Comparison of Locoregional versus Extended Locoregional Radiation Volumes for Patients with Nonmetastatic Gastro-esophageal Junction Carcinomas

Introduction: To delineate an optimal clinical target volume (CTV) for gastroesophageal junction (GEJ) cancers by comparing locore- gional versus extended locoregional radiation (RT) volumes. Materials: This retrospective analysis examined 222 patients (111 matched pairs treated with locoregional versus extended locore- gional RT) with nonmetastatic GEJ carcinomas treated with concur- rent chemoradiation ± surgery. The CTV for locoregional volumes was defined as gross tumor volume + elective coverage of first-ech- elon nodes and sometimes the celiac axis. The CTV for extended locoregional volumes was defined as gross tumor volume + elective coverage of celiac and splenic (±porta) nodes. Variables used for matching included sex, stage, performance status, histology, receipt of induction chemotherapy, type of concurrent chemotherapy, RT modality, receipt of surgery, type of surgery, and Siewert classifica- tion. Regression models stratified by matched pairs were fit to esti- mate effect of RT volume on clinical endpoints. Results: Adjusting p values for multiple testing, patients treated with extended locoregional versus locoregional RT had increased odds of grade 2+ acute chemoradiation-associated gastrointestinal toxicity (odds ratio: 2.92, adj. p = 0.0447). However, differing RT volumes were not significantly associated with postoperative complication rates, pathologic T-stage, frequency of positive perigastric/regional nodes on surgical specimen, distant-metastases progression-free survival, locore- gional progression-free survival, or overall survival (adj. p > 0.05). Of the patients who did (n = 124) and did not (n = 72) receive elective celiac RT, two (1.6%) and two patients (2.8%), respectively, relapsed in the celiac nodes. No patients failed in the splenic or porta nodes. Conclusions: Most GEJ cancers can be safely treated without elec- tive inclusion of splenic/porta nodes.