Cervical smear test sterilisation process is safe, no evidence for cancerous claims

Using ethylene oxide in the sterilisation process for cervical cancer screening utensils is safe.

(Reuters) - There is no evidence that tools used for cervical cancer screenings are cancerous, despite a video circulating online warning about the sterilisation process of test utensils. A controlled amount of the gas ethylene oxide (EO), a carcinogen, is used to sterilise medical instruments, but the process is safe, experts told Reuters.

In the clip circulating online, a woman phones a person who says they work at a medical supplier and that cervical cancer screening utensils are sterilised with EO. The woman filming the video goes on to suggest cervical smear tests cause cancer as a result (here).

She says: “They’re actually sterilising it with a cancer-causing chemical… and they’re putting that in women … it’s just not on.”

Ethylene oxide can be carcinogenic with certain levels and types of exposure, such as if it is inhaled (here and here).

There is no evidence, however, that its use in cervical screening sterilisation processes is cancerous.

A spokesperson for the Medicines and Health products Regulatory Agency (MHRA), which monitors the safety of medical devices, told Reuters: “There is no credible evidence that the swabs used in cervical smear tests are associated with cancer.

“Ethylene oxide (EO) is a gas that is commonly used to sterilise many different types of medical devices, including swabs and speculae. 

“This is a highly controlled and safe method of sterilisation.”

EO in its gas form is commonly used to sterilise many medical devices (here and here).

Guidance from the World Health Organization (WHO) shows EO is used in the sterilisation process for speculums in line with international standards (here).

It is also used to sterilise swabs for smear tests (here).

Dr Alexander Edwards, Associate Professor in Biomedical Technology at University of Reading, told Reuters that ethylene oxide is used because it can fully sterilise medical products including swabs without affecting the device.

He explains: “Everyone is familiar with the difference between cleaning something and consuming something.

“Before any medical device is released from manufacture, it will be carefully checked to ensure no residual ethylene oxide is left.

“Because ethylene oxide is a gas, it wouldn’t stay around in something like a swab anyway, because it would diffuse away.”

Reuters previously addressed claims around EO’s use in the sterilisation process of Covid-19 test swabs here, here and here .

In response to a Freedom of Information (FOI) request on the use of EO to sterilise swabs for Covid-19 tests, the MHRA said the amount of residual EO allowed was set by the “international standard ISO 10993-7:2008”, based on a person’s contact time with the substance. The limits were selected to pose minimal risk to users (here).

VERDICT

False. The use of ethylene oxide in the sterilisation process for cervical cancer screening utensils is safe and strictly regulated. There is no evidence the tests cause cancer.