The only existing reality regarding cancer, theists need to be educated about, is that there is no agent pulling strings to use it as a form of punishment or to "test believers" so that they "can glorify god". Cancer does not discriminate. It just strikes. It has no purpose. Does not serve any purpose. It affects millions each year and among those millions so many will meet a terminal prognosis. Others keep fighting, prolonging their remission with the "hope for a cure" being what motivates them to keep fighting.
Each time I have undergone treatments, I shared the treatment room environment with strangers I know nothing about. And it really does not matter to me what kind of person they may be. The only thing I feel and think is : they are my fellow human beings who experience what I experience as a cancer patient. They all have the same moments of fear, the same moments of discouragement and moments of hope as they "graduate" from their treatments and are given a good prognosis...for a few more years until a relapse. And also the same moments of valuing things we did not value before. Of not taking for granted any longer what we used to take for granted.
We share in common our humanity while branded with an illness which can either bring the best out of us or take us down to the level of considering "but...but I have been a good person and I got cancer!" or " well , he/she deserves it".