Occupational radiation exposure linked to left-sided brain tumors

Lloyd W. Klein, MD

This is an extremely important paper and one I believe most hospitals and societies are going to try to bury. The findings fit into the category of occupational health and when you identify risks to working in a workplace, whether it's the coal mine or the cath lab, you step on all kinds of financial and egotistical feet. That is what we found in the Multispecialty Occupational Health Group: the more you go into health impact and incidence of lost time from work, the less anyone really wants you to look at it. The X-ray manufacturers don't want you to look at it because it's their design, and if you start criticizing their design, it's going to cost them money to redesign their equipment. The hospitals don't want you to look at it because they depend on young people to keep being trained as middle-aged people keep going out with health problems. And training programs don't want to talk about it because they need to train young doctors to do the same thing as the old doctors are doing. So you have a situation here where no one wants to hear the problem. And this paper really points out the consequences. Although the paper in itself does not prove anything other than identifying a cluster of cases, when you put it together with many other studies on occupational hazards, they tell a very startling story.

One of the aspects of the study I find most interesting is that cath labs and radiology suites are designed for the doctor to be on the patient's right-hand side, and so the radiation source is toward the left side of the brain; the fact that these cases are nearly all on the left side parallels the fact that the left side of the brain is being exposed the most. So, not only is this study telling you there is a clustering and there is a hypothesis to suggest why, but the sidedness strongly supports that hypothesis. So I think this is a very scary, concerning and troubling paper that everyone in health care should be talking about it. Yet the silence will be deafening.

Dheerendra Prasad, MD, MCh, FACRO

In their carefully documented series, Roguin and colleagues raise two important points: The incidence of primary brain tumors — especially glioblastoma — is worrisomely high, and the incidence of left-sided tumors is disproportionate. Not having a precise denominator of the number of specialists exposed makes it difficult to come up with an incidence rate. However the left-sided preponderance beats any statistical odds.

In the post-radiotherapy setting, gliomas arise with a reported 2.5% incidence at 15 years (Tsang RW. Cancer. 1993;72:2227-2233) and a relative increase in incidence of 2.6-fold vs. patients never irradiated (Ron E. N Eng J Med. 1988;319:1033-1039). The average latency of these tumors can be 9.2 to 11 years (Kaschten B. J Neurosurg. 1995;83:154-162. Nishio S. Acta Neurochir (Wien). 1998;140:763-770). No side or sex predilections are reported in literature. Despite the fact that the current paper refers to low-dose exposure, the findings are cause for a thorough review and perhaps a registry for such cases.