What is metastasis ?

A metastasis is a secondary tumor site, originating from primary tumor cells that have become detached from it and then transported to nodes or secondary organs via the lymphatic and/or blood circulation. Breast cancer, whether it has pejorative biological characteristics, is likely to produce metastases.
The organs that may be secondarily affected are the bones, brain, liver, lung…..

The risk of developing metastases in the case of breast cancer depends on the molecular characteristics of the original tumor. According to several studies, aggressive, fast-growing breast cancer, which rapidly becomes large and metastatic from the outset, does not develop from every small lesion, but from a subpopulation of small lesions with biological factors that are pejorative from the outset.

Since being detected, the rates of metastatic cancer have not decreased over the past 20/30 years, although this is one of the objectives of screening, together with the decline in mortality.

Read: https://cancer-rose.fr/en/2020/12/17/mammography-screening-a-major-issue-in-medicine/