@simrin-- Actually radiotherapy is not really any better than chemotherapy when it comes to apoptosis. The truth is that all cancer treatments can and do cause damage to cells' DNA. And if the cells can't repair themselves, apoptosis becomes inevitable. That's a risk that comes with all cancer therapies.
And to some extent, we wish that all cells were that vulnerable to apoptosis. Some people actually have an apoptosis gene which prevents some cells from dying. This is a huge problem if that same cell is diseased and mutated. It's one of the problems that doctors are dealing with right now. This gene and these undying cells cause anti-cancer treatments to fail.
So apoptosis is a good thing. It's vital for us.