Abstract
PurposeTo identify which patient-reported outcomes (PROs) may be most improved through adaptive radiation therapy (ART) with the goal of reducing toxicity incidence among head and neck cancer patients.MethodsOne hundred fifty-five head and neck cancer patients receiving radical VMAT (chemo)radiotherapy (66-70 Gy in 30-35 fractions) completed the MD Anderson Symptom Inventory, MD Anderson Dysphagia Inventory (MDADI), and Xerostomia Questionnaire while attending routine follow-up clinics between June-October 2019. Hierarchical clustering characterized symptom endorsement. Conventional statistical approaches indicated associations between dose and commonly reported symptoms. These associations, and the potential benefit of interfractional dose corrections, were further explored via logistic regression.ResultsRadiotherapy-related symptoms were commonly reported (dry mouth, difficulty swallowing/chewing). Clustering identified three patient subgroups reporting: none/mild symptoms for most items (60.6% of patients); moderate/severe symptoms affecting some aspects of general well-being (32.9%); and moderate/severe symptom reporting for most items (6.5%). Clusters of PRO items broadly consisted of acute toxicities, general well-being, and head and neck-specific symptoms (xerostomia, dysphagia). Dose-PRO relationships were strongest between delivered pharyngeal constrictor Dmean and patient-reported dysphagia, with MDADI composite scores (mean ± SD) of 25.7 ± 18.9 for patients with Dmean <50 Gy vs. 32.4 ± 17.1 with Dmean ≥50 Gy. Based on logistic regression models, during-treatment dose corrections back to planned values may confer ≥5% decrease in the absolute risk of self-reported physical dysphagia symptoms ≥1 year post-treatment in 1.2% of patients, with a ≥5% decrease in relative risk in 23.3% of patients.ConclusionsPatient-reported dysphagia symptoms are strongly associated with delivered dose to the pharyngeal constrictor. Dysphagia-focused ART may provide the greatest toxicity benefit to head and neck cancer patients, and represent a potential new direction for ART, given that the existing ART literature has focused almost exclusively on xerostomia reduction.
Highlights
Standard-of-careradiotherapy is associated with a high toxicity burden for many locally-advanced head and neck cancer patients
MDASI-HN, MD Anderson Dysphagia Inventory (MDADI), and Xerostomia Questionnaire (XQ) results are summarized in Figure 1. 60 patients completed the patient-report outcomes (PRO) questionnaire within their first year after treatment, with the remaining 95 patients completing the questionnaire ≥1 year post-treatment (28 months, 12-74 months)
No statistically significant differences occurred in clinical parameters for other MDASIHN, MDADI or XQ responses, including HPV status and time since treatment, according to Mann-Whitney U tests and Fisher’s exact tests
Summary
Standard-of-care (chemo)radiotherapy is associated with a high toxicity burden for many locally-advanced head and neck cancer patients. Volumetric modulated arc therapy (VMAT) provides dose-sculpting capabilities to reduce incidental radiation doses to healthy tissues [2]; decreases in tumor volume [3], weight loss [4], and other inter-fractional anatomical changes common among head and neck cancer patients may reduce treatment precision and increase toxicity [5, 6]. Adaptive radiation therapy (ART) adapts a patient’s radiotherapy plan in response to inter-fractional anatomical changes to maintain target coverage and healthy tissue dose sparing objectives during the 6-7 week treatment course. Many open questions remain regarding patient selection: even in a broad sense, it is unclear which toxicity ART may most reduce
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