Chemical exposure before mid-30s may be critical in breast cancer development

March 31, 2010

Occupational exposure to certain chemicals and pollutants before a woman reaches her mid-30s could treble her risk of developing cancer after the menopause, suggests research published in Occupational and Environmental Medicine .

Women exposed to synthetic fibres and petroleum products during the course of their work seem to be most at risk, the research suggests.

The researchers base their findings on more than 1100 women, 556 of whom were diagnosed with breast cancer in 1996/7 in Montreal, Canada, when aged between 50 and 75 and who had gone through the menopause.

The other 613 women, who were matched for age and date of diagnosis, had a range of other cancers, and were intended to act as a comparison group.

An expert team of chemists and industrial hygienists then set about investigating the women's levels of exposure to around 300 different substances throughout the course of their employment history.

After taking account of the usual factors associated with an increased risk of breast cancer, the analysis indicated a link between occupational exposure to several of these substances.

Compared with the comparison group, this risk peaked for exposures before the age of 36, and was magnified with each additional decade of exposure before this age.

This resulted in women occupationally exposed to acrylic fibres running a seven-fold risk of breast cancer, while those exposed to nylon fibres almost doubled their risk.

When tumours were divided into their hormonal responsiveness, women whose cancers responded to oestrogen, but not progesterone, were at least twice as likely to have breast cancer for every 10 year period they were exposed to monaromatic hydrocarbons (a byproduct of crude oil) and acrylic and rayon fibres.

Exposure to polycyclic aromatic hydrocarbons, found in petroleum products, before the age of 36, tripled the risk for women whose tumours were responsive to both oestrogen and progesterone.

The authors concede that their findings could be due to chance alone, but say they are consistent with the theory that breast tissue is more sensitive to harmful chemicals if the exposure occurs when breast cells are still active - in other words, before a woman reaches her 40s. And they point to the rising incidence of breast cancer in developed countries, which is likely to be due to a range of factors, including diagnosis of small slow growing tumours and changes in alcohol consumption.

But environmental and workplace factors are also thought to have a role, they suggest, with previously published evidence implicating exposure to certain chemicals, low frequency electromagnetic fields, and disruption of the body clock.
-end-


BMJ

Related Breast Cancer Articles from Brightsurf:

Oncotarget: IGF2 expression in breast cancer tumors and in breast cancer cells
The Oncotarget authors propose that methylation of DVDMR represents a novel epigenetic biomarker that determines the levels of IGF2 protein expression in breast cancer.

Breast cancer: AI predicts which pre-malignant breast lesions will progress to advanced cancer
New research at Case Western Reserve University in Cleveland, Ohio, could help better determine which patients diagnosed with the pre-malignant breast cancer commonly as stage 0 are likely to progress to invasive breast cancer and therefore might benefit from additional therapy over and above surgery alone.

Partial breast irradiation effective treatment option for low-risk breast cancer
Partial breast irradiation produces similar long-term survival rates and risk for recurrence compared with whole breast irradiation for many women with low-risk, early stage breast cancer, according to new clinical data from a national clinical trial involving researchers from The Ohio State University Comprehensive Cancer Center - Arthur G.

Breast screening linked to 60 per cent lower risk of breast cancer death in first 10 years
Women who take part in breast screening have a significantly greater benefit from treatments than those who are not screened, according to a study of more than 50,000 women.

More clues revealed in link between normal breast changes and invasive breast cancer
A research team, led by investigators from Georgetown Lombardi Comprehensive Cancer Center, details how a natural and dramatic process -- changes in mammary glands to accommodate breastfeeding -- uses a molecular process believed to contribute to survival of pre-malignant breast cells.

Breast tissue tumor suppressor PTEN: A potential Achilles heel for breast cancer cells
A highly collaborative team of researchers at the Medical University of South Carolina and Ohio State University report in Nature Communications that they have identified a novel pathway for connective tissue PTEN in breast cancer cell response to radiotherapy.

Computers equal radiologists in assessing breast density and associated breast cancer risk
Automated breast-density evaluation was just as accurate in predicting women's risk of breast cancer, found and not found by mammography, as subjective evaluation done by radiologists, in a study led by researchers at UC San Francisco and Mayo Clinic.

Blood test can effectively rule out breast cancer, regardless of breast density
A new study published in PLOS ONE demonstrates that Videssa® Breast, a multi-protein biomarker blood test for breast cancer, is unaffected by breast density and can reliably rule out breast cancer in women with both dense and non-dense breast tissue.

Study shows influence of surgeons on likelihood of removal of healthy breast after breast cancer dia
Attending surgeons can have a strong influence on whether a patient undergoes contralateral prophylactic mastectomy after a diagnosis of breast cancer, according to a study published by JAMA Surgery.

Young breast cancer patients undergoing breast conserving surgery see improved prognosis
A new analysis indicates that breast cancer prognoses have improved over time in young women treated with breast conserving surgery.

Read More: Breast Cancer News and Breast Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.