An IMPT-IMRT Comparison of Acute Patient Reported Outcomes after Ipsilateral Radiation for Head and Neck Cancers

Abstract

Intensity modulated proton therapy (IMPT) provides superior normal tissue sparing compared to IMRT when administering ipsilateral radiation therapy (RT) for cancers of the head and neck. To determine if this dosimetric advantage translates to clinical gains, we assessed patient reported outcomes (PRO) for patients undergoing ipsilateral RT for salivary gland and tonsil cancers. PRO assessments are prospectively collected from all consenting patients undergoing RT for curative intent by department policy. Inclusion criteria for this study: completed ipsilateral RT for salivary gland or tonsil cancers between May 2015 and Dec 2017, received at least 60 Gy (RBE 1.1 for protons), and completion of the pre and post RT PRO assessments. The included assessments are the PROMIS GLOBAL 10, an overall quality of life assessment; the Was it Worth It? Questionnaire (WIWI), a patient satisfaction tool; and the EORTC QLQ-H&N35, a head and neck cancer symptom and QOL-specific scale. Outcomes after treatment were compared by modality using a Wilcoxon rank sum test. Thirty-eight patients (IMRT, n=25; IMPT, n= 13) met inclusion criteria. 8 (32%) and 5 (38%) of IMRT and IMPT patients received concomitant chemotherapy. Median dose/fraction #: 63 Gy/30, IMPT; 60 Gy/30, IMRT. Baseline PRO assessments were similar for IMRT and IMPT. At the end of treatment, IMPT was associated with significantly less mean deterioration in the following EORTC HN35 domains: pain (-5 vs -29.8, p=0.02), swallowing function (0.9 vs -23.3, p=0.02), dry mouth (-10.0 vs -46.7, p = p<0.01), sticky saliva (-13.3 vs -56.1, p<0.01), senses (-3.3 vs -44.2, p<0.01), cough (-3.3 vs -36.7, p <0.01), speech (-1.1 vs -18.9, p=0.04), feeling ill (-10.0 vs -28.3, p=0.05), social eating (-5.0 vs -26.7, p = 0.01). For patients treated without chemotherapy, the above domains all remained significant or strongly trended towards favoring IMPT, and nutritional supplementation became significant (p = 0.04). For patients with primary salivary gland cancers (n=23), pain, dry mouth, sticky saliva, senses, cough, feeling ill, social eating, and need for pain medication all significantly favored IMPT. For patients with tonsil primaries, results were underpowered to demonstrate significant differences but similar trends were appreciated. Differences in swallowing function (p=0.07), dry mouth (p=0.09), and senses (p=0.08) approached significance. No significant differences were found between modalities in the WIWI questionnaire, although 91 vs 63% of patients responded Yes to “If you had to do it over, would you choose radiation treatment again?” for IMPT vs IMRT (p=0.34). No significant differences were found in the PROMIS10 mental and physical T scores. IMPT was associated with less acute deterioration in multiple head and neck scales, but differences in global mental and physical quality of life were not detected compared with IMRT. Follow up assessments are needed to determine if these differences persist over time.