Dosimetric analysis of lymphopenia during chemoradiotherapy for esophageal cancer

Esophageal carcinoma accounts for nearly 17,000 annual cancer cases in the United States (450 K worldwide) and portends a very poor prognosis with a 5-year overall survival (OS) rate less than 20% (1). Standard of care treatment for esophageal cancer (EC) treatment in order to optimize chances of a pathological complete response consist of neoadjuvant chemoradiation (CRT) followed by surgical resection (2) or, when unresectable, definitive CRT (3). Treatment related lymphopenia has been associated with a poor prognosis in several solid tumor disease sites including lung, head and neck, pancreatic, breast, and EC (4-8), and has been associated with decreased rates of overall survival (OS), disease free survival (DFS), and distant metastasis free survival (DMFS). It is hypothesized that the relationship between lymphopenia and prognosis may be in large part driven by an associated decrement in cytotoxic T cell activity against neoplastic cells (9)