The Danish Cancer Society is reporting that the number of men diagnosed with glioblastoma —the most malignant type of brain cancer— has nearly doubled over the last ten years. Hans Skovgaard Poulsen, the head of neuro-oncology at Copenhagen University Hospital, is calling it a "frightening development."

The society is not linking the increase to cell phones or to anything else. "We have no idea what caused it," Poulsen said in a statement issued by the Danish Cancer Society on November 2. (See the June 2, 2014, update below.)

Both the Interphone study and the group led by Sweden's Lennart Hardell have reported that long-term cell phone use is associated with higher rates of glioma. (Glioblastoma is a type of glioma.)

"I think the data is true and valid," Christoffer Johansen of the Danish Cancer Society told Microwave News. Johansen is a member of the team that has been working on the Danish cohort study, which has been investigating the possible links between cell phones and brain tumors. The group has long maintained that there is no association. (For our analysis of the Danish cohort study, follow this link.)

Like Poulsen, Johansen did not offer any explanation as to what may have led to the increase.

Joachim Schüz, who used to work at the Danish Cancer Society and is now with IARC, could not be reached for comment. Schüz and Johansen were members of the Interphone project and work together on the Danish cohort study.

Schüz has long said that he does not believe that cell phones present a brain tumor risk. One of his main arguments against an association has been that national cancer statistics have stayed relatively stable.

This morning, we heard from Joachim Schüz, who is travelling in Asia. He tells us that the news about the increase in glioblastoma is “indeed a concern.” Like Johansen, Schüz does not have an explanation for what may be responsible for the uptick in these aggressive brain tumors, but he does not believe that it is because of better diagnostics.

Schüz added that he sees “no reason to question the quality of the Danish cohort study.”

The Danish Cancer Society has removed the original 2012 news advisory noting the spike in glioblastoma from its Web site. (The original link is now “404”). It is still available, however, from the Internet Archive’s “Wayback Machine”. Here is the news advisory as it was first posted by the society. If you open this link in Chrome, Google will automatically translate the page into English.

See also our follow-up article:

“Something Is Rotten in Denmark.”