Can radiation from medical scans increase the risk for breast cancer?

Medical imaging, including mammography, X-rays, and CT scans, plays a vital role in the detection, diagnosis, and monitoring of various health conditions, including breast cancer. However, concerns are often raised regarding whether repeated exposure to radiation from these tests may increase an individual’s risk of developing breast cancer.
Imaging techniques such as X-rays and CT scans involve ionising radiation, which has the potential to damage DNA. In rare instances, such damage can lead to cancer. However, the doses used in most diagnostic imaging are very low, and the associated cancer risk is considered minimal.

A recent review published in the European Journal of Radiology reported that a standard mammogram delivers approximately 1–10 milligray (mGy) per breast, depending on factors like breast size and tissue density. This level of exposure is classified as low-dose and is deemed safe in clinical practice. Even higher-radiation tests, such as CT scans, are unlikely to significantly increase cancer risk when used judiciously.

Breast cancer risk: Who should be cautious?
For the majority of adult women, the likelihood of developing breast cancer as a result of medical imaging is extremely low. Mammography remains one of the most effective tools for early detection and significantly improves survival outcomes.

However, women with a strong family history of breast cancer, BRCA1/2 mutations, or those requiring frequent imaging from a young age may benefit from individualized assessment. In such cases, adjunct modalities such as MRI or ultrasound, which do not involve ionising radiation, are considered to space out the mammograms.

Tips for minimising the risk:Maintain a record of prior imaging studies and share this with healthcare providers.
Discuss the necessity of each scan and explore whether lower-radiation or non-radiation options are appropriate.
Adhere to evidence-based screening guidelines, such as biennial mammograms beginning between ages 40 and 45, unless otherwise advised.
While ionising radiation from diagnostic imaging carries a theoretical cancer risk, current evidence indicates that this risk is very small, particularly when imaging is medically indicated and performed at appropriate intervals. The clinical benefits of early cancer detection and accurate diagnosis far outweigh the minimal potential harm from radiation exposure.
Patients are encouraged to have open discussions with their healthcare providers to ensure that decisions around imaging are informed, necessary, and tailored to their individual health profiles.

Dr. Karishma Kirti, Consultant Breast Specialist and Oncoplastic Surgeon