Actually, if you stop drinking you’ll eliminate the risk of getting cancer from alcohol. That’s a fact. Not drinking any alcohol is the only way to avoid getting cancer from it. Same is true for tobacco.

Now, there are many things that can give you cancer, from environmental factors to genetic ones. So, there are a lot of things not under your control that may still give you cancer.

But if you want to, at least, eliminate the ones you can control, not drinking alcohol and not smoking are two good candidates. There are others, related to your diet that you can control (some related to red meats, for example).

From all I’ve read, there’s no safe level of alcohol intake. So, I became a teetotaler a few years ago. It’s not that bad. There’s are lots of alternatives that still allow you to socialize in a group that’s drinking. If you have any questions, just ask.

Edit: regarding what you ask, the effects are immediate. Same for tobacco. The sooner you stop, the better for your body. Now, you don’t drink much, but if you did, you’ll lose tolerance for alcohol pretty quickly. I can no longer tolerate alcohol, and I don’t even like the smell of it anymore. It’s actually pretty curious.