DOES TUMOR LOCATION AFFECT RESPONSE TO NEOADJUVANT THERAPY IN GASTRIC CANCER?
Shankar Logarajah*1, Zarah Rahman1, Anthony Basta1, Maitham A. Moslim1, Michael Jureller1, Houssam Osman1,2, D. Rohan Jeyarajah1,2
1Methodist Richardson Medical Center, Richardson, TX; 2Texas Christian University, Fort Worth, TX
Introduction
Clinical trials involving esophgeal, GEJ, and gastric adenocarcinoma often group these tumors together. The NCCN guidelines currently recommend therapies interchangeably between tumors in these locations. No prior study has evaluated the degree of response to therapy between tumors in these locations after neoadjuvant therapy.
Methods and Procedures
A retrospective chart review of patients who were diagnosed with gastric cancer at a single institution was performed. Tumors of the GEJ and fundus were classified as proximal tumors whereas tumors of the body and antrum were classified as distal tumors. Patients were stratified into proximal tumor and distal tumor groups, their modified Ryan score on pathology after surgery was obtained, and univariate analysis was performed.
Results
90 patients who were treated for gastric cancer were identified between 2012-2020. Of these patients 85 (94%) underwent oncologic resection. 56 of the 85 (65.8%) patients who underwent surgery received neoadjuvant therapy (NAT). Amongst patients who received NAT, the majority received either FLOT (39%) or ECF/ECX (46.4%). 29 (53.7%) of patients who received NAT had proximal tumors and 25 (46.3%) had distal tumors. Amongst proximal tumors, 10 (34.5%) had a complete pathologic response, 10 (34.5%) had near complete response, and 9 (31%) had a partial response. Amongst distal tumors, 9 (36%) had a complete pathologic response, 11 (44%) had a near complete response, and 5 (20%) had a partial response. Between proximal and distal tumors, there was not a significant difference in Ryan score after NAT ( p = 0.621).
Conclusion
This is the first study to our knowledge examining pathologic response to NAT in gastric cancer based on tumor location. There did not appear to be a significant difference in the degree of pathologic response between tumors of the distal stomach versus proximal stomach. Although arising from presumably different etiologies, adenocarcinomas in these different locations of the stomach appear to respond similarly to NAT.
Pathologic response to neoadjuvant therapy categorized by the Modified Ryan Score for patients with proximal gastric tumors versus distal gastric tumors.
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