RESUMEN
Of 1600 Saudi patients who underwent lower gastrointestinal tract endoscopy at the Riyadh Armed Forces Hospital, 40 [2.50%] had adenomatous polyps, 12 [0.75%] had colorectal cancer, 149 [9.31%] had Schistosoma mansoni, and 5 [0.31%] had schistosomal polyps but with no associated malignancy. Despite the high incidence of S. mansoni, there was no increase in the incidence of colorectal cancer in these patients. Of 1846 Saudi patients seen at the oncology department, 346 [18.74%] had gasterointestinal malignancy [307 in the upper gastrointestinal and 39 in the lower gastrointestinal tract]. This distroibution of neoplasms in the alimentary tract is almost the reverse of the seen in the West. There is a low incidence of adenomatous polyps and colorectal cancer in Saudi patients compared to the Western population. This might be due to genetic, dietary, and environmental factors. The present study also confirms previous studies from Egypt that S. mansoni infestation dose no play a role in or predispose to large lowel malignancy