Three Game-Changing Studies for Imaging in Sports Medicine
Three Game-Changing Studies for Imaging in Sports Medicine
Three landmark papers from Lancet and BMJ published in the past year have confirmed that the theoretical increased risk of cancer does bear out in follow-up studies. Pearce and colleagues' study in Lancet looked at the excess risk of leukaemia and brain tumours for children and adolescents exposed to CTs. They found that children exposed to cumulative doses of 50 mGy (3–5 CTs) may have triple the risk of leukaemia, and doses of 60 mGy may have almost triple the risk of brain tumours. Though this appears to be a very large increase in risk, the authors point out that these cancers are still relatively rare, causing an estimated one excess case of leukaemia and one excess brain tumour per 10 000 head CTs. Moreover, although not specific to the discussion of paediatric patients, the lifetime cancer risk of developing cancer in the general population of 1 in 3 needs to be considered. Nonetheless, the importance of this effect is emphasised by the fact that 12 other groups from 15 countries are studying the risk of scans on children.
The Pijpe et al GEN-RAD-RISK paper published recently in BMJ. This study showed that when women who carry a specific mutation associated with breast cancer (BRCA1/2), and who were exposed to diagnostic radiation before the age of 30, had almost twice the risk of breast cancer (with a dose–response pattern). This study involved lower doses which we had previously considered to be fairly 'safe' (eg, 4 mGy from a single mammogram or shoulder x-ray). Therefore, BRCA1/2 carriers, with an already increased risk of a very common cancer, would be particularly at risk from exposure from radiating scans at a young age.
Most recently, the Matthews et al Australian data linkage study, with an enormous cohort (11 million) showed that the adjusted overall cancer incidence for young people exposed to a CT scan was 24% greater than for those who were not exposed. That is, one in every 1800 scans resulted in an excess cancer case. The relative risk was higher for many different types of cancers and exhibited a dose-response relationship. This is particularly striking as the mean follow up time was 9.5 years, suggesting the true lifetime risk may be much higher. The researchers assumed a typical radiation dose of 40 mGy per scan. They concluded that the increased cancer incidence was mostly due to radiation from CT scans.
BMJ and Lancet Studies
Three landmark papers from Lancet and BMJ published in the past year have confirmed that the theoretical increased risk of cancer does bear out in follow-up studies. Pearce and colleagues' study in Lancet looked at the excess risk of leukaemia and brain tumours for children and adolescents exposed to CTs. They found that children exposed to cumulative doses of 50 mGy (3–5 CTs) may have triple the risk of leukaemia, and doses of 60 mGy may have almost triple the risk of brain tumours. Though this appears to be a very large increase in risk, the authors point out that these cancers are still relatively rare, causing an estimated one excess case of leukaemia and one excess brain tumour per 10 000 head CTs. Moreover, although not specific to the discussion of paediatric patients, the lifetime cancer risk of developing cancer in the general population of 1 in 3 needs to be considered. Nonetheless, the importance of this effect is emphasised by the fact that 12 other groups from 15 countries are studying the risk of scans on children.
The Pijpe et al GEN-RAD-RISK paper published recently in BMJ. This study showed that when women who carry a specific mutation associated with breast cancer (BRCA1/2), and who were exposed to diagnostic radiation before the age of 30, had almost twice the risk of breast cancer (with a dose–response pattern). This study involved lower doses which we had previously considered to be fairly 'safe' (eg, 4 mGy from a single mammogram or shoulder x-ray). Therefore, BRCA1/2 carriers, with an already increased risk of a very common cancer, would be particularly at risk from exposure from radiating scans at a young age.
Most recently, the Matthews et al Australian data linkage study, with an enormous cohort (11 million) showed that the adjusted overall cancer incidence for young people exposed to a CT scan was 24% greater than for those who were not exposed. That is, one in every 1800 scans resulted in an excess cancer case. The relative risk was higher for many different types of cancers and exhibited a dose-response relationship. This is particularly striking as the mean follow up time was 9.5 years, suggesting the true lifetime risk may be much higher. The researchers assumed a typical radiation dose of 40 mGy per scan. They concluded that the increased cancer incidence was mostly due to radiation from CT scans.
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