Hi
Writing as someone with MTNBC, I would guess that it’s the nature of the cancer, not the small area, that’s at issue here. Your friend has been very fortunate to have had 17 years cancer-free but triple negative cells are very resistant and very aggressive. While there is just a small site, and they hopefully have secured clear margins, chemotherapy is the best chance of hitting this hard, thus reducing the likelihood of it spreading to other parts of the body - something nobody wants.
There are many types of chemotherapy but, despite its awful reputation, it’s not always as bad as one expects. It’s definitely manageable and there are all kinds of precautions to reduce side effects. The important thing is to kill off any rogue cells now, before they find a new home. Meantime, I’d say stay off Google, both of you, and if you want to know more about TNBC, use reputable sites like this one. Most material about TN is outdated, some is downright alarmist, so it’s best avoided if you want peace of mind.
I hope your friend’s treatment goes well and she has many more years cancer-free. It really is worth the effort (though it’s not always easy).
Jan x