chemo is a dicey form of treatment. I’m familiar with the post-surgical treatments going back to the 70s, and the improved pre-surgical chemo cocktails that arrived after year 2k.
Regarding the 2nd hand smoke, not only is the concentration/ppm significant but also the general stress of the environment. For example, it may not be the smoke, but instead the interpersonal dynamics of the patient and the smoker. Or a combination of both. It would be interesting to know the related cancer rates that precipitated the chemo. There’s also the data dimension where the patient is isolated from the existing environment, and another dimension where the patient is isolated but also subject to similar particulates.
My experience with prostate cancer was all I ever want to have to go through. I researched the issue and decided on the Radiation. I worked in the industry for over 30 years and it didn’t frighten me. What I’ve seen with people I know and chemo does. The extra time if any it bought a close friend of mine with stage 4 colon cancer wasn’t worth the time and life quality he lost doing the chemo in my opinion. If he was still alive I would ask him. We all make our choices, hopefully they work out. Some don’t.