Chloe, I saw your post in the other thread and thought a new one on this topic may help you.
Being as informed as possible is the best way to go in this scenario, as it is not an easy choice for many.
You asked how the decision is made and why some wish they had done a mast instead of a lump. Take caution to not act on emotion, but on facts and what is right for YOU.
Some people are not offered a choice, based on the kind of cancer, location, extent, etc. Regardless of whether they offer you a choice, I would highly recommend a second opinion...to either offer more options or cement the deal.
Factors are many. Some people cannot do radiation tx due to distance from the hospital so they choose a mast. Some people want to be as aggressive as possible. Others just "want it off". Others have high risk of other cancers or are at high risk for recurrance and choose to have a mast and a prophylactic mast on the other side to keep chances for recurrance as low as possible.
Keep in mind a mastectomy is permanent. You cannot reverse it, but you can always get a mastectomy at a later date if desired.
Many of us find that life after cancer, trying to regroup and get a new normal, is not so easy....and people want to take control as much as possible, and have the mast or bilateral mast later.
In my case, I was just barely 31, and could not even imagine getting a mastectomy. Several docs concurred that I had "equal chances for survival" with a lumpectomy, so I opted that route. A mastectomy would probably protect me better from a recurrance later...when I presented this to my doctors a year or so after treatment, they suggested it was "overkill" and cautioned me about making a decision based on fear.
Everyone has valid reasons for their choices. The key is that we do have choices in this process. Take time to get the facts and make your best choice....
Hugs,
Lori