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Pathological Response Does Mean Something: An Analysis of Gastric Adenocarcinoma
Muhammad U. Butt*, D Rohan Jeyarajah, Alyssa Chapates, Houssam Osman
Surgery, Methodist Dallas Medical Center, Dallas, TX
Introduction:
Medical Research Council Adjuvant Gastric Infusional Chemotherapy (MAGIC) trial demonstrated a survival benefit of neoadjuvant chemotherapy in patients with resectable gastric cancer. The efficacy of chemotherapy is evaluated based on degree of response in the surgical specimen. This response is classified as pathological response (PR). Radiological response (RR) is based on preoperative CT and PET scan following neoadjuvant chemotherapy. Our aim was to determine whether there is a correlation between pathological and radiological response in resected gastric cancer patients undergoing neoadjuvant chemotherapy. We also looked whether there was any survival advantage.
Methods:
Twenty-seven patients with gastric adenocarcinoma, including GEJ per NCCN guidelines who underwent neoadjuvant chemotherapy between January 2011 and December 2013 were identified retrospectively from our cancer registry. Patient demographics, stage of disease, PR based on final pathology report, and survival data was analysed.
Results:
All 27 patients underwent the MAGIC protocol neoadjuvant chemotherapy followed by resection. High resolution CT and PET scan were used post chemotherapy to grade the RR. The RR was graded into Grade 0 (Improved), Grade 1 (No improvement) and Grade 2 (Progression). RR could be evaluated in 24 patients. The PR was based on final pathology report. The PR was graded into Group A (Complete/Marked response in 3 patients) and Group B (Moderate/No response in 24 patients). There was no statistical difference in patient demographics between the groups. Intergroup analysis did not show any correlation between PR and RR. Using PR as the constant variable intergroup analysis did show a statistically significant survival advantage; Group A vs. B (p<0.03).
Conclusion:
This study demonstrates a survival advantage in patients that had a complete to marked PR to chemotherapy. The PR of gastric cancer to neoadjuvant chemotherapy did not correlate to the RR. This study lays the foundation of larger trials to identify patients who could potentially be converted to complete PR and in doing so improve survival.
Pathological response (PR) correlation to Radiological Response (RR)
| | Group A - PR | Group B - PR | p-Value | | Improved RR | 2 (66.7%) | 12 (52.1%) | 1 | | No RR | 1 (33.3%) | 9 (42.9%) | 1 |
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