24th August, 2010
While colon cancer rates have remained steady over the past several decades among people under the age of 40, a new analysis has found that rectal cancer rates are increasing in this same population across races and in both males and females.
Rectal cancer usually develops at the rectum, the point that links the large intestine with the anal canal for passing faeces.
It develops over several years, first growing as a precancerous growth called a polyp. Some polyps have the ability to turn into cancer and begin to grow and penetrate the wall of the rectum.
The actual cause of rectal cancer is unclear. However, the following are risk factors for developing rectal cancer: increasing age, smoking, family history of colon or rectal cancer, high-fat diet and/or a diet mostly from animal sources.
Though the cancer may be present without any symptoms, experts say some of the symptoms to be aware of include the following: continuous bleeding, obstruction of the rectum causing constipation or pain when having a bowel movement.
While a person suffering it may experience pencil-thin stool and weight loss, a sufferer may also have a sensation that the stool cannot be completely evacuated after a bowel movement.
The study further shows that greater efforts are needed to diagnose rectal cancer in young individuals who show potential signs of the disease.
The report was published yesterday in the Cancer, a peer-reviewed journal of the American Cancer Society.
The researchers who studied the disease and how it has spread said they embarked on it because underestimating the disease incident may lead to missed or delayed diagnoses in younger people.
Joshua Meyer, MD, a radiation oncologist currently at Fox Chase Cancer Center, led a team that analysed trends in the incidence of the disease in the United States compared with colon cancer trends.
Dr. Meyer worked on this research while at the New York-Presbyterian Hospital/Weill Cornell Medical Center in New York City.
Using data from the Surveillance Epidemiology and End Results (SEER) cancer registry, the investigators identified 7,661 colon and rectal cancer patients less than 40 years of age between 1973 and 2005. The researchers then calculated the change in incidence over time for colon and rectal cancers.
The researchers found out that while colon cancer rates remained essentially flat in individuals under age 40 in recent decades, rectal cancer rates have been increasing since 1984. Specifically, between 1984 and 2005, the rate of rectal cancer diagnosis rose 3.8% per year.
“We suggest that in young people presenting with rectal bleeding or other common signs of rectal cancer, endoscopic evaluation should be considered in order to rule out a malignancy.
“This is in contrast to what is frequently done, which is to attribute these findings to hemorrhoids. More frequent endoscopic evaluation may be able to decrease the documented delay in diagnosis among young people,” he explained.