Is stage 3 breast cancer usually fixable with an operation?

Yes. Stage 3 breast cancer is curable, but in addition to an operation most women will need chemotherapy and radiation therapy for the best chance of cure. Surgery removes the cancer from your breast/lymph nodes, but chemotherapy & radiation kills cancer cells that have escaped into your body. These escaped cells can return as incurable stage 4 cancer, so treating them is very important.
No. Stage iii breast cancer requires a multimodality approach to therapy using chemotherapy, surgery and sometimes radiation therapy.