Is Colorectal Cancer Only For Over 50?

The prevailing belief about colon cancer has been predominantly a disease of those over 50.  Dr. Robert Ashley, an internist and assistant professor of medicine at the University of California, Los Angeles, has given more information concerning this much-feared disease.  Data has been warning for several years of a rise in colon cancers diagnosed before the age of 50.  JAMA Surgery looked at colorectal cancer data from nine states between 1975 and 2010 in a 2015 study.  The overall rate of colon cancer decreased during that time but only because the rate of colon cancer after the age of 50 decreased.  About 92% of the cases of colorectal cancer occurred after the age of 50, 8% before age 50 and only 1% occurred between the ages of 20 ad 34.  Also, the 35 to 49 age group experienced little change in the colon cancer rate, but in those ages 20 to 34 the rate of colorectal cancer cases increased by about 2% per year.

Researchers specifically looked at localized rectal cancers and sigmoid colon cancers in this younger age group.  According to their results the rate of these cancers had increased by 4%.  The increase rate of cancer in that age group was small because the total numbers of colorectal cancers in this age group was also small, however over the next 20 years the rates may continue to increase at the current rate and a large number of rectal and sigmoid areas might be diagnosed among those ages 20 to 34.

In 2017 a study looked at similar data from the same 9 states between 1974 and 2013 and found similar findings.  According to what they claim, the rates of colorectal cancers decreased in patients over 55 and decreased even more in those over 70.  Those aged 20 to 40 showed a cancer rate decrease between 1974 and 1985, but increased between 1985 and 2013.  Those ages of 30 to 39 had a rate increase of about 1% and those 20 to 29 had a rate increase of 2.4% between the years of 1985 and 2013.  The rate of colorectal cancers in this age range is low as the incidence increased from 1 in 200,000 people per year to 1 in 100,000 per year.

Perhaps the increase is due to the increased rates of obesity among young Americans that multiple studies confirm the correlation.  Colorectal cancer has been linked to decreased consumption of fruits, vegetables and fiber and an increased consumption of processed meat, which is characteristic of a modern American diet that happens to be reliant upon processed food.

Even though the rates of colorectal cancer in younger Americans are relatively low, the increased incidence in this age range is indicative of unhealthy habits that are among younger Americans.  Furthermore, if those habits don’t change we will most likely expect the colorectal cancer rates to keep rising.

Dr Fredda Branyon