DCIS is a pre-invasive stage of BC, this is what you had. If not treated is moving to the invasive stage and it can be called LABC-locally advanced breast cancer and this is what I had.
My stage was 3c to 4a because of the tumour size 13cm x 8cm and 2cm armpit, so following your comparisson things looked far worse.
My type of cancer was HER2+, ER+/PR+ and I had what is called PCR patologic complete response follwiing neoadjuvant therapy. For some cancer types 60% of women have PCR. My chance rating was 10-20% , maybe little but it was an available option before I decide to remove my organs.
In Europe is a great medical campain to decrease the number of mastectomies and advise breast preservation because it's proven with clinical studies that neoadjuvant treatments improved a lot and yet it doesn't happen to the despair of patient-commited doctors.
I had no clue of all these when I was diagnosed, I was lucky to have the book "BC-Taking Control" which gave me enough to start doing more research. Keeping corectly informed and the mind open, this is what taking control means.
