Spot on lung after breast cancer

About 2 years ago my sister was diagnosed with breast cancer.  She was pregnant at the time and was forced to have a c-section to have the baby early, about 12 weeks.  I'm happy to report that the baby is perfect, no ill effects whatsoever.  My sister has been fine until a recent inquiry about a gall bladder problem.  Upon the CT Scan, the Dr. noticed a "nodule" on the right lung.  This was the side of the breast cancer as well.  She goes to the oncologist today for preliminary work, and most likely later this week for a biopsy, if he deems it necessary.  She was treated for the breast cancer with chemo as well as radiation.  My question(s) is this:

Could this possibly be scar tissue from the radiation?
If it is cancer, what are the general survival rates?  She is 30 yrs old and the new spot is said to be only one nodule.
What is treatment like for the forementioned?

Sorry for the long post, I could just really use some piece of mind.

[CCF-RN,MSN-rf]

Dear TRoub:  It is nearly impossible, without viewing the scan, to say how suspicious or not this "nodule" looks.  In situations such as your sister's, if this has not been noted on earlier scans, there would be a low threshold for investigating a new finding.  If this is cancer, it represents metastatic disease, which may be considered more of a chronic disease with which one lives - sometimes on treatment and sometimes off.  Survival depends upon how the disease behaves and how it responds to treatment.  Generally speaking women with breast cancer can live for years.  Treatment will depend on the extent of disease but may likely include chemotherapy.