Association of clinical complete response (cCR) after preoperative chemoradiation and pathological complete response (pathCR) in patients with gastroesophageal cancer (GEC) and indispensability of trimodality therapy (TMT)

4086 Background: TMT strategy has the highest level-1 evidence for treating localized GEC. High rates of cCR (defined as post-chemoradiation negative endoscopic biopsy and physiologic uptake on PET) are common and have questioned the benefit from surgery in patients with cCR after chemoradiation. We hypothesized that cCR would be associated with a high rate of pathCR than < cCR. Methods: The data were analyzed retrospectively in 563 patients who had esophagectomy for GEC in between 2002 and 2010 at UTMDACC. Among them, 284 had TMT and post-chemoradiation endoscopic biopsies and PET (before surgery). Multiple statistical methods were used. Results: Of these 284 TMT patients, 218 (77%) patients achieved a cCR. However, only 67 (31%) of 218 had a pathCR. The sensitivity of cCR for pathCR was 97.1 % (67/69) but the specificity was low, 29.8 % (64/215). Intriguingly, 66 patients who had < cCR, only 2 patients (3%) had a pathCR. The difference in the rate of pathCR between the cCR and < cCR groups was significant (P < 0.001). Conclusions: Our data show that cCR is frequent after chemoradiation but the pathCR rate is not high and it is associated with specificity that is too low for clinical implementation. Therefore, all TMT-eligible patients, irrespective of the achievement of cCR or < cCR must be encouraged to undergo surgery. Therapies that overcome chemoradiation resistance and could increase the pathCR rate are needed for esophageal preservation in select GEC patients. Supported by UTMDACC and generous donors. [Table: see text]