A prospective phase I study of hypo-fractionated neoadjuvant radiotherapy for locally advanced gastric cancer.

ABSTRACT

BACKGROUND: Previous studies have reported that neoadjuvant chemoradiotherapy can downstage the advanced gastric cancer. However, no studies are available on the application of hypo-radiotherapy to neoadjuvant radiotherapy. This study sought to assess the maximum tolerated dose (MTD) and dose-limited toxicity (DLT) of hypo-fractionated chemoradiotherapy for local advanced gastric cancer. METHOD: Patients with cT3-4 and/or lymph node-positive locally advanced gastric cancer or Siewert II/III esophagogastric junction adenocarcinoma were enrolled. Preoperative chemoradiation was followed by 3 cycles of oxaliplatin + S-1 neoadjuvant chemotherapy with an interval duration of 3-4 weeks. D2 resection was performed 2-4 weeks after neoadjuvant therapy. Three cycles of adjuvant chemotherapy were planned after surgery. Intensity-modulated radiotherapy (IMRT) was used. The radiotherapy dose level was defined using three levels, namely, 40.0 Gy/2.5 Gy, 41.6 Gy/2.6 Gy, 43.2 Gy/2.7 Gy delivered concurrently with S-1 at 80 mg/m2. RESULTS: From May 2016 to Dec 2016, nine patients with a median age of 63 years were enrolled in this study. The most common grade I-III adverse events were leukopenia (88.9%), nausea (88.9%), vomiting (77.8%) and weight loss (66.7%). Grade III adverse events consisted of vomiting and weight loss. CONCLUSION: The MTD of hypo-fractionated radiotherapy for locally advanced gastric cancer was 40.0 Gy/2.5 Gy, and the DLTs were vomiting and weight loss. TRIAL REGISTRATION Clinicaltrials.gov ID NCT03427684 (Retrospectively registered on February 9, 2018).