The Impact of Regular Exercise on Colon Health & Cancer Survival

Colorectal cancer is the second leading cause of cancer related deaths in the US. The risk of developing colon cancer increases exponentially with age, with 90% of cases diagnosed in patients over the age of 50.

Researchers and physicians have recently confirmed what they have suspected for some time: Exercise may be a key way to ward off this disease. Exercise, even as little as one hour per week, has been proven to reduce the risk of developing colon polyps- the precursors to colon cancer.

While there are groups that are at higher risk for colon cancer, exercising decreases the risk in all demographic groups. "Exercise is a good thing," said Dr. David Weinberg, chairman of medicine at Fox Chase Cancer Center in Philadelphia. "It matters in sick people and black people and skinny people and overweight people."

Although many previous studies have been done on this subject, not many looked at the effect of exercise in a multi-ethnic group.

"African-Americans are disproportionately impacted by colon cancer. Even within our own sample, blacks had the highest prevalence of polyps and adenomas [benign tumors that can become cancerous]," said study author Dr. Nelson Sanchez, attending physician at Memorial Sloan-Kettering Cancer Center in New York City. "Overweight and obese people are another segment of the population that is at increased risk of colon cancer and colon polyps."

This study included almost 1,000 patients of different ethnic and racial groups: 56.8 were Hispanic, 20.6 percent were Asian, 15.2 percent were black and 7 percent were white. The participants were middle-aged and at no increased risk for colon cancer or polyps. About two-thirds were overweight and about half exercised for at least an hour a week.

After performing screening colonoscopies, the researchers determined that people who exercised one or more hours a week had a 25.3 percent risk of polyps, versus 33.2 percent for those who didn't meet this exercise threshold.

The hour of weekly exercise lowered the risk of adenomas in people who were overweight and who were black. The risk of cancer was also lowered in black study participants.

Another contributing factor to colon cancer survival is a gene called CTNNB1 (cadherin-associated protein beta 1), in relation to a patients BMI.  Obese patients (BMI ≥30 kg/m²) who were positive for nuclear CTNNB1 showed significantly better 5-year colorectal cancer-specific survival and overall survival compared with those with negative status (adjusted hazard ratio (aHR)=0.24 and 0.56, respectively).

However, positive status for nuclear CTNNB1 was not significantly associated with colorectal cancer-specific survival or overall survival in non-obese patients.

The study also found that a high level of physical activity (≥18 hours of metabolic equivalent tasks [MET]/week) post-diagnosis was associated with significantly improved 5-year colorectal cancer-specific survival in patients negative for CTNNB1 and cancer in stages I, II, or III (aHR=0.33 compared with patients engaging in <18 MET-hours/week). Among patients with a positive CTNNB1 status, however, there was no significant association between physical activity and survival.

Conclusion: Get up, get out, and get moving. It will positively impact your health in more ways than one, and can help ward off colon cancer.

Before beginning any exercise regimen, you should consult your physician. The findings of this study were released yesterday at Digestive Disease Week in Chicago, and should be viewed as preliminary until they can be published in peer-reviewed medical literature.

Sources: HealthDay Reporter Even a Little Exercise May Protect Against Colon Polyps Study found just one hour a week made a difference in risk  By Amanda Gardner; Exercise, BMI May Affect CTNNB1 Association With Colorectal Cancer Survival. MedWire (5/9, Grasmo)