I had only one positive lymph node, a lumpectomy and was estrogen positive. I opted for chemo and radiation. My test numbers were good but with full treatment I got my percentages up to 98-99% for no further breast cancer. Once it travels in your system, you might have doubts. As they docs say, they can't see microscopic specks so you have to gather all the information and think hard on what you will feel comfortable with.
This is a very personal decision and only one you can make with your doctor. I knew that if I didn't do everything I could to eradicate this disease I'd kick myself every time I felt a twinge. I figured one crappy summer was worth a lifetime of good ones. I wish you the very best with whatever course you take.