How nice of you to visit this site and ask this question. It's great to hear from a spouse! You don't say how far apart your wife's treatments are. I imagine she has blood work in between. For me, going out depended on a couple of factors: my white blood cell count (an indication of how compromised my immune system was), and how I was feeling. I got pretty addicted to hand sanitizer, so I'd take it along if you go out. As time went along I didn't feel at all like going out. My husband brought me take out from my favorite restaurants!
I'd put a phone call into her doctor to get his/her thoughts.