Dear Arzola, A neuroendocrine tumor refers to the type of cell that the tumor grows from, not the location of the tumor. Neuroendocrine cells produce hormones or regulatory proteins, and so tumors of these cells usually have symptoms that are related to the specific hormones that they produce. You would want to have your oncologist explain to you more about this particular type of tumor as treatment would be treatment of neuroendocrine carcinoma, not the same as that for breast cancer.
Trauma to an area does not cause cancer. It may be that where the underwire of your bra was rubbing, was already effected by abnormal cells and was a sensitive area.
trauma has absolutely nothing to do with forming the cancer. As to neuroendocrine cancer: it's hard to explain, but in a way it's not "breast" cancer, even though it occured in your breast. What I mean is that what we generally call breast cancer are those cancers that originate in tissues that are unique parts of the breast, namely breast glands and ducts. It's also possible -- and quite rare -- to get other cancers that start in the breast, but which originate in tissues that could be found anywhere in the body: nerves, muscle, blood vessels, lymph tissue. So what you have is a cancer that happened to occur in your breast but which actually grew from tissue that could have occurred anywhere. So the treatment will be different: it needs local removal, as you have had. Whether or not any other treatment would be recommended would be a decision based on the particular characteristics of the neuro-endocrine tumor you have, and would not be like what you generally hear for breast cancer.