09/10/2012 05:20 pm ET

Sheryl Crow Suspects Her Cell Phone Caused Her Benign Brain Tumor -- But Is It Possible?

Sheryl Crow suspects that the benign brain tumor she was diagnosed with late last year was caused by cell phone use, People magazine reported.

Crow said on the new talk show Katie that doctors have not told her that her tumor was caused by cell phone use, but she has "the theory that it's possible that it's related to that. I [used to spend] hours on the old archaic cell phones," People reported:

Crow, who says the tumor is in a part of her brain near where she often held her phone, says she started to suspect something was wrong when she began spacing out on stage, forgetting lyrics and generally feeling "mushy."

But is Crow right? Is it a fact that cell phones can cause cancer?

According to numerous studies and even an official classification from the World Health Organization: We're not totally sure.

The WHO's International Agency for Research on Cancer said last year that cell phone radiation is "possibly carcinogenic," meaning that cell phone use might be associated with brain tumor risk, specifically for glioma.

"The evidence, while still accumulating, is strong enough to support a conclusion and the 2B classification," Dr. Jonathan Samet, a scientist at the University of Southern California who chaired the working group, said in a statement.

HuffPost's Catherine Pearson reported earlier that carcinogens are classified by degrees by the IARC. Cell phone radiation shares the 2B degree classification with lead, truck exhaust, DDT and chloroform.

However, a sweeping study that came out in the American Journal of Epidemiology after the WHO classification did not show a link between cell phone use and benign brain tumors.

A study of nearly 3 million Danish adults showed that those who used a cell phone for more than 11 years were not more likely to develop a noncancerous brain tumor, called an acoustic neuroma or a vestibular schwannoma, than non cell phone users, or people who only recently started using a cell phone. Even though acoustic neuromas are noncancerous, scientists say they are still important in determining whether there is a cancer risk from cell phones, Reuters reported.

And even more, tumors were not more frequent on the side of the head where the cell phone was most commonly used, nor did the tumor size have anything to do with the amount of cell phone use, according to the study.

However, the researcher of that study -- who also happened to be from the WHO's IARC -- told Reuters that the long-term cell phone users in the study hadn't been using the devices long enough to say a cell phone-cancer link is impossible.

Multiple other studies have also shown conflicting results, with some suggesting a slight increased risk of brain tumors from cell phone use, and others finding no association at all.

So what's a person to think?

Dr. Timothy Moynihan, M.D. perhaps puts it best in this Mayo Clinic article:

For now, no one knows if cellphones are capable of causing cancer. Although long-term studies are ongoing, to date there's no convincing evidence that cellphone use increases the risk of cancer. If you're concerned about the possible link between cellphones and cancer, consider limiting your use of cellphones — or use a speaker or hands-free device that places the cellphone antenna, which is typically in the cellphone itself, away from your head.