Standard protective equipment does not fully protect breast tissue from radiation and regularly exposed female healthcare workers need better protection to help minimise their risk of developing breast cancer, according to an editorial in the BMJ.
Lead author Isobel Pilkington, a core surgical trainee in Wessex Deanery, and colleagues, pointed out that ionising radiation is a known human carcinogen, and breast tissue is highly radiation sensitive. According to Cancer Research UK, around 1% of breast cancer cases in the UK are caused by radiation exposure.
There is a linear relationship between increasing exposure and increasing risk and exposure to ionising radiation during image-guided procedures has been associated with a higher incidence of breast cancer in female healthcare workers.
However, quantifying the risk of occupational radiation-induced breast cancer in women working in healthcare is "challenging", the editorial explained, because longitudinal data have not been widely collected. Such data acquisition is complicated by the interval between exposure and development of disease, and the relatively small number of women working in image guided specialties.
As an example, however, studies of female US orthopaedic surgeons have reported a 2.9- to 3.9-fold increase in the prevalence of breast cancer, compared with an age-matched female population, whereas female plastic and urological surgeons with similar lifestyles and pregnancy histories did not share this augmented risk. Increased rates of breast cancer have also been found in cohorts of radiological technicians.
Current PPE Provides 'Inadequate Protection'
Although personal protective equipment (PPE) such as lead or lead-equivalent gowns are used to shield the body from radiation exposure during imaging procedures, studies have shown that current radiation PPE provides inadequate protection to breast tissue because it leaves exposed the most common sites of breast cancer - the upper outer quadrant and axilla.
Tests using an artificial female torso wearing commonly used PPE with simulated intraoperative positioning have shown a large variance in radiation exposure, inadequate protection of the upper outer quadrant, and no significant reduction in dose when a standard protective gown was compared with a torso without protection.
In another study of the standard protective gown worn by orthopaedic surgeons, dosimeter readings showed that the area adjacent to the axilla received the highest upper body radiation dose.
There has also been "historical underestimation of the impact of ionising radiation on breast tissue," the authors noted, such that in 2007 the International Commission on Radiation Protection revised its guidelines to double the relative detriment of ionising radiation for breast cancer. However, in contrast to other radiation sensitive areas such as the eyes and thyroid, "no occupational dose limits exist for breast tissue". They called for "clear guidelines on an acceptable dose of ionising radiation to the female breast" to facilitate improvements in governance of radiation exposure in the workplace.
The Ionising Radiation Regulations 2017 state that the radiation dose delivered to workers should be as low as reasonably achievable (the ALARA principle). Ways to achieve this include reducing the duration of exposure, increasing the distance from the source, and shielding all workers with effective protective clothing.
Axillary Shielding Could Reduce Exposure by 99%
Current standard gowns cover the torso, reproductive organs, and femurs, with additional thyroid protection available. It would be possible to design gowns specifically to protect the upper outer quadrant of the breast, for example with axillary shields, sleeves that can be worn under standard gowns, gowns with capped sleeves, or axillary wings. The addition of such axillary coverage or sleeves has been found to decrease intraoperative irradiation to the upper outer quadrant by 99%.
"Ionising radiation is a mitigatable risk factor, and exposure should be kept as low as reasonably practicable," the authors said. "Steps must be taken to ensure full protection of breast tissue." Women working in healthcare who are regularly exposed to radiation from x-rays and other imaging procedures need better protection from ionising radiation and the consequent risk of breast cancer.
"Providing protective gowns with adequate breast covering could reduce radiation exposure and potentially help prevent breast cancer in female healthcare workers."
The authors noted that women make up 7%, 12%, and 16% of the UK trauma and orthopaedic, interventional radiology, and cardiology consultant workforces, respectively. "As the number of female trainees entering these specialties increases, it is essential that the risks are further investigated, available evidence is considered, and equipment provision improved to minimise this risk," they said.
The authors declared no conflicts of interests.