Three-dimensional conformal radiation therapy for squamous cell carcinoma of the esophagus: A prospective phase I/II study

Purpose: A prospective phase I-II study was conducted to determine the tolerance and local control rate of three-dimensional conformal radiotherapy (3-DCRT) for esophageal squamous cell carcinoma (SCC). Methods and materials: Thirty patients underwent 3-DCRT for thoracic esophageal SCC. PTV1 composed of a 1.2-1.5 cm margin lateral around GTV and 3.0 cm margin superior/inferior of GTV. PTV2 encompassed GTV with a margin of 0.5-0.7 cm. The dose for PTV1 was 50 Gy in 2 Gy daily fractions; PTV2 received a boost of 16 Gy in 2 Gy daily fractions to a total dose of 66 Gy. Results: Median follow-up time was 18 months. The most common acute toxicity was esophagitis in 63% of patients with RTOG grades 1-2, and in 3% with grade 3. RTOG grades 1-2 radiation pneumonitis developed in 27% of patients. One patient developed pulmonary fibrosis RTOG grade 2 and another patient experienced grade 3 pulmonary fibrosis. Two patients developed mild esophageal stricture requiring dilatation. Two-year overall survival, local disease progression-free rate, and distant metastasis-free rate were 69%, 36% and 56%, respectively. Conclusions: Although 3-DCRT to 66 Gy for esophageal SCC was well tolerated, the local control was disappointing. The result supports the use of chemoradiation as the standard care for esophageal SCC.