Anal cancer is rare and often confused with colon or rectal cancers. While these cancers are similar in many ways, their treatments differ. Anal cancer occurs in the last two inches of your large intestine, where stool leaves your body. Symptoms include bleeding, pain, lumps, itching, and discharge. Patients who are HIV positive, even when treated, and transplant patients have a higher risk of anal cancer. You also are at a higher risk if you have anal sex. If you believe you are at high risk for anal cancer, you should be screened with annual anal Pap smears. If this test is abnormal, you will be tested further using high-definition anal microscopy, also called high-resolution anoscopy (HRA). Many precancerous changes can be safely treated in clinic using local anesthesia. Should a cancer be detected, early diagnosis leads to the greatest chance for treatment success.