Central  South  Dakota Medical News
The Clinical View
by P.E. Hoffsten, MD
15  AUG  2002

COLON CANCER

Of all the various cancers, the one that can be absolutely prevented through routine screening is cancer of the colon.  As short a time ago as 1962, cancer of the colon was thought to be a random event with no rhyme or reason as to why it occurred.  But over the years since then, some very astute physicians took notice of a disease called familial polyposis.  This disease is a strange one in which the family members have virtually hundreds of polyps grow in their colon.  Note that a polyp is rather like a grape that grows off the inside of the colon like a little hanging down piece of flesh.  In people who have familial polyposis, cancer of the colon would develop by the time they were 20-30 years old.  It had long been known that once this disease was diagnosed in a family, affected individuals needed to have their colons removed in their mid 20’s or sooner.

These very astute physicians reasoned that if cancer of the colon came so early in patients that had familial polyposis perhaps removing polyps from people that only have a few of them would prevent cancer of the colon in the general population.  Through a large number of studies, it was found that indeed for practical purposes virtually all cancers of the colon originate on something called an adenomatous polyp of the colon.   It was noted that in addition, that these polyps on the average tend to change from benign growth into malignant cancer growths on the average after seven years.

It thus didn’t take a great reach to reason that if polyps are removed before they become malignant, cancer of the colon can be absolutely prevented.  I don’t mean treated and cured or having surgery to remove a section of the colon.  I mean the cancer will never happen if the polyps are removed before they become cancerous.

Cancer of the colon is relatively rare before age 50 unless there is a strong family history of same.  Thus, it is recommended that at age 50, all individuals have a screening flexible sigmoidoscopic examination of the colon to see if polyps are present.  If polyps are found, they are removed and examination is repeated in three years.  If no polyps are found, the examination can be repeated in five years and if none are found then, the person is relatively safe from developing colon cancer in the future.

How important is this examination?  Every year approximately 1,300,000 new cancers are found in the United States.  Roughly half of the people who develop a cancer die from it.  For colon cancer, there are about 110,000 new cases per year equally distributed between men and women.  Roughly half of the people who develop this type of cancer will die from it.  It is the third leading cause of cancer death in our society.  Thus screening to prevent this cancer altogether is a very useful endeavor.

Please note the difference between screening colonoscopy and the annual checking the stool specimen for hidden blood.  By the time there is blood in the stool specimen, the cancer is already present.  The polyps that are in the colon rarely bleed on their own and if blood is present in the stool, it generally means that the colon cancer is already present and will have to be treated either with surgery or chemotherapy.  This is a very different strategy than having sigmoidoscopic examinations that detect the polyps before the cancer ever develops.  Rural Health Care, Inc. has as one of their missions the next several years, the early detection and prevention of cancer.  One of the targeted cancers that they are going to work on is cancer of the colon.  The local clinics in your community can provide a starting point to arrange for appropriate screening examinations to prevent cancer of the colon.