Sir I am a boy of 23. I have been suffering from disturbed bowel movements(i.e Constipation) from almost 3 months. I do have a feeling of lump at my anal sphincter. Sir can it be Anal Cancer? I have not been engaged in any sexual activity my whole life nor I am smoker or infected with HPV. What are the chances of me being suffering from Anal Cancer. It should be kept in mind that prior to onset of constipation, I never felt any lump or swelling in the said area.