Colon cancer is found during a colonoscopy, when a scope enables a physician to view the colon’s interior. Just how small can a colon cancer be when visualized?
“Colon cancers are thought to arise from a single mutation in a cell, which then gradually proliferates, reproduces and grows,” says Santosh Sanagapalli, MD, a consultant gastroenterologist, endoscopist and specialist in esophageal disorders.
“Therefore, there is no limit to how small a colon cancer may be,” – in the absolute sense.
But what about when it’s seen during a colonoscopy?
Dr. Sanagapalli continues, “However, colon cancers rarely arise from completely normal tissue, and the vast majority of cancers arise within an abnormal area of precancerous tissue in the colon (usually, a colonic polyp).
“Therefore, even very tiny, microscopic tumors are usually identified and removed at colonoscopy because we are able to see the larger precancerous polyp from which the cancer has arisen.”
In other words, the precancerous polyp is spotted during the scoping, removed and analyzed under a microscope, where a microscopic cluster of malignant cells is then identified by a pathologist.
Keep in mind that tiny malignant masses that are not visible to the naked eye or during a colonoscopy are usually NOT found in a removed precancerous polyp.
If a polyp was found, do not panic. In fact, the growth will, more likely than not, be benign (called hyperplastic) – and these are considered to have very little, if any at all, malignant potential.
“With the advances in imaging technology, modern colonoscopes allow gastroenterologists to see polyps 1 mm or smaller in size,” says Dr. Sanagapalli.
“It would be exceedingly rare for a cancer to arise within a polyp that is 1 mm or less in size.
“In fact, cancer is rarely encountered in polyps up to even 10 mm in size.”
Men and women of average risk for colon cancer (e.g., no family history) should start having screening colonoscopies at the age of 45 according to the U.S. Preventive Services Task Force.
Dr. Sanagapalli is a gastroenterologist and director of the Esophageal Disorders Center at St Vincent’s Hospital, Darlinghurst. He performs diagnostic and therapeutic endoscopic procedures, and enjoys providing comprehensive and holistic care to patients with a wide variety of disorders affecting the gastrointestinal tract.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.