Cancer has been linked to radiation from CT scans in a study from a National Health Insurance dataset in Taiwan carried out between 2000 and 2013. The study followed 22,853 thyroid cancer, 13,040 leukaemia, and 20,157 non-Hodgkin lymphoma cases.
Researchers consulted data from the National health Insurance programme to study demographic and medical information on disease diagnoses, procedures, and drug prescriptions, and the enrolment profiles of all patients.
Patients were excluded if they were under 25 years at the time of the cancer diagnosis, had less than three years of follow-up before cancer diagnosis, or had a history of a cancer before the year 2000.
Results showed patients who developed thyroid cancer and leukaemia had significantly higher likelihood of having received CT scans.
In studies that combined patients across age groups, exposure to medical CT scans was not associated with increased risk for non-Hodgkin lymphoma.
Cancer warning: Radiation from CT scans has been linked to an increased risk of the disease (Image: GETTY)
But in patients between 36 and 45 years of age, there was a three-fold increased risk of non-Hodgkin lymphoma associated with CT scans.
In older patients the association between exposure to CT scans and non-Hodgkin lymphoma was not evident.
Researchers concluded patients receiving CT scans had in general marked increases in the risk of developing thyroid cancer and leukaemia, especially in female patients and patients younger than 45.
Yu-Hsuan Joni Shao, one of the paper’s author, said: “Our study found that CT scans are associated with an increased risk of thyroid cancer and leukaemia in adults in all ages and with non-Hodgkin lymphoma in young adults.
“The risk is stronger in patients who have higher cumulative doses from multiple scans.
“The increased numbers of people undergoing CT scans have become a public health issue."
Cancer Research UK recognises radiation as a possible risk for cancer.
It says: “A CT scan is a safe test for most people but like all medical tests it has some possible risks.
“Your doctor and radiographer make sure the benefits of having the test outweigh these risks.”
The cancer charity adds: “Exposure to radiation during a CT scan can slightly increase your risk of developing cancer in the future. Talk to your doctor if this worries you.”
Other possible risks associated with CT scans:
- Allergic reaction
- Bruising and swelling
- Kidney problems
- Pregnancy - pregnant women should only have CT scans in emergencies.
Alongside recognising the causes of cancer and how you could prevent it, recognising the symptoms of cancer is important.
Symptoms of thyroid cancer
The NHS says the symptoms of thyroid cancer can include:
- A painless lump or swelling in the front of the neck – although only 1 in 20 neck lumps are cancer
- Swollen glands in the neck
- Unexplained hoarseness that does not get better after a few weeks
- A sore throat that does not get better
- Difficulty swallowing
Symptoms of leukaemia
Leukaemia symptoms are listed by Leukaemia UK as:
- Unexplained weight loss
- Feeling toreador weak
- Easily bruise or bleed
- Swollen lymph nodes
- Swollen stomach
- Fever/night sweats
- Pain in bones/joints
If you experience any of these symptoms, see your GP.