Colon cancer is more common in males than it is in women, and this is well known. However, established risk factors like food or lifestyle may explain these gender-specific variations only in part, as research has recently revealed. For the time being, it is unknown what additional factors make males more vulnerable to colon cancer. Hormones may have a more significant impact than previously believed.
Colon cancer is one of the world's most prevalent cancers. Overall, the lifetime risk of developing colorectal cancer is about 1 in 23 (4.3%) for men and 1 in 25 (4.0%) for women—several other factors. Smoking and excessive intake of red meat are among the risk factors. Both are more prevalent in males than in women. In studies, scientists have also discovered the first signs of hormonal effects on colon cancer development in fruit flies.
The extent to which known risk and preventive variables may explain the variations in colorectal cancer risk between men and women is still unclear.
A team headed by Tobias Niedermaier of the German Cancer Research Center (DKFZ) in Heidelberg has now reviewed data on almost 16,000 men and women aged 55 and 79 who have undergone colonoscopy for colon cancer prevention.
"We considered the following risk factors," the researchers write, "age, family history of colon cancer, diabetes, previous colonoscopy, aspirin, and statin use, smoking, alcohol consumption, body mass index (BMI), height, physical activity, consumption of red and processed meat, fruits and vegetables, and whole grains, and finally, use of hormone replacement therapy."
The risk variables alone cannot explain the rate of cancer.
A colonoscopy showed 141 males (1.8%) and 78 women (one%) who have colon cancer. An additional 1,049 males (13.4 percent) and 591 women (7.2 percent) had an advanced bowel adenoma, a tumor that is generally benign but precancerous. Men have been afflicted almost twice as frequently as women in both colon cancer and advanced adenomas.
The degree to which risk and protective variables gathered may explain this distinct distribution has now been estimated by Niedermaier and his colleagues. "Many risk and protective variables vary substantially between men and women," stated the researchers. "For instance, more males had diabetes, were smoked, drank more alcohol, were more overweight, had fewer workouts and ate less nutritious foods."
All these variables, adjusted by age, may explain 47 percent of the higher men's risk. "This implies that we still do not know the source of the other half of this extra risk," said Hermann Brenner, Niedermaier's colleague.
Hormones may be more essential than anticipated.
Where might the explanation lie, however? Female hormones may be a previously overlooked protective element. "In comparison with women never receiving hormone replacement treatment, men's risk was lower than that of women receiving hormone replacement therapy," researchers stated. "This indicates that hormonal variables play a significant role in the risk of colorectal cancer and this may to some part explain the residual increased risk to males."
To take this aspect further into consideration, data on pregnancy, birth control pills, breastfeeding, and the beginning and end of menstrual cycles are recommended for future research to be collected. 'The rest of the gender difference may be explained by a greater knowledge of the function of the hormone variables throughout life,' the researchers write.
Early diagnosis - particularly for males - is essential.
An accurate understanding of each risk factor may also assist in the choice of early detection offers. "Our findings reveal, however, the importance of using the choices for colorectal cancer screening, stomach testing, or prevention, particularly for males," adds Brenner.
Source 2: Key Statistics for Colorectal Cancer