CHARACTERISTICS AND SURVIVAL OF GASTRIC CANCER PATIENTS WITH PATHOLOGICAL COMPLETE RESPONSE
Alexander P. Stark*1, Naruhiko Ikoma1, Yi-Ju Chiang1, Jeannelyn Estrella2, Prajnan Das3, Bruce D. Minsky4, Mariela Blum4, Paul Mansfield1, Brian Badgwell1
1Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX; 2Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX; 3Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX; 4Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX
BACKGROUND: Pathological complete response of a primary tumor (ypT0) after preoperative therapy is an indicator of a treatment effect often associated with improved survival. However, whether other variables are associated with outcome in gastric cancer patients with ypT0 status is unknown.
METHODS: We reviewed a prospectively maintained institutional database of patients who underwent potentially curative resection of gastric or gastroesophageal adenocarcinoma after preoperative therapy and identified patients with ypT0 status. We used univariable and multivariable Cox regression models to identify clinicopathological predictors of overall survival (OS) in ypT0 as well as ypT0N0 patients.
RESULTS: We identified a total of 77 patients with ypT0 status. Thirty-six (47%) had gastroesophageal junction tumors. The majority of patients presented with clinical T3 disease (n=62 [81%]). In addition, 7 patients with clinical T4 disease achieved ypT0 status (9%). The clinical nodal status was positive in 45 patients (58%). Seventy-five patients (97%) underwent preoperative chemoradiation. Eight patients (10%) needed concomitant en bloc organ resection. After treatment, 67 patients (87%) had negative lymph nodes (ypT0N0). The median follow-up duration was 3.54 years. The median OS was 10 years, and the 5-year OS rate for the entire cohort was 61%. Univariable analysis identified age greater than 65 years at the time of diagnosis, histological grade, and ypN status as significant predictors of OS. Multivariable analysis confirmed age greater than 65 years (hazard ratio, 4.26; p<0.001) and ypN+ status (hazard ratio, 5.12; p<0.001) to be independently associated with OS. Clinical TNM stage was not associated with survival. In ypT0N0 patients, no single preoperative clinicopathological feature was predictive of survival.
CONCLUSION: For patients with gastric or gastroesophageal adenocarcinoma having ypT0 status after preoperative therapy, persistent nodal disease (ypN+ status) substantially influenced survival. The pretreatment clinical stage had no impact on OS for patients with ypT0 or ypT0N0 status after preoperative therapy.
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