Prospective functional outcomes in sequential population based cohorts of stage III/ IV oropharyngeal carcinoma patients treated with 3D conformal vs. intensity modulated radiotherapy

Abstract

Background and purpose: To compare early (3 and 6 month) and later (12 and 24 month) functional outcomes of stage III and IV (M0) oropharyngeal squamous cancer patients treated in sequential cohorts with 3D conformal (3DCRT) or intensity modulated radiotherapy (IMRT). Patients and methods: 200 patients in sequential population based cohorts of 83 and 117 patients treated at a single institution with 3DCRT and then IMRT respectively were prospectively assessed at pre-treatment and 3, 6, 12 and 24 months post treatment. A standard functional outcomes protocol including performance status (KPS, ECOG), 3 Performance Status scales for Head and Neck (PSS-HN), the Royal Brisbane Hospital Outcome Measure for Swallowing (RBHOMS), Voice Handicap Index-10 (VHI-10) and self-rated xerostomia were applied. Results: Mean age at diagnosis was 59 years. The primary site was base of tongue in 77 and tonsil or soft palate in 123 patients. Median follow up was 2.5 years for the second cohort. Concomitant therapy was used in 159 (79.5%). Overall survival at 3 years was 75.6% and 71.5% for IMRT and 3DCRT cohorts respectively (not significant). A multiple imputation technique was used to estimate missing values in order to avoid a healthy patient bias. KPS and ECOG reached nadirs at 3 to 6 months but approached baseline values at 12 to 24 months and did not differ by treatment. The 3 PSS-HN scales, Eating in Public (p < 0.001), Understandability of Speech (p = 0.009) and Oral Diet Texture (p = 0.002) and all showed significantly better outcomes in favor of IMRT. The RBHOMS showed a difference in favor of IMRT which appeared during 3 to 6 months (p < 0.001). The VHI-10 also showed a difference in favor of IMRT (p = 0.015). Self-rated xerostomia did not differ at 3 and 6 months but was significantly better in favor of IMRT after 12 months p = 0.005 Conclusions: A prospectively administered functional outcomes protocol showed meaningful differences in favor of IMRT over 3DCRT early (3-6 months) and later (12-24 months) in the treatment of oropharyngeal carcinoma with equivalent survival. These data support the adoption of IMRT as the standard radiation treatment method for patients with stage III and IV (M0) oropharyngeal squamous carcinoma. KPS and ECOG may not be sensitive to oropharyngeal cancer patients' functional outcomes by treatment.