Cancer is more expensive. If you're over 40 it's preventative and covered by most insurance.

One chemo treatment is ~$35,000 without insurance and you normally need 4-6 chemo treatments over the course of a few months. And they won't give you the chemo until you pay. My personal treatment plan was 6 treatments in 4 months.

A mammogram or colonoscopy is going to run you about $100 to $3000 without insurance once a year.

There is also many groups that will help offset the cost of getting the preventative exams. If you are really putting this off due to costs, DM me the location you are in and I will try to find a organization in your area that will help pay for the treatment.

EDIT: this is in the US, normal countries cover healthcare costs like this.