Effect of neoadjuvant dose-painted IMRT to 56 Gy for locally advanced esophageal cancer on outcomes.

Abstract

144 Background: Standard of care chemoradiation doses of 50.4 Gy for locally advanced (T3, T4, and/or node positive) esophageal cancer is associated with a pathologic complete response (pCR) rate of 40% at our institution. We evaluated whether pCR would be increased with 4D CT planning scans, intensity-modulated radiation therapy (IMRT) delivery with motion management, and dose painting to 56 Gy in 28 fractions. Methods: This retrospective review of 9 patients who have undergone esophagogastrectomy (7 adenocarcinoma, 2 squamous cell) evaluates our initial experience with neoadjuvant dose painted IMRT to 56 Gy. Pre-treatment workup included PET scan, chest and abdomen CT scans, endoscopic ultrasound (EUS), and EUS-guided fiducial marker placement. Fiducial markers were placed superior and inferior to the gross endoscopic tumor volume to facilitate analysis of tumor motion with 4D CT simulation. Internal target volumes (ITVs) of gross disease were generated to account for motion. Once the GITV was generated, a clinical target volume (CTV) encompassing a 3-4 cm superior margin and 3-4 cm distal margin was contoured. Two planning target volumes (PTVs) were created for dose painting: PTV 50.4 and PTV 56 Gy in 28 fractions. IMRT was utilized for all patients with either a weight belt or with compensators. Concurrent cisplatin and continuous infusion 5-FU were delivered with radiotherapy and patients were restaged 3-6 weeks after completion for response evaluation. Results: Treatment was well tolerated without any grade 3 acute morbidity. Surgical complications were not increased in this group overall. However, there was 1 patient with a chyle leak and radiation pneumonitis, but her case was complicated by having a remote history of radiotherapy. Six of the 9 treated patients were found to have a pCR (4 adenocarcinoma, 2 squamous cell). Two had a near CR with < 5 mm of residual disease. One additional patient with an initial bulky T4N1 tumor had 9 mm of viable tumor. Conclusions: With motion management, dose painted IMRT to 56 Gy is feasible and may be associated with improved rates of pathologic complete or near complete response. No significant financial relationships to disclose.