Which cancer has better prognosis?

My sister, aged 46, has two very large lumps under her arm. She has had a negative mammogram done. One of the lymph nodes is around 15cms in size. Ultrasound has shown venous flow, a more round shape and defined edges. She is awaiting further tests - biopsy, CT scan, PET scan. All in all it doesn't sound good. As a non medical person but with "google" i have guessed that it might be occult breast cancer (which gets staged to 3 by lymph node involvement) or Non Hodgkins Lymphona. Neither is good. Her otherwise health is good, no other health issues at all. Could the cancer specialists out there in Yahoo Answer land give me an opinion on what cancer has the better prognosis? She has 2 kids, one is 9 the other 3. She thinks she will be dead in under 5 years. Statistically I think she has around a 60% chance of making 5 years. Any thoughts? Obviously nothing s known until we get all the test results but the chances of it being benign seem slim to none. Tragic.