Last year, an estimated two million women around the world developed breast cancer or cancer of the cervix (the neck of the womb); more than 600,000 died – the equivalent of six large passenger planes crashing every single day.
The study is the first global analysis of trends in cervical and breast cancer incidence and mortality, using data from 187 countries. It shows that while breast cancer deaths are concentrated among older women in richer countries, 76 percent of cases of cervical cancer now occur in developing countries, where the incidence of the disease is still increasing. Almost half those cases are in women under 50.
The authors conclude: “Our findings show that in developing countries in the reproductive age groups, breast and cervical cancer are substantial problems of a similar importance to major global priorities such as maternal mortality.”
The variations in trends for breast and cervical cancer in countries even within the same region mean “known, major risk factors such as obesity and consumption of animal fat do not account for all recorded patterns. The interaction between genes and the known individual risk factors might explain these divergent trends.”
The study emphasizes the need for better surveillance and data gathering systems.
While figures are abundantly available from Western Europe and North America, as well as India, whole swathes of Africa, especially central Africa, provide hardly any data at all. And even in those African countries that do attempt to keep records, accuracy is still patchy.
One gynaecologist of 40 years’ experience in Lagos, Tayo Sawyerr, told IRIN he felt the city’s statistics were reasonably complete because: “They won’t let you bury a body unless you can produce a death certificate. And the death certificates are identical to those in the UK, and have to show the cause of death.”
Meanwhile, in rural Togo, burial is a private matter, inside the family compound. Registering a death costs money, and with no obvious benefit to the family, many are never recorded.
Even where there is data, the researchers found some countries, such as Uganda, recorded the incidence of cancer, but not the mortality rate. In Tanzania, it was the other way round. Some places simply recorded “cancer” without specifying what kind, or did not distinguish between cervical cancer and cancer of other parts of the womb.
Asked how much confidence he had in the statistics, Raphael Lozano, professor of global health at Seattle’s Institute for Health Metrics and Evaluation, told IRIN: “We were fortunately able to gather information from countries with cancer registries, such as Malawi, Uganda, Namibia, Zimbabwe and South Africa. Both Cape Verde and South Africa had vital registration data [births and deaths]. And we relied on verbal autopsy information from nationally representative studies in Mozambique and Burkina Faso… Our models allowed us to borrow strength from data from countries within the same region and others.
“The quality of the data varies across countries and years, and we correct for this known bias. However, in the case of vital registration, there is good evidence that the quality of reporting of breast cancer on death certificates is acceptable compared to other causes of death.”
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He said he was also confident that the apparent rise in cancers among younger women was not just the result of better maternity services, which meant women were seen regularly by health professionals.
“I believe the rise in cancer in women of reproductive age is real. In some countries the increase is modest, but in others it is quite significant. For example, in Cameroon in 1980, 33 percent of breast cancer deaths were in women [younger than] 50 and in 2010, that fraction increased to 43 percent.
“In Equatorial Guinea the increase was even bigger, from 22 to 43 percent. This can’t all be explained with better screening and better surveillance, especially given the health system challenges in some of these countries.”
Sawyerr is also convinced that the rise, especially in cervical cancer, is real. “I have had a long career,” he says, “and I am unfortunately surprised that I am beginning to see a lot of people with cervical dysplasia [abnormal cell growth in the cervix] and with HPV involvement. I am treating one woman at the moment for cancer of the cervix and she is just 34 years old.”
HPV is the Human Papilloma Virus, a sexually transmitted disease implicated in the development of cancer of the cervix. A vaccination against HPV is now available and – together with regular screening – is one of the factors reducing the incidence and mortality from cervical cancer in richer countries.
But with the vaccine initially costing about US$300 for a course of three doses it was priced beyond the reach of developing countries. Now the Global Alliance for Vaccines and Immunisation, GAVI, has negotiated a price of $5 a dose with the manufacturers, and is planning to roll out the vaccine in eligible countries soon.
Senegal’s Health Minister, Modou Diagne Fada, told IRIN in June he hoped it would be available there by 2015. “Nowadays malaria is no longer our leading cause of death. Today the leading causes of death are chronic diseases, and non-transmissible diseases, especially cancer. Among these cancers there is one which is very deadly, cervical cancer, and I think the introduction of the vaccine against the Human Papilloma Virus would help us reduce the number of our women who die from this disease.”