Do mammograms (breast X-rays) induce breast cancer in recent research?

From the Guidelines

No, mammograms do not cause cancer according to recent research. Mammograms are a safe and effective screening tool for breast cancer. While mammograms do use low-dose X-rays, the radiation exposure is very small and not considered enough to cause cancer 1. The benefits of early breast cancer detection through regular mammograms far outweigh any potential risks from the minimal radiation exposure.

Key Points

• The radiation exposure from mammograms is very small and not considered enough to cause cancer 1.
• Mammograms have been shown to decrease breast cancer mortality by 22% to 40% in women who are actually screened 1.
• The American College of Radiology recommends annual screening mammography beginning no later than 40 years of age for women at intermediate risk 1.
• Women should continue screening mammography as long as they remain in overall good health and are willing to undergo the examination and subsequent testing or biopsy, if an abnormality is identified 1.
• The safety of mammography is based on decades of research and millions of screenings, with modern digital mammography equipment using even lower radiation doses than older film-based systems, further reducing any theoretical risk 1.

Screening Recommendations

• Annual screening mammography is recommended for women 40 to 84 years of age, with a mortality reduction of 40% (12 lives per 1,000 women screened) 1.
• Biennial screening mammography for women 50 to 74 years of age results in a mortality reduction of 23% (7 lives per 1,000 women screened) 1.
• Women with a family history of breast cancer or other high-risk factors may need to start screening earlier, typically 10 years prior to the youngest age at presentation but generally not before 30 years of age 1.

From the Research

Mammography and Breast Cancer Risk

• The current evidence suggests that the risk of breast cancer induced by mammography is small compared to the potential benefits of screening 2, 3, 4, 5.
• A study published in 2022 found that the average mean glandular dose from a single mammography examination is around 2.5-3 mGy, resulting in 65 induced cancers and 8 deaths per 100,000 women over a screening lifetime from 40-74 years 2.
• Another study published in 1996 calculated the ratio of benefit to risk for women who begin annual mammography screening at different ages, and found that the benefit exceeds the radiation risk by a factor of almost 100 for women starting screening at age 50 and continuing until age 75 3.
• A review published in 2016 estimated that the carcinogenic risk of biennial screening in women aged 50-74 years is about 1.6‰, which is considered small in relation to the potential beneficial effects of screening 5.
• However, it is noted that individuals who are known to be carriers of risk-increasing genetic variations and/or have an inherited disposition of breast cancer should avoid ionizing radiation as much as possible and should be referred to alternative imaging modalities such as ultrasound or magnetic resonance imaging 5.

Radiation Risk and Age

• The risk of radiation-induced breast cancer is thought to be higher for younger women, particularly those under the age of 35 3, 4.
• A study published in 2011 found that by the time women reach their late thirties and early forties, there is no measurable risk from mammographic doses, and even the extrapolated risk is far below even the smallest benefit from screening 4.
• However, the evidence suggests that the benefits of screening outweigh the risks for women aged 40 and older 2, 6, 3, 4.

Screening Guidelines

• The American College of Radiology and the Society of Breast Imaging recommend annual mammography screening beginning at age 40, which provides the greatest mortality reduction, diagnosis at earlier stage, better surgical options, and more effective chemotherapy 6.
• Screening guidelines vary by country, but most recommend annual, biennial, or triennial screening from ages 40-74 years 2.