Sorry you've got this worry going on, especially as you have family experience of it.
Lumps can be all sorts of things, most of them not cancer. Mammograms will show them up but it won't always be obvious from a mammogram what the lump is so I imagine they will either want to do further scans or do a biopsy. Obviously they will want to rule out cancer if possible so don't worry if they want to do a biopsy, tests are as much for ruling things out as ruling them in.
Even where families have a strong history of breast cancer there often isn't a genetic link found so while it's hard try not to see your situation as in any way related to what others have gone through. Just because they've had it doesn't mean you will have it. In terms of genetics it's more about age of onset etc. than necessarily the number of people affected (although that comes into it obviously). Have you ever been offered genetic screening? It might be worth asking about it if you do think there is a link as they would analyse your family history to see if tesing is warranted. I have been tested even though we only have two cases of breast cancer in our family (my mum and I), the testing was warranted because both of us were diagnosed in our early 40s and, in my case, I'll have likely had it since my mid-late 30s as I wasn't diagnosed until stage 3c. Ours did come back genetic but that is without a strong family history, so things are not always as they seem, sometimes it's just bad luck and/or environmental influences.
When is your appointment? Hope it all goes smoothly. Let us know how you get on?
