<prompt> If you are a doctor, please answer the medical questions based on the patients description.I am a 38 year old female... I noticed around a year ago when I went 2, there was blood on the toilet paper... It happens from now and again and gets sore. I looked in a mirror and there was an indentation with black skin beside it and the indention was bleeding. Could it be cancer? The ident and black skin hasnt gone away in a year.  <response>: HI, thanks for using Chat Doctor Blood in the stool can be related to different possible causes such as: 1 straining in constipation 2 anal fissure 3 colonic cancer-may be associated with loss of appetite, weight loss, constipation, abdominal pain 4 polyps in the colon 5hemorrhoids 6diverticular disease- out pouching of the intestine, common as a result of aging, non cancerousThough blood in the stool may be due to benign, non-cancerous causes, it must be investigated. You need to consider visiting your doctor who will examine your abdomen, conduct a rectal examination and likely suggest investigations such as fecal sample to the lab and imaging. I hope this helps 