Testing, Testing

Today while going through Twitter I ran across a tweet written by a woman mourning a friend who died of colon cancer at age 39. Her post states the friend's father died "young" (she does not say how young) of colon cancer, and therefore the friend requested a colonoscopy. According to the post, the screening was denied; insurance wouldn't pay for it. The friend was not diagnosed until her cancer had metastasized. The tweet has attracted thousands of retweets and hundreds of comments, many of which give other examples of friends and family members dying early of colon and other cancers. The responders' chorus: "Why wouldn't insurance pay for this? Why! This could have been avoided!" as well as the mandatory curses thrown at the US health system and insurance companies.

Make no mistake, this is a tragedy. Unfortunately there isn't enough information given in the tweet to fully critique what happened. My first question, however, was: was this person offered a FIT test? FIT is an abbreviation for fecal immunochemical test and is a test to check for blood in the stool. More recently, a more sensitive test called Cologuard has become available (it checks for DNA markers in the stool which are compatible with colon cancer or certain types of polyps). It is more expensive than the FIT test and many insurances do not cover it; however, it is still a lot cheaper than a colonoscopy. Either of these tests could have helped diagnose the woman at an earlier stage. If these tests came back positive, it would definitely have influenced the decision to proceed with colonoscopy.

Second: the current standards for colonoscopy in the US are that you begin screening at age 45 or, if there is a family history of colon cancer in a near relative, when the patient's age is ten years younger than the relative's at time of diagnosis - whichever is sooner. "Screening" here refers to colonoscopy, although many people decline them, in which case they can choose to be screened annually with a FIT test or with Cologuard every three years. The US screening recommendations have evolved over the years to become more aggressive, as I will discuss further.

As always, the benefits of the UK health system are being talked up. For comparison I will present the NHS testing policy for colon cancer, as follows: FIT screening every other year, not annually, and screening is recommended between the ages of 60 and 74 (it can be extended beyond age 74 upon request by the patient). The NHS is considering extending screening back to age 50 but this has not yet taken place. Colonoscopy is not part of routine screening. 

When I began my training, screening for colon cancer consisted of sigmoidoscopies rather than full colonoscopies and screening began at age 50. The sigmoid colon is the last 40 cm of the colon, about 25 percent of the entire colon. Initially it was thought that the majority of colon cancers originated in the sigmoid colon, but we now know this is no longer true. Full colonoscopies became the norm after the well-publicized death of Jay Monahan in 1998. He was the husband of a journalist named Katie Couric, and had been screened with sigmoidoscopy but not full colonoscopy; Ms. Couric made it her cause to urge more aggressive screening techniques and this was changed. More recently, the age to begin colon cancer screening has been pushed back to age 45, as noted above. This is due to colon cancers trending at a younger age. 

"Why not sooner?" - in general, colon cancer is not a young person's illness. There are very specific exceptions to this, involving genetic syndromes such as familial adenomatous polyposis, but they are rare. These syndromes have been closely studied and in many cases early colectomy, such as by age 30 or 35, is recommended to prevent onset of colon cancer. Now, screening recommendations can always be changed as I have outlined above; they are not set in stone. But there is always a balance between risks and benefits of screening. Colonoscopy involves anesthesia as well as the risks of perforation of the colon and bleeding. (These complications are rare, but they can happen.) The less invasive forms of screening, FIT and Cologuard, can give false negative and false positive results. This means that someone could wind up getting an unnecessary colonoscopy due to a false positive result, or that a cancer can be missed. Going on a snipe hunt to check a questionable result leads to increased risk and expense. In a very low risk population (such as below age 45), the risks and expense will outweigh the benefits. For every cancer found in this age group there are a lot of useless procedures. It's all about statistics, and this is why doctors as well as insurance companies - and the US preventive services task force, come to that - are generally reluctant to recommend screening at a very early age. 

Symptoms of colon cancer at an early stage are very nonspecific. Constipation, bloating and abdominal pain can all be symptoms; unfortunately the majority of the time, they are not. Functional bowel symptoms are incredibly common, meaning that the patient has symptoms but no disease can be found even with radiologic testing or colonoscopy. It is simply not possible to work up everyone who presents with these symptoms. Of course, trying to point this out to someone who has lost a relative or close friend to cancer is a loser's game. What I try to do is listen, do a good exam, run a blood count to check for anemia and encourage the patient to follow up or email me if the symptoms continue or change. Screening has done a lot to extend lifespan by catching problems early, but it is not perfect. 

Labels: Cancer, Medicine