Cancer treatment is different. We have a high tolerance for side effects because many cancers are aggressive and deadly. It's a risk-analysis. If your odds of dying from cancer in the next year are 50%, and the drugs have a 25% chance of killing you, then the drugs are worth it.

In actuality, even extremely aggressive therapies like high-dose chemotherapy with stem-cell transplant have shockingly low risk of death. Less than 5%. Bear in mind, that's for a therapy that literally wipes out all of your bone marrow. You know, the part of your body that produces your blood? Your body stops making blood and your immune system. And yet, we've gotten the death rate as low as it is.