IS PROXIMAL GASTRIC CANCER A DIFFERENT ENTITY FROM DISTAL GASTRIC CANCER? ANATOMICAL SITE DISTRIBUTION OF SIGNET RING CELL CARCINOMA AND ITS ASSOCIATION WITH HELICOBACTER PYLORI INFECTION

Background: Despite many known variables affecting the outcome, little is known about the impact of histology on the location of tumour and outcomes. The objective of our study was to describe pattern of gastric cancer at single centre and association with H. Pylori and Signet ring cell variant with site of tumour in stomach. Methods: This was a cross sectional study conducted at the Department of Surgery of Aga Khan University Hospital, Karachi, Pakistan. A total of 105 patients who underwent surgery for gastric adenocarcinoma were classified to have a proximal, distal or whole stomach cancer. An association was determined between the tumour histology and helicobacter pylori infection with the location of tumour in the stomach. Results: Proximal gastric cancer was present in 27 (25.7%) patients and distal gastric cancer was present in 69 (65.7%) patients. There were 9 (8.6%) patients in whom tumour involved the whole stomach. Fifty-two patients (49.5%) had signet ring cell variant of gastric carcinoma and these patients were more like to have higher grade and advanced stage. Further analysis showed that that odds of proximal gastric tumour to have signet ring cell histopathology was 3.22 as compared to distal gastric tumour (p=0.017). Helicobacter Pylori infection status did not have any significant association with either grade of tumour or stage at the time of presentation. Conclusion: Despite limitations our data suggests that proximal gastric cancer may be biologically different from distal gastric cancers in terms of frequency of signet ring cell histology.