Tomotherapy Versus 3D Conformal Radiation Therapy in Patients With Head And Neck Cancer Treated With Definitive (Chemo) Radiation Therapy

Abstract

Since the introduction of Tomotherapy in our center, it has not been possible to treat all head and neck cancer (HNC) patients on it due to logistic reasons. It was a unique situation where HNC patients were treated simultaneously by the same specialists using two different radiation therapy techniques in the same institute. The objective of this study is to evaluate the efficacy and toxicity of two techniques, i.e. Tomotherapy and 3D conformal radiation therapy in HNC patients treated with definitive (chemo)radiation therapy. Between March 2009 to February 2013, 165 consecutive patients with a biopsy proven squamous cell carcinoma of head and neck region treated with definitive radiation therapy 65 Gy in 30 fractions ± weekly cisplatin/cetuximab chemo(bio)therapy were included. The data was collected retrospectively, log-rank test was used for survival analysis; chi-square and Fisher’s exact test were used for group analysis. Ninety-seven patients received 3D conformal radiation therapy (3D CRT group) and 68 patients were treated with Tomotherapy (Tomo group). Median age was 63 years (range: 37-89) in 3DCRT and 58 years (range: 19-77) in the Tomo group. In both groups, oropharynx was the most common primary subsite (54% in 3D CRT and 63% in Tomo). Majority of the patients in both groups were of stage (TNM 7th edition) IVa (54% in 3D CRT and 66% in Tomo) followed by stage IVb (10% in each group). Of the patients in 3D CRT, 56.7% received concurrent chemotherapy (95% cisplatin, 5% cetuximab) while 86.8% of Tomo group received chemotherapy (92% cisplatin, 8% cetuximab). In 3D CRT, 67.3% of the patients completed all 6 cycles of chemotherapy compared to that 74.6% in Tomo group. Response was achieved in 93.8% cases in 3D CRT and 97.1% cases in Tomo group. In 3D CRT, 17 patients recurred locally and 8 developed distant metastases as compared to 14 and 10 respectively in Tomo group. With a median follow up of 42 months (range: 1-83), 1-year and 5-year disease-free survival were 80% and 63.7% in 3D CRT vs 88.1% and 77.1% in Tomo group. One-year overall survival and 5-year survival were 85.5% and 54.2% in 3D CRT group vs 85.3% and 62.1% in Tomo group. The incidence of acute toxicities was higher in Tomo group given the higher percentage of patients received concurrent chemotherapy. However, there was a trend of lower incidence of late toxicities in the Tomo group: bone necrosis (7 patients in 3D CRT vs 3 in Tomo, P=.52), complete xerostomia (18 vs 8, P=.24), and laryngeal cartilage necrosis (5 vs 1, P=.40). A significant difference was observed in late swallowing dysfunction requiring intervention (27 in 3D CRT vs 5 in Tomo, P=.02). There was no statistical difference in DFS and OS between two groups; however, we observed a trend of lower incidence of late toxicities in patients treated with Tomotherapy, with a significant difference in late swallowing dysfunction.