Asbestos linked to cancer of the ovaries and larynx
Exposure to asbestos, which is known to cause a form of cancer called mesothelioma, has also been shown to cause some cancers of the ovary and larynx (voice box) as well, scientists have said.
Experts have been aware of the link between asbestos and mesothelioma since the 1960s and the substance is known to cause most cases of the disease, which affects the tissue that lines the outer surface of the lungs.
Writing in a review in the Lancet Oncology this month, an international team of World Health Organisation experts claim that there is now "sufficient evidence" that asbestos can also cause cancer of the ovary and the larynx.
Basing their conclusion on a new 'meta-analysis' of previously published studies, the scientists revealed that people who have been exposed to asbestos are 1.4 times more likely to develop cancer of the larynx than those who have never been exposed to the material, while high levels of exposure are associated with a twofold increased risk of the disease.
Women who were heavily exposed to asbestos at work - including those who manufactured gas masks during World War II - consistently had an increased risk of ovarian cancer and research suggests that the substance can accumulate in the ovaries.
The scientists noted that "all types of asbestos are carcinogenic to humans" and say that there is also some evidence to suggest that the substance may increase a person's risk of cancers of the bowel, stomach and throat.
They also warned of the widespread nature of exposure to asbestos, with an estimated 125 million people around the world still thought to be exposed to asbestos in the workplace.
Despite being banned in the UK since 1999, its use is increasing in Asia, South America and the former Soviet Union and it can often be found in common products such as brake linings.
Dr Alison Ross, Cancer Research UK's senior science information officer, said: "We already know asbestos can cause lung cancer and mesothelioma and this adds two more cancer types to the list.
"But it's important to know that the majority of ovarian and laryngeal cancers are not caused by exposure to asbestos.
"And thankfully, because of changes in the law relating to asbestos use in the 1980s, we should see the number of asbestos-related cancers declining in future years."
Mesothelioma can take up to 40 years to develop following exposure to asbestos.
The substance was used extensively in the UK after the second world war because of its insulating properties, so experts predict that the number of cases is likely to rise over the next 20 years before starting to fall.
Straif, K., Benbrahim-Tallaa, L., Baan, R., Grosse, Y., Secretan, B., El Ghissassi, F., Bouvard, V., Guha, N., Freeman, C., & Galichet, L. (2009). A review of human carcinogens”Part C: metals, arsenic, dusts, and fibres The Lancet Oncology, 10 (5), 453-454 DOI: 10.1016/S1470-2045(09)70134-2