From the article:
Dr Andreas Stang, who led the research, said he had
examined 118 people with uveal melanoma and obtained
details about their use of digital mobile phones. This was
compared with a control group of 475 people without the
To prevent bias, the researchers were not told if the
person they were examining suffered from cancer or was
healthy. When the results were analysed they found the
cancer victims had a much higher rate of mobile phone
use, though Stang cautions that his study needs
As the writeup suggests, the study is apparently only correlational and thus is statistically meaningless with respect to causality. IMO such non-experimental studies are so flawed that they essentially add nothing to the debate about whether X causes Y, and they can be even be harmful by suggesting incorrect conclusions.
Because the subjects were chosen after they developed cancer, there is no statistical way to determine the cause. More convincing would be an experiment in which certain subjects were randomly asked to use cell phones and then studied for side effects. But for now, the fact that cancer patients are more likely to be cell regular phone users could be due to the fact that, say, cell phone users are generally wealthier, and thus more likely to own computers, which are (hypothetically) the true source of the eye cancer. Or one of myriad other variables that might contribute to the cancer.
Nor is it a question of "how much correlational data is needed" to establish causality. Hundreds of different studies might conclusively establish a "link" between cell phone use and cancer, but that wouldn't be any more convincing. Even assuming that correlation exists does not lead to the conclusion that there is causality.
Of course it could be pointed out that, as the article says, cell phones have been shown to "temporarily alter the workings of the brain". Don't such findings provide an explanation for the correlation found in the study? Perhaps, but the study hasn't really strenghthened the evidence we had before. It leaves us with the same conclusion--we can surmise that cell phone use causes cancer, but there is no strong evidence.
So I think that the news of a link between cell phone doesn't change the answer to the question of whether cell phone use causes cancer: we still don't know. It's important to point out that (AFAIK) there is not much evidence that it does not cause cancer either. Unfortunately, until we have more convicing data, our frightening ignorance about the effects of cell phone use (as well as many other common parts of our environment) will continue.