Dear Catalinamatalinewhoopastiea: Based on the information you provided, this sounds like a situation in which the breast cancer has reoccured or come back. In this case, I believe C4 describes a node that is positive for breast cancer. Lymph nodes are labeled by location. In this case, I think C stands for cervical - meaning the neck - and 4 is which node in the neck. You might check with the doctor to be sure I am interpreting your information properly. It is impossible to comment on prognosis in this case.
prognosis depends on several bits of information, including size of tumor, hormone status, etc. C4 may not be an accurate or complete term. The best info, in any given case, will be gotten from your doctors who know all the details. Even then, prognosis is a concept based on data from thousands of people; in an individual case all things are possible. So the best thing is to go into treatment with a positive attitude, because the majority of women with breast cancer end up cured; and even when not cured, long-term survival is possible in practically any situation.