Xerostomia-related quality of life for patients with oropharyngeal carcinoma treated with proton therapy

Purpose: We report longitudinal patient-reported quality-of-life (QoL) outcomes related to xerostomia in patients with oropharyngeal cancer treated with intensity-modulated proton therapy (IMPT). Materials and methods: Patients treated from May 2012 through December 2016 at a single institution for AJCC7 stage III-IV, M0 oropharyngeal cancer were given the 15-item Xerostomia-Related QoL Scale (XeQoLS) before, during, and for up to 2 years after treatment. We evaluated the evolution of xerostomia-related QoL over that time, and examined potential associations between those measures with clinical characteristics. Results: Sixty-nine patients had XeQoLS scores at baseline and at least once either during or after treatment. The mean (+/- SD) XeQoLS score (0-4) was 0.24 +/- 0.57 at baseline. Subsequent scores were 2.00 +/- 1.01 at 6 weeks on treatment, and 1.03 +/- 0.76, 0.97 +/- 0.78, 0.82 +/- 0.69, and 0.70 +/- 0.75 at 10 weeks, 6 months, 1 year, and 2 years after treatment, respectively. All were statistically different from baseline (p < 0.001). Univariate analyses demonstrated associations between XeQoLS score and time (p < 0.0001 for each interval), baseline XeQoLS score (p < 0.0001), stage (p = 0.008), N status (p = 0.006), and mean oral cavity dose (p = 0.038), but not for age, sex, T status, receipt of chemotherapy, smoking history, disease site, laterality of neck irradiation, mean parotid dose, or mean submandibular dose. Multivariate analysis suggested that baseline XeQoLS scores, phase of treatment, and N status were associated with XeQoLS scores measured during treatment and recovery. Conclusions: Patients receiving IMPT reported the greatest xerostomia-related QoL impairment at 6 weeks on treatment, with a 49% improvement by 10 weeks after treatment; however, XeQoLS scores remained above baseline after 2 years. As we aim to establish the value of IMPT in oropharyngeal tumors to de-intensify treatment over conventional therapy, these data help inform discussions about xerostomia-related quality of life for patients with oropharyngeal cancer treated with IMPT. (C) 2019 Elsevier B.V. All rights reserved.