 2018. The recovery of individual HRQOL domains were determined by the ratio of the post-treatment to baseline scores. Univariate and Multivariate Cox regression were used to analyze survival outcomes. Principal component analysis was used to adjust for multicollinearity of HRQOL domains. Results: In 218 HNC patients who received radiation therapy, median follow-up was 24.8 months (interquartile range (IQR) 14.5–32.0). Principal component analysis evaluating the recovery of HRQOL domains revealed two independent principal components (PC), PC1 and PC2. PC1, which received contributions from the functional domains; physical (PF), role (RF), emotional (EF), cognitive (CF), and global health status (GQOL) was significantly associated with disease-free (HR = 0.77, 95% CI 0.61–0.98, p = 0.034) and overall survival (HR = 0.76, 95% CI 0.65–0.91, p = 0.004) on multivariate analysis and PC2, had no correlation with outcome and was mainly represented by social functioning. Unplanned hospitalization was significantly associated with lower PC1 scores (β = −0.997, Std. Error = 0.244, p < 0.001). Conclusion: Our study provides evidence that post-treatment recovery of HRQOL domains were associated with overall survival (OS) in HNC. PC1 is an attractive clinical tool to assess the recovery across multiple different HRQOL and the relationship with survival. Future prospective studies may identify patients who could benefit from additional rehabilitation based on PC1 score.