Manzoor, I also was diagnosed with a Stage III cancer.  My chances for survival without treatment were very low.  It's been 13 years since I completed the chemo, surgery, and radiation the doctors recommended, and I am doing fine.  Prayer and the support of my husband were important to me in helping me get through the treatments.  Of course, it is your wife's choice about what to do, but it would be helpful to talk with her to find out why she is reluctant to continue with the treatment.  She might also have a sister or other woman friend who can help her sort through her feelings.  Sometimes these things can be hard to discuss with a man, even a husband.  If she is feeling that she will go through all the pain of treatment and just die anyway, reassure her that medical treatment is her best chance for a long-term survival.

We can't tell you how long your wife is likely to live without more treatment.  Each Stage III case is different.  Her doctor will have the best estimate, but no one can ever know for sure.