If you had the choice of no cancer ever but with the chance of going mad, would it be worth the risk?

Say in the near future medicine by way of super gene construction makes an anticancer pill. You take it like a vitamin each day and you will never contract cancer of any kind, liver, lung, heart, pancreatic, colon, prostate, breast cancer; nothing. However, the effects of the protection wear off 72 hours after your last dose, but to take it everyday over 180 days places you at a 2 out of 7 chance of going mad, dementia that you will never be cured of even if you stop taking the pill, would the risk of avoiding ALL types of cancer be worth it to you?