One day in the not-too-distant-future, doctors could be curing cancer with a $5 injection. It might sound far-fetched now but researchers at Duke University have successfully treated oral cancer in mice using ethanol injections. Within eight days, the mice were tumor-free.

Using alcohol to treat cancer isn't new. Ethanol ablation (a therapy where pure ethanol is directly injected into a tumor growth) is used to cure specific types of liver cancer. It has similar success rates as surgery but it comes at a much cheaper price tag – it costs just $5. 

But it also comes with limitations. One problem is that it involves a large volume of ethanol. This means there's a high risk the ethanol will leak into and damage the surrounding tissue, so it can only be used to treat certain types of tumor (say, liver cancer).

To get around this problem, the researchers mixed the ethanol solution with a chemical called ethyl cellulose. This turns the solution into a gel as soon as it is injected into the tumor, preventing leakages and making sure it remains concentrated in the cancerous area.

The injection was then given to hamsters with cheek cancer. Within seven days, all but one tumor had disappeared. By the eighth day, all seven tumors were gone. This gave the experiment, published in the journal Scientific Reports, an incredibly impressive 100 percent success rate.

Compare this to the control group, where the hamsters were injected with pure ethanol. The researchers only noticed positive results after injecting large volumes of ethanol. Even then, only a third of tumors had disappeared by day eight. 

While the results are extremely encouraging, it is still only an early proof-of-concept trial and further trials with larger sample sizes – not to mention humans – will be needed before it goes on to have a real-world use. 

Even then, it is likely surgery will remain the first course of action in places like the US and UK. The real benefit of ethanol ablation will be seen in developing countries, where medical supplies and personnel are in short supply. Nine out of 10 people in the developing world don't have access to surgery so a safe, portable, and cheap noninvasive alternative would have huge life-saving consequences.