anyone have invasive secretory melanoma

My doctors say this is a rare breast cancer and so they are treating me differently than other more common breast cancer patients. I had a lumpectomy in May 2010 with no lymph node involvement, my tumor was .90 and am now having radiation treatment, have 2 more weeks to go. My onco score was 28 which in other cancers would have meant chemo but they are saying that because my cancer is rare the studies were not including my type of cancer so they are opting out of chemo for me. They say the cancer has a good prognosis of not returning so that is why they made that decision. I will be going on Arimadex after rad. is completed but wondered if anyone else has this type of cancer. They tell me in this case it was good to be rare. Still in the back of my mind I am wondering that if it's rare that would mean they don't know much about it and perhaps it will act in ways they cannot predict.

Guess it's my own paranoia but I want to take no chances of having to go through this again.

Rosey