How often do mammography screenings detect breast cancer early?

Each year the Mammography Screening Program detects about 17,300 carcinomas. In other words: Out of 1,000 women examined, 6 women will be diagnosed with breast cancer.

About 13,300 of the tumours detected are invasive. That means malignant changes in the tissue which have spread to the surrounding tissue. The majority, so 80 percent of these tumours, are no bigger than 20 millimetres and haven't spread to the lymph nodes yet. These are tumours with a particularly positive prognosis. Gentler treatment methods can be used and there is a better chance of recovery.

Physicians in the mammography screening also detect so-called pre-breast cancer stages (ductal carcinoma in situ). They already consist of malignant cells. However, they are only growing within the milk duct, without any substantial tie to the vascular system, and do not form lumps yet. Pre-breast cancer stages typically can't be felt.

They can be very small but also extend far into the milk ducts without being noticed. Over time, a DCIS can turn into invasive breast cancer, which means cancer, which is growing into the surrounding tissue and becoming dangerous for the woman. About 19 percent of tumours detected through the mammography screening are pre-breast cancer stages (ductal carcinoma in situ).