Dose-escalated image-guided radiation and weekly cisplatin for inoperable squamous cell carcinoma of thoracic esophagus.

Abstract

e15120 Background: This study evaluates feasibility, toxicity and early outcomes of image guided volumetric modulated arc therapy (IG-RA) and weekly cisplatin for locally advanced inoperable squamous cell carcinoma (LAI-SCC) of thoracic esophagus. Methods: 41 patients diagnosed with LAI-SCC were included. Patients with performance status (ECOG) more than 1, involvement of cervical esophagus or gastroesophageal junction, distant metastasis were excluded from study. Radiotherapy was planned in two phases to a dose of 5940cGy. Phase I CTV was generated by expanding the GTV-primary craniocaudally(CC) by 4cm and laterally to include electively, the corresponding level mediastinal nodes. In the Phase II, GTV was expanded by 2cm CC and 1cm radially. ITV was generated by expanding the CTV by 0.5cm which was then expanded by 0.5cm to yield PTV. Chemotherapy consisted of 4-6 cycles of weekly cisplatin 40mg/m2. Results: The median age of patients was 53 yrs (43-72). The median length of involvement was 6cm with 80% of lesions in upper and middle third. 37/41(90%) patients completed planned chemotherapy with atleast 4 cycles of cisplatin and 40/41 patients completed full dose of radiotherapy. 10% of patients required tube feeding and 5% required hospital admission for supportive care. Endoscopy at 8 weeks post treatment was performed in 38/41 patients of whom 53% had CR, 42% had PR and 5% had stable disease locally. With a median follow up of 19 (6-32) months, 41% of total patients (17/41) are alive at last follow-up of which 32% (13/41) are disease free with no dysphagia, the 1 and 2 year overall survival are 70% and 40% respectively and median survival of 14 months. 16% alive patients have post radiotherapy stricture. The analysis of CBCT and KV image data sets showed a significant intra-fraction and inter-fraction motion of the target. The ITV and PTV margins of 0.5cm each were found to be adequate with current imaging protocol. Conclusions: IG-RA to a dose of 60Gy with concurrent weekly cisplatin is a feasible treatment option for LAI-SCC of thoracic esophagus with low acute and late toxicity and with promising early clinical outcomes. The ITV and PTV margins of 0.5cm were found to be adequate only with image guidance.