Digital Rectal Exam Poor Predictor of Rectal Cancer
Posted by Kate Murphy on September 29th, 2008
Tags: DRE, rectal cancer, screening
When physicians exam the rectum with a gloved finger, they are unlikely to find a real tumor and more likely to refer patients unnecessarily for further tests. Digital rectal exams are a poor way to accurately identify rectal cancer according to a recently published study from the United Kingdom.
Doctors reviewed all referrals made to the the urgent colorectal cancer system at University Hospital of North Staffordshire because of a palpable rectal tumor between May and December of 2006. Of 1,069 referrals to the system, 108 were for rectal tumors that general practitioners reported they felt during a digital rectal examination.
However after further testing, only 32 or those 108 exams actually was a rectal tumor.
And 10 tumors, potentially within reach of the examination, were missed by referring general practitioners.
Considering those referrals that actually were not tumors and the missed tumors, accuracy for digital rectal exam in finding very low rectal cancer was 29 percent.
The research team, led by C. W. Ang concluded,
Digital rectal examination in primary care for palpable rectal tumour has a sensitivity of 0.762, specificity of 0.917, positive predictive value of 0.296 and negative predictive value of 0.988. It is an inaccurate procedure and a poor predictor for palpable rectal tumour.
In the Guidelines for Screening and Surveillance for the Early Detection of Colorectal Cancer and Adenomatous Polyps published in the US in March, 2008, the panel warned,
Screening for colorectal cancer with guaiac-based FOBT in the office following digital rectal exam or as part of a pelvic examination is not recommended and should not be done.
SOURCE: Ang et al., Colorectal Disease, Volume 10, Number 8, October 2008.
Deborah Kanter
September 30, 2008 at 8:31am
“Accurate digital rectal examination (DRE) enables the early diagnosis of palpable rectal tumour.”
The first sentence of the abstract is key here. Perhaps the digital rectal exam needs to be reevaluated as part of the traditional annual physical.
What might replace it? Will increased blood tests be a part of an exam?
Let’s hope that when oncologists perform the often dreaded “finger exam,” it is a helpful and accurate predictor; especially in longer term survivors.
Ruthie Pfueller
October 1, 2008 at 1:08pm
My cancer was discovered “accidently” when i went to my docotr for an aggreviated tailbone. He inserted his finger to adjust the joint to recieve a cortizone shot and I nearly came off the table screaming from the pain. AT this point he questioned me anout my bowl habitis ande made the decision to do a scope.
I went in for scope on Wednesday, had surgery on Friday and started my chemo and radation a few weeks later. BTW, I am 5 years post with clean bill of health, from my stage 2 colon rectal cancer, and if not for that accidental discovery, I may have died from it because I DID NOT KNOW the syptoms of colon rectal cancer.
I don’t remeber ever seeing a commercial listing the symptoms of colon rectal cancer. All I can remember knowing before my diagnosis is that you should eat lots of fiber. So awareness IS crucial.
Kate Murphy
October 1, 2008 at 1:38pm
I think the point of the research is that digital rectal exam is just not a good test for detecting rectal cancer and is rarely an accurate predictor of whether someone has rectal or colon cancer.
As to what will replace it — it has already been replaced by the recommended screening tests for colorectal cancer: FOBT, DNA stool test, flexible sigmoidoscopy, barium enema, CT colonography, or colonoscopy.
People without symptoms of colorectal cancer should discuss the sensitivity and risks of each of those tests with their doctors and how often to do them. DRE should not be considered a screening test.
Patients with any symptoms of colorectal cancer should have them evaluated by colonoscopy, no matter their age.
Colorectal cancer can be prevented with screening.