Comparison of esophagus dose in breast cancer patients undergoing supraclavicular irradiation with and without esophagus countering.

Abstract

Esophagus toxicity and the risk of esophageal cancer are linked to radiation dose to the esophagus in breast cancer patients undergoing supraclavicular irradiation. The aim of this study was to evaluate the impact of esophagus contouring on the dose received in the esophagus in breast cancer patients undergoing supraclavicular irradiation. This study included 30 treatment plans for breast cancer patients who received 50 Gy/25 fractions (2 Gy/fraction/day) using 3D-conformal radiation therapy (3D-CRT) to the whole breast or chest wall and supraclavicular. Our study included two groups: the non-sparing group was the treatment plan in which the esophagus was not delineated and the esophagus sparing group was generated, in which the plans were modified to spare the esophagus. The maximum dose, mean dose, and percentage of esophagus volume received, 5, 10, 15, and 20 Gy, respectively (V5, V10, V15, and V20), were used to evaluate both groups. One-way analysis of variance was used. A P value <0.05 was considered statistically significant. The esophagus sparing group plans show a reduction in the esophageal mean dose Dmean (5.72 ± 5.15) Gy when compared to the non-sparing group (7.83 ± 3.31) Gy. Likewise, the maximum dose, V5, V10, V15, and V20 were reduced in the esophagus sparing group. All dosimetric parameters were significantly higher (P < 0.05) in patients with left breast cancer for both groups. Our results suggest that it is possible to reduce the dose to the esophagus by considering the esophagus during treatment planning while maintaining plan quality. This reduction could lead to the greatest predicted decrease in acute esophagitis and esophageal cancer.