Malignant Sources of Lower Gastrointestinal Hemorrhage Robert D. Madoff, MD University of Minnesota

17-20% of individuals in the community have rectal bleeding each year

“It’s my hemorrhoids, doc” = “Is it cancer, doc?”

LGI bleeding sources

causes of LGI bleeding diverticula polyps cancer angiodysplasia inflammatory bowel disease hemorrhoids ischemia radiation Meckel’s diverticulum rectal ulcer anal varices

LGI bleeding the classical view characteristicsource red blood, toilet paper or toilet water perineal or anal red blood, coating stoolanal or rectal red or darker blood, streaking or mixed with stool left colon maroon stoolright colon or small bowel

diagnostic value of dark red rectal bleeding sensitivity (%) specificity (%) (+) PPV (%) Ellis Metcalf Chave

disadvantages of colonic investigation anxiety risks –bleeding –perforation –death cost inconvenience consumption of limited resources

Bayes theorem The likelihood of a true positive examination depends upon the “prior probability” of the condition in question in the population being studied.

predictive value of rectal bleeding for cancer community1:700 primary care clinic1:30 surgical clinic 1:17

Sutton’s law “go where the money is”

colorectal cancer presenting signs and symptoms signs rectal mass abdominal mass hepatomegaly abdominal distension microcytic anemia CEA cachexia symptoms hematochezia melena altered bowel habits stool caliber abdominal pain nausea/vomiting obstipation tenesmus anorexia fatigue, weakness

family history life-time risk of colorectal cancer no family history of CRC……………………….6% one 3 0 relative with CRC…...……...…….....…..8% one 2 0 relative with CRC………………………..9% one 1 0 relative with CRC over 50y…………..12% one 1 0 relative with CRC under 50y…………25% two 1 0 relatives with CRC under 50y………..35% Giardello 2000

Bayes again… investigation of a low-risk population will result in a high rate of false positive examinations

sudden, large-volume, fresh red rectal bleeding low risk of large bowel cancer

Incidence Increases with Age (93% > 50 yrs)

peak incidence of rectal bleeding is age 20-40; fewer than 1% of large bowel cancers occur in this age group

“Is it cancer, Doc?” 75% of cancer patients who present with rectal bleeding have an associated change in bowel habits

rectal bleeding plusrelative risk of colon cancer change in bowel habits*5x anal symptoms0.2x Figten 1995 Ellis 1999 *especially loose or frequent stools

cancer risk by symptom profile agerectal bleeding + change in bowel habits - abdominal pain or anal symptoms <391:2681:731: :831:321: :261:131: :101:61: :81:61:3 > 801:51:41:2 Thompson

“It’s my hemorrhoids, doc” = “Is it cancer, doc?”

malignant sources of lower GI hemorrhage most LGI bleeding is from a benign source use some judgment: let risk profile be your guide

“increased risk” population age family history history of polyps history of cancer underlying IBD symptom complex

“If there is any doubt, there should be no doubt” Richard C. Varco, MD