I know you are worried. My husband seemed to take my diagnosis harder than I did. In the 2 months since then, he has been with me at every appointment and procedure.
Breast cancer is usually not painful. It's a good thing you have a follow up planned. Breasts develop calcifications as we age - it's normal. On a mammogram, they are usually tiny bright white round "pearls" scattered around the breast. Radiologists look for calcifications that are oddly shaped or close together. They compare current and previous mammograms as well. Many women have quite dense breast tissue which makes it harder to see these changes.
Most of the time when they see something that isn't clear to them, they ask for a second mammogram that will magnify the area of concern. Ultrasounds are not as commonly used but are certainly helpful. Most women will have a biopsy next. Today a stereotactic breast biopsy is done. They give you a little lidocaine that stings a minute, but that's it. I found it completely painless. The incision is tiny, 1/3", and closed with a steri strip. I had 12 areas of concern in one area so they took 12 tiny samples and found cancer is 8 of them. That means that 4 areas had no cancer at all even though they looked like the other ones. That's why they need the biopsy...to make sure. Lot's of women have a completely negative biopsy and your wife could be one of those.
The pathologist will check the biopsy samples and if they find cancer, they will identify the kind and stage of development. Mine was small and confined to a duct in my breast, DCIS, stage 0, but identified as an aggressive type. The usual treatment for that kind of cancer if a lumpectomy, where they take out the tumor and some adjacent tissue, followed by radiation. Chemotherapy might be added. She will likely be given hormone therapy, Tamoxifen, for 5 years afterwards. All that sounded awful to me, so I chose a mastectomy. No radiation or chemo would be needed. I took it one step further by choosing to have the other breast removed as well. I decided I didn't want to deal with worry that the cancer would come back or show up in the other breast.
I also chose immediate reconstruction which was done via by a plastic surgeon right after the general surgeon was finished with the double mastectomy. Implants were placed. Not all women are candidates for this and have tissue expanders placed instead. Weekly saline injections slowly expand the tissue so it can accommodate an implant a few months later.
Some women do not want to lose their breast so they would never make the same decision as I did. There is no right or wrong. Every woman is different. Let us know what happens.