In Sweden, all women of certain ages are regularly summoned to X-ray their breasts. The breast X-ray is called a mammogram. The examination is called screening. The purpose of screening is to detect any changes that may be symptoms of breast cancer. You can have breast cancer without noticing anything different. The chances of full recovery increase if breast cancer is detected at an early stage. Mammography screening is almost always able to detect early stages and precursors of breast cancer.
Some early cancerous changes will never develop into malignant breast cancer but it is impossible to know that in advance. That is why all early cancerous changes are regarded as being dangerous. So screening can lead to some people being treated for breast cancer even though they don't actually need it.
A mammography examination is a quick procedure. You do not need to make any preparations. Specially trained nurses will perform the examination and help you during your visit.
The Swedish letter you have received states the place and time of your appointment. Feel free to reschedule if you cannot make the appointment. Screening is completely voluntary. Don't forget to have an ID card with you. You are welcome to bring a friend or family member along.