Tillmann T, Ernst H, Streckert J, Zhou YI, Taugner F, Hansen V, Dansenbrock, C. Indication of cocarcinogenic potential of chronic UMTS-modulated radiofrequency exposure in an ethylnitrosourea mouse model. Int. J. Radiat. Biol., Early Online: 1-13, 2010.
There is a great deal of public concern that continuous exposure to radiofrequency electromagnetic fields (RF-EMF) over a lifetime could cause adverse health effects. Cancer is thought to occur through a multi-stage process and RF-EMF fields are thought to promote this process, if an effect is real. Few studies have investigated the lifetime effect of continuous exposure to wireless telecommunication systems on tumour growth.
The objective of this study was to determine the types of cancer risk associated with a lifetime exposure to RF-EMF.
Five different treatment groups of mice were used in the study. Radiation exposure and/or ENU treatment began 6 days after pregnancy. When litters were born, up to three female pups were housed with their mothers until weaned, then the mother was removed and these female descendants continued exposure for up to 24 months. In certain treatment groups, the pregnant females were exposed to ENU (ethylnitrosourea) at 6th day of pregnancy; this substance initiates tumour growth in mice. Three groups were placed in the UMTS (Universal Mobile Telecommunications System) exposure device and exposed every day for up to 24 months. The first group was exposed to a high-level field intensity of 48 W/m2, a second group was treated with ENU and exposed to a low-level field intensity of 4.8 W/m2 and third group was not exposed to radiation (sham) or ENU treatment. There were two additional control groups used in this study that were left in their cages. One group was treated with ENU and the other group was left untreated. Two years later, tissues were examined for tumour growth.
The researchers found that mice that were exposed to high-level RF-EMF, sham-exposed, or mice left in their cages had around the same number of tumours. However there was a significant increase in the number of tumours seen in the lung of mice expose to low-level RF-EMF plus ENU treatment compared to mice treated with ENU only.
Interpretation and Limitations
This study demonstrated that early and continued exposure of RF-EMF could enhance cancer risk as long as an initial carcinogenic effect was given. It is interesting to note that lifetime exposure to high-level RF-EMF alone did not initiate any increased cancer risk suggesting that RF-EMF itself is not carcinogenic. Continued research is required to investigate what mechanisms are triggered in cancer and how RF-EMF could enhance this process.
This study suggests that lifelong exposure to RF-EMF is associated with an increased risk of lung cancer if other carcinogenic effects are experienced.