Plasma DNA as a molecular marker for completeness of resection and recurrent disease in patients with esophageal cancer

objective: To identify a marker for completeness of re section and recurrent disease in patients with esophageal cancer. Design: Case series. Setting: Department of Surgery of the University of Southern California. Patients: Forty-four healthy subjects and 45 patients with esophageal cancer prior to esophagectomy. Six patients were unresectable and 39 had a complete resection. Main Outcome Measures: Plasma DNA levels were measured using polymerase chain reaction. Twenty resected patients had follow-up plasma DNA levels measured. Results: Preoperatively, plasma DNA levels exceeded the normal level in 38 (84%) of 45 patients. Preoperatively, 12 patients received neoadjuvant therapy and 11 had plasma DNA levels higher than normal. All 6 unresectable patients had DNA levels higher than normal. At initial follow-up, the plasma DNA levels remained higher than normal in 2 (10%) of 20 patients, and systemic disease was subsequently detected in each. Plasma DNA levels dropped lower than or remained normal in 18 (90%) of 20. In 14 of 18 patients, there was no evidence of recurrent disease at a median of 12 months (range, 3-20 months); in 4 patients, the plasma DNA level rose higher than normal on follow-up and all developed subsequent systemic disease on computed tomographic or positron emission tomographic scan. Six of the 20 patients developed systemic disease during the follow-up (2 had persistently elevated plasma DNA levels, and 4 developed elevated plasma DNA levels at subsequent follow-ups). In 4 of these 6 patients, elevated plasma DNA levels were detected prior to imaging evidence of disease. Conclusions: Plasma DNA levels are significantly elevated in patients with esophageal cancer and following complete resection should return to normal. Persistently elevated plasma DNA levels after resection or levels that rise on follow-up indicate residual or recurrent disease.