When they compare those who had CT exams to those who had no CT exams, those who had CT exams increase a chance of getting cancer in a lifetime by .072% according to the study by Havard Medical. But those who had multiple CT exams, ie. 5 times to 32 times, the chance increases to 2.7% to 12%.
It seems that 0.72% validates 1% chance which Dr. Berrintong mentioned in her talk. I will be careful with us interpreting numbers because there are so many parameters that affect coming up with the probability.
But when we consider that the chance of getting bladder cancer in a lifetime is 4% for men and 1.25% for women, 1% of getting cancer somewhere in a lifetime is the number we should not ignore.
As Dr. Berringtong pointed out the use of CT exam is much lower in UK than US.
The population of England is 56 million in 2018. The population in the US 322 million in 2019.
The number of CT exams done in England is estimated 3 million times / yr or 0.05 times per person per year.
The number of CT exams done in the US is 90 million times in 2019 or 0.27 times per person per year. It is 5 times more than in UK. I do not know the rationale of either country.
CT Scan manufactures are coming up with always with more expensive CT scanner with new features such
as more slicing for more detail image. One slice means one xray shot. 64 slicing CT sells about $1M and 320 slicing sells for $2.5M. Radiation dose of 320 slicing CT is 50% more than 128 slicing CT scan. It sounds like the lower number of slicing, the less radiation dose is. It is good to ask to whoever does CT exam how many slicing they use for our CT exam and what is the estimated radiation dosage.
Great read. Many of us have suspected the CT scan does involve some heightened increase to cancer. Of course as a diagnostic tool most of the time the benefits outweigh the bad.
Question, as I am sometime a little slow understanding things. "For the group as a whole, the increase in risk was slight — 0.7% above the overall lifetime risk of cancer in the United States, which is 42%. But for patients who had multiple CT scans, the increase in risk was higher, ranging from 2.7% to 12%." Is my math correct as I read 0.7% increase above a baseline of 42% of people having cancer and 2.7% to 12% above the 42%? Which computes to roughly 42% X 0.7%= 42.9% and 2.7% off of 42%=43.13% and 12% above 42%=47%? Sorry to be confusing I just wanted to quantify what I am reading. It is clear you don't want too many of these. Thanks.
DX 5/6/2008 TAG3 papillary tumor .5 CM in size. 2 TURBS followed by 6 instillations of BCG weekly with a second round of 6 after a 6 week wait.
Thank you so much for taking the time to share this information. I don't know how much I agree with it since, In the various literature on the topic that I have come across - pundits seem to say that radiation is really not the best as it makes the body more acidic.
In January 2013, Dr. Amy Barrington de Gonzalez - now Branch Chief Senior Investigator/Division of Cancer Epidemiology & Genetics / Radiation Epidemiology Branch at NIH had told the audience that the risk of developing cancer by the exposure to CT scan was 1% in a lifetime. She pointed out that the number of CT scans performed had increased from 3 million times in 1980 to 70 million times in 2007. She also predicted that the risk of developing cancer will increase to 3% if the CT usage continues to increase at the same pace. The number of CT scans performed had reached over 90 million times in 2019. So, the risk of getting cancer in a lifetime should have increased to more than 1%. So, I sent an email questioning to Dr. Barrington, and she replied that she and her team have been working on the subject and will be publishing the result. Dr. Barriton also pointed out that
the data from National Council on Radiation Protection and Measurements, which reports that annual non-therapeutic medical radiation dose to the US population in 2016 is 15-20% lower than it was in 2006. In 2006, the estimated average individual effective dose by CT was 1.46 mSv and it came down to 1.37 mSv in 2016 in spite the number of CT exams increased 20% from 2006 to 2016. I do not have access to the detailed report to find out the causes of the reduction. But I assume that the medical community and patients have become more aware of the risk of radiation exposure from CT. I also have noticed that there has been increased use of a low-dose CT scan.
In a 2009 study from Brigham and Women's Hospital in Boston, researchers estimated the potential risk of cancer from CT scans in 31,462 patients over 22 years. For the group as a whole, the increase in risk was slight — 0.7% above the overall lifetime risk of cancer in the United States, which is 42%. But for patients who had multiple CT scans, the increase in risk was higher, ranging from 2.7% to 12%. (In this group, 33% had received more than five CT scans; 5%, more than 22 scans; and 1%, more than 38.)
CT exam is fast, not expensive, and gives vital medical information as a diagnostic tool.
Also, as a consumer of CT exam, we should be aware that the more radiation from CT exams we go through,
the higher chance of developing cancer. We may want to keep a record of what type of CT scan we had, for example the whole body or just a specific area, and question to the doctor about the risk when the doctor orders us a CT exam.
Dr. Barrington de Gozales on Medical Radiation and cancer risk: assessing the price of progress