RT - Chemo can be horrendous. It can cause a host of side effects as well as damaging the bodies immune system which can lead to potentially fatal infections.
Nobody pretends that chemo isn't extremely toxic. In my case it caused spasms of my aorta (cardiotoxicity) and almost killed me.
On the other hand, if it works it stops or slows down the growth and spread of malignant cells. Along with radiotherapy and surgery it saves lives. In other cases it extends life.
Sadly cancer cannot always be treated effectively. If it has already spread at the time of diagnosis then it is less likely that it can be cured. Patients must be fully involved in discussions with doctors and oncologists to assess the risks and benefits of possible treatments.
I totally respect those who decide that further chemo is not appropriate. On the other hand dismissing chemo and radiotherapy in the way you did above is dangerously foolish.