Results and Molecular Correlates from a Pilot Study of Neoadjuvant Induction FOLFIRINOX Followed by Chemoradiation and Surgery for Gastroesophageal Adenocarcinomas

Purpose: We performed a NCI-sponsored, prospective study of neoadjuvant FOLFIRINOX followed by chemoradiation with carboplatin/paclitaxel followed by surgery in patients with locally advanced gastric or gastroesophageal cancer. Patients and Methods: The primary objective was to determine completion rate of neoadjuvant FOLFIRINOX x 8 followed by chemoradiation. Secondary endpoints were toxicity and pathologic complete response (pCR) rate. Exploratory analysis was performed of circulating tumor DNA (ctDNA) to treatment response. Results: From October 2017 to June 2018, 25 patients were enrolled. All patients started FOLFIRINOX, 92% completed all eight planned cycles, and 88% completed chemoradiation. Twenty (80%) patients underwent surgical resection, and 7 had a pCR (35% in resected cohort, 28% intention to treat). Tumor-specific mutations were identified in 21(84%) patients, of whom 4 and 17 patients had undetectable and detectable ctDNA at baseline, respectively. Presence of detectable post-chemoradiation ctDNA (P = 0.004) and/or postoperative ctDNA (P = 0.045) were associated with disease recurrence. Conclusions: Here we show neoadjuvant FOLFIRINOX followed by chemoradiation for locally advanced gastroesophageal cancer is feasible and yields a high rate of pCR. ctDNA appears to be a promising predictor of postoperative recurrence.