Dr. Sanjay Gupta

Well, the root cause of cancer are DNA mutations, which lead cells to grow out of control and then maybe spread to other parts of the body.

What alcohol does is it interferes with cell cycles.

It triggers long-term inflammation, and it damages DNA directly.

Alcohol can also affect hormone levels, including that of estrogen, which plays a particular role, for example, in breast cancer development.

Cells in our mouth can absorb cancer-causing chemicals, carcinogens, more easily when we drink alcohol.

So there's plenty of evidence in terms of the impact of alcohol on certain types of cancers, and even more and more information about the mechanisms that make it so.

But the question is, can quitting or cutting back bring it down?

Now, the headline is, studies show that cutting back on alcohol, going dry, can decrease the risk of cancer.

But it might take a while.

Let's begin with liver cancer, for example.

There was a study out of Sweden which found that if drinkers don't drink any alcohol, their risk of liver cancer goes down about 6 to 7 percent every year.

So the researchers estimated that it would take about 23 years of abstinence for a former drinker's risk of liver cancer to decline to the level of a never drinker.

I do just want to say that there is a fair amount of uncertainty with these numbers.

So think of these more as ballpark ranges.

It obviously varies individual to individual.

When it comes to head and neck cancer, researchers found that the increased risk of cancer of the larynx and throat caused by alcohol can be reversed.

Five years after abstaining from alcohol, the risk for those cancers fell around 15%.

But again, it would take more than 35 years to reach the same level of risk as a non-drinker.

For esophageal cancer, they found that, like with the other cancers mentioned, the increased risk of esophageal cancer is reversible by quitting, but it would take about 16 years to eliminate the extra risk produced by drinking.

But quitting does produce significant short-term benefits.