Monday, December 21, 2009


I have always been very concerned about the uncontrolled, proliferation of MSCT scan machines in the country in general and the Klang Valley in particular. Two recent clinical papers in the 14th Dec 2009 Archives of Internal Medicine, highlights the cancer risks with widespread use of the MSCT scans.I will use the titles directly and they will be self explannatory. The first paper by Drs Smith-Bindman R, Lipson J, Marcus R, et al. entitled "Radiation dose associated with common computed tomography examinations and the associated lifetime attributable risk of cancer." Arch Intern Med 2009; 169:2078-2086. The second is by Dr Berrington de González A, Mahesh M, Kim KP, et al. entitled " Projected cancer risks from computed tomographic scans performed in the United States in 2007. " Arch Intern Med 2009; 169:2071-2077. As you can see, in 2007 across the US, about 57million scans were performed, and now we have a 2 year follow-up. The research shows that 29,000 cancers occurred in the patients who were scanned. There were cancers of various types and affected particularly the young females. For some reasons, females were more prone. They also discovered that the same institution doing scans had different doses, even for the same kind of scans. Looks like there is almost no standard dose.
I suppose what I am trying to say is that scans done must be for a good reason. The benefit from the information must outweigh the cancer risk from the scans. Routine scans cannot fit into this category and there the risk outweighs the benefit. There are risk from the scans. They are not innocent. When we first started to alert the public, many cardiologist were upset with us ( even till now ). But they have taken heed ( grudgingly, I suppose ). I understand that nowadays, there is more explanation regarding cancer radiation risk. To be fair, the current generation of scans, especially the latest 256 slice MSCT has much less radiation and can scan the whole heart in one heart beat, thereby reducing radiation. Of course, it is more expensive.
The other issue with widespread use of the MSCT is that, many innocuous small nodules are picked up incidentally, resulting in many unnecessary surgical biopsies and additional procedures, thereby increasing cost and risk. Not to mention the many sleepless nights for the subject, once he is told that he has a ?" lung nodule ".
Basically, I would like to emphasize that whatever tests we order, the benefit from the information derived from the test must far outweigh the risk of the test. Else, the test should not be done and something less risky should be prefered.

No comments: