A Comparison of Outcomes Using Intensity-Modulated Radiation Therapy and 3-Dimensional Conformal Radiation Therapy in Treatment of Oropharyngeal Cancer

Abstract

Approximately 50% of head and neck cancer survivors experience dysphagia and related morbidity. Intensity-modulated radiation therapy (IMRT) is increasingly used to treat oropharyngeal cancers with excellent oncologic outcomes, but few studies have compared it with conventional 3-dimensional conformal radiation therapy (3D-CRT) to determine whether it can decrease treatment-related toxic and adverse effects. To determine whether IMRT improves percutaneous endoscopic gastrostomy (PEG) tube and treatment-related toxicity outcomes compared with 3D-CRT in patients with oropharyngeal squamous cell carcinoma. Retrospective review of 159 patients with oropharyngeal primary tumors with no history of chemotherapy, radiation therapy, or surgery of the head and neck who underwent definitive treatment with radiotherapy for oropharyngeal squamous cell carcinoma at the Hollings Cancer Center outpatient clinic, Medical University of South Carolina, from 2000 to 2009. Doses of 70 Gy in 35 daily fractions of radiotherapy delivered via IMRT or 3D-CRT. Primary end points included PEG tube dependence 1 year after radiotherapy start, weight loss during treatment, and change in Eastern Cooperative Oncology Group performance status. Secondary end points included overall and disease-free survival, disease recurrence, and toxic effect profiles. The IMRT group (n = 103) had a significantly lower rate of PEG tube dependence 1 year after treatment initiation than the 3D-CRT group (n = 56) for all patients (P = .02) and for those with advanced T stage (P = .01) and a shorter time to PEG tube removal (P < .001). Acute grade 3 or greater toxic effects to skin and mucous membranes occurred less frequently in the IMRT group (P = .02 and P < .001, respectively). The 2 groups did not differ significantly in weight loss, treatment failure (hazard ratio, 0.82 [95% CI, 0.47-1.41]), overall survival (P = .45), or disease-free survival (P = .26). The use of IMRT significantly improves PEG tube and toxicity-related outcomes compared with 3D-CRT in the treatment of oropharyngeal primary cancers. Given the association between mucosal toxic effects, PEG tube dependence, and dysphagia, these findings may be an indication of improved swallowing outcomes with IMRT.