Gynaecological cancers more common in urban areas

Gynaecological cancers are far more likely to happen in women living in urban areas than in rural areas, according to a study published in BJOG: An International Journal of Obstetrics and Gynaecology.

US and Egyptian researchers analysed data from Egypt and found the incidence of gynaecological cancers including uterine, ovarian and cervical cancer was collectively almost four times higher on average in urban women than in their rural equivalents.

The study suggests women in urban areas may have a higher exposure to environmental xenoestrogens (industrially made compounds that have an oestrogenic activity), which may increase the risk of developing hormone-related cancers.

Numerous existing studies have shown that environmental xenoestrogen presence and exposure is higher in urban areas. Previous research has shown a three to four times higher urban incidence of breast cancer and estrogen receptor positive breast cancer.

In this study, the researchers investigated the urban-rural incidences of gynaecological cancers to see if they demonstrated the same trend.

They analysed data from the Gharbiah Cancer Registry for the four-year period of 1999-2002. The study population consisted of all women diagnosed with uterine, ovarian and cervical cancer in the Gharbiah Province of Egypt during this time.

They found the incidence of all three cancers (uterine, ovarian and cervical cancer) was higher in urban areas and there was an almost six times higher incidence of uterine cancer among urban women.

There was also a gradient of increasing urban-rural differences for all female cancers.

Cancers such as leukaemia (which are mainly genetically determined) had the lowest urban-rural difference, followed by that seen for all non-hormonally related cancers.

When they included cancers that are largely hormonally dependent, this increased the urban-rural difference by almost 70% (the urban-rural difference increased by 146% when only hormonal cancers were considered).

Lead author Dr Amr Soliman, associate professor of epidemiology at the University of Michigan School of Public Health, US, said: “In this population, there is no significant urban-rural difference among women with respect to other risk factors for uterine and breast cancer, healthcare access, and behaviour.

“There is also very low use of hormonal pills or therapy among Egyptian women. The higher exposure of urban women to man-made chemicals in the environment that act as hormones is the probable risk factor.”

Professor Philip Steer, BJOG editor-in-chief, said: “This study adds to a growing body of literature demonstrating the impact of environmental chemicals on human health.

“The findings suggest that urban women have a much higher exposure to hormonal agents that increase the risk of them developing hormone-dependent cancers.”