Can mammograms miss breast cancer 5 years in a row?

Anything is possible: Usually if you had mammogram 5 yrs in a row it would detect something assuming it was done and read properly, but not all cancers are always seen on mammography.

Not likely: If you have dense breasts that are difficult to read with mammograms or a very slow growing tumor, it is possible but unlikely. It is important to combine a mammogram with a breast exam by your health care provider and your own monthly breast self exam. Make sure you are getting digital mammograms.

Yes: I'm not exactly sure what you are asking, but it is important to note that mammography is not perfect and it can miss cancer, especially when the breasts are dense. About 15% of cancers dont show on mamm.So if you have a lump, particularly if the lump is getting bigger, the fact that the mammogram is negative does not completely rule out cancer. And ultrasound, or possibly a biopsy, may be needed.