Hi thanks for asking question. First of all do not directly jump over cancer. Here are few possibility. 1. It could be bacterial entetocoilitis.for which stool examination done that might show pus cell and bacteria. Antibiotic like ofloxacine and ornidazole combination might needed. 2.Second it might be simple viral gastroenteritis or ulcerative condition.complete blood examination done that might reveal lymphocytosis if viral infection.treat it symptomatically and omeprazole. 3.Third you might have food allergy like condition.You might have gluten hypersensitivity like gluten containing diet like wheat, rye etc.that should be avoided. 4.Anal fissure if associated lead blood in stool.treated symptomatically with stool softener. 5.If still cause not clear then ultrasound examination and colonoscopy like investigation needed.that might reveal inflammatory bowel disease. Wish you good health. Dr.parth