Downstaging capacity of neoadjuvant chemotherapy in distal versus proximal gastric carcinoma: Preliminary data from a regional tumor registry.

Abstract

120 Background: Following the results of 3 randomized controlled trials, neoadjuvant chemotherapy has become standard of care for locally advanced gastric cancer in Europe. All of these trials included patients with cancers located in the gastric corpus, antrum, and pylorus (distal gastric cancers, DGC) as well as cancers of the esophagogastric junction and fundus (proximal gastric cancers, PGC). However, data suggest that DGC and PGC may be two distinct tumor entities. The aim of our study was to investigate if the capacity of neoadjuvant chemotherapy to downstage gastric cancers is different for DGC and PGC. Methods: We used data from the clinical regional tumor registry of Magdeburg which covers the northern section of the federal district of Saxony-Anhalt, Germany, to compare pretherapeutic (clinical) and postoperative (histopathological) UICC tumor stages in patients with DGC and PGC treated with neoadjuvant chemotherapy followed by surgery. Results: Of 2,460 gastric cancer patients entered into the registry between January 1993 and September 2010, 189 (7.7%) received neoadjuvant chemotherapy. Of these, 149 underwent surgery with curative intent. Pretherapeutic and postoperative UICC stages were not available for 34 of these patients. A further 42 patients had UICC stage IV documented at laparotomy; since this was likely due to peritoneal carcinomatosis which may have gone unnoticed at the start of neoadjuvant chemotherapy and thus does not reliably indicate upstaging, these patients were excluded from analysis. Of the 73 evaluable patients, 33 (45.2%) had DGC and 40 (54.8%) had PGC. UICC tumor stage decreased during therapy in 55.1% and 75.0%, remained unchanged in 16.3% and 20.8%, and increased in 28.6% and 4.2% of DGC and PGC patients, respectively (p=0.039, Fisher’s exact test). Conclusions: Despite the limited statistical power, these preliminary data suggest that DGC and PGC may differ in their response to neoadjuvant chemotherapy. With more widespread use of neoadjuvant chemotherapy in gastric cancer in recent years, we expect a steep increase in evaluable patients in the tumor registry which will allow for future multivariate analyses regarding this issue.