100% true.
No empirical scientific data exists that 'colon cleansing' does anything. Foo Foo science like alchemy, homeopathy medicine which is 99% water and those ridiculous detox diets of lemon juice fastings or whatever when your liver already detoxes everything.
If you want real empirical data look at Africa. They have 1 in 100,000 cases of colorectal cancer as compared to N. America which is more like 50-60 per 100,000. They simply deduced it was their insoluble fiber diet containing foods such as beans, avocado, greens, okra, yams and peanuts. There I just saved you whatever money they were going to charge you for an overpriced enema go spend it on a girl.
Eat moderate fiber. Excersize. Drink water. Avoid fructose and processed foods. Get all the regular cancer screenings if you're that age. Your liver and kidneys handle the rest.