ORIGINAL ARTICLE Impact of xerostomia on dysphagia after chemotherapy–intensity-modulated radiotherapy for oropharyngeal cancer: Prospective longitudinal study Jeffrey M. Vainshtein, MD, 1† Stuart Samuels, MD, PhD, 1 Yebin Tao, MSc, 2 Teresa Lyden, MA, CCC-SLP, 3 Marc Haxer, MA, CCC-SLP, 3 Matthew Spector, MD, 4 Matthew Schipper, PhD, 1,2 Avraham Eisbruch, MD 1 * 1 Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, 2 Department of Biostatistics, University of Michigan, Ann Arbor, Michigan, 3 Department of Speech Pathology, University of Michigan, Ann Arbor, Michigan, 4 Department of Otolaryngology, University of Michigan, Ann Arbor, Michigan. Accepted 13 September 2015 Published online 25 November 2015 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/hed.24286 ABSTRACT: Background. The purpose of this study was to assess how xerostomia affects dysphagia. Methods. Prospective longitudinal studies of 93 patients with oropharyn- geal cancer treated with definitive chemotherapy–intensity-modulated radiotherapy (IMRT). Observer-rated dysphagia (ORD), patient-reported dysphagia (PRD), and patient-reported xerostomia (PRX) assessment of the swallowing mechanics by videofluoroscopy (videofluoroscopy score), and salivary flow rates, were prospectively assessed from pretherapy through 2 years. Results. ORD grades 2 were rare and therefore not modeled. Of patients with no/mild videofluoroscopy abnormalities, a substantial pro- portion had PRD that peaked 3 months posttherapy and subsequently improved. Through 2 years, highly significant correlations were observed between PRX and PRD scores for all patients, including those with no/ mild videofluoroscopy abnormalities. Both PRX and videofluoroscopy scores were highly significantly associated with PRD. On multivariate analysis, PRX score was a stronger predictor of PRD than the video- fluoroscopy score. Conclusion. Xerostomia contributes significantly to PRD. Efforts to further decrease xerostomia, in addition to sparing parotid glands, may translate into improvements in PRD. V C 2015 Wiley Periodicals, Inc. Head Neck 38: E1605–E1612, 2016 KEY WORDS: xerostomia, dysphagia, head neck cancer, patient- reported outcomes, intensity-modulated radiotherapy (IMRT) INTRODUCTION Patients with oropharyngeal cancer, the majority of whom have human papillomavirus-related (HPV-positive) oro- pharyngeal cancer, have excellent oncologic outcomes after chemoradiotherapy (CRT), which makes the preven- tion of radiation-related toxicities a priority. 1 Dysphagia is a common sequel of CRT for head and neck cancer and a major determinant of patient-reported quality of life (QOL). 2,3 Previous studies have demonstrated that CRT can affect the mechanics of swallowing, resulting in increased bolus transit time, decreased movement of the tongue base toward the posterior pharyngeal wall, reduced laryngeal elevation, and food retention in the oral cav- ity. 4,5 These changes are uncomfortable and place patients at risk for aspiration-related complications. 6 Despite aggressive management of dysphagia with rehabilitation and exercise regimens, many patients do not regain their pretreatment swallowing function, and some may require prolonged feeding tubes for nutritional support. 4,7 Efforts to characterize the functional anatomy of swallowing using videofluoroscopy have identified organs at risk for CRT, including pharyngeal constrictors, glottis, supraglot- tic larynx, and upper esophagus. 5,8,9 We have previously reported our institutional experience with definitive organ-sparing CRT for oropharyngeal cancer, demonstrat- ing that dysphagia and its complications are reduced by limiting the dose to the swallowing-related organs using intensity-modulated radiotherapy (IMRT). 3,8,10–12 Despite use of swallowing organ-sparing IMRT, many patients still complain of difficulty swallowing dry foods. There is evidence that patient-reported dysphagia (PRD) often does not correlate with objective measures of dys- phagia (ie, the feeling of difficulty swallowing may not relate to the dysfunction of the swallowing struc- tures). 13–15 This disparity implies that other factors related to eating, not involving dysfunction of the swallowing structures, may be responsible for the sensation of dyspha- gia. Indeed, xerostomia, another common consequence of head and neck radiotherapy (RT), can make swallowing, especially dry food, difficult to the point where patients require excessive water or simply avoid such foods. 16,17 Although parotid gland-sparing with IMRT in recent years has decreased xerostomia rates, approximately 25% to *Corresponding author: A. Eisbruch, Department of Radiation Oncology, University of Michigan Hospital, 1500 E. Medical Center Drive, Ann Arbor MI 48109. E-mail eisbruch@umich.edu † Current address: Department of Radiation Oncology, Winship Cancer Insti- tute, Emory University School of Medicine, Atlanta, Georgia Contract grant sponsor: Supported in part by National Institutes of Health (NIH) grant PO1 CA59827 and the Newman Family Foundation. This work was presented at the 56th Annual Meeting of American Society for Radiation Oncology (ASTRO), San Francisco, CA, September 14–16, 2014. HEAD & NECK—DOI 10.1002/HED APRIL 2016 E1605