Focus on cancer: NIH supports cancer research to reduce disease burden

July / August 2018 | Volume 17, Number 4

Full July / August 2018 Global Health Matters newsletter [PDF <1M]

Medical student works with a patient, teacher and other students observe

Photo by Richard Lord for Fogarty

Trainees in Uganda learn to scan patients for breast cancer
with support from Fogarty’s Medical Education Partnership
Initiative.

By Karin Zeitvogel

Cancer is increasingly striking populations in low-resource settings, due to rising longevity and other risk factors. Around 70 percent of the 8.8 million cancer deaths that occurred globally in 2015 were in low- and middle-income countries (LMICs), where most new cancer cases are diagnosed and there are the fewest resources to treat them. The forecast is grim, with the WHO predicting the number of new cases will increase by more than 50 percent by 2030.

Lung cancer is the most common cancer in the world. Of the estimated 1.8 million new cases worldwide in 2012, 58 percent were in less developed regions. Most cases are caused by smoking - and around 80 percent of the world's 1.1 billion smokers live in LMICs, according to the WHO.

Breast cancer is the second most common cancer, according to WHO’s 2012 data, although a more recent report shows that it may have surpassed lung cancer to become the most common globally. Improved screening and care have meant the mortality rate for breast cancer has fallen but those gains have been concentrated in high-income regions. In sub-Saharan Africa, where many women present with late-stage disease, fewer than half survive beyond five years, compared with nearly 90 percent in the U.S.

Caused by the human papilloma virus (HPV), cervical cancer is the most common cancer among women in parts of Africa, Asia and Latin America. It is three times more likely to occur in HIV-infected women, whose immune systems are too weak to fight an HPV infection, than uninfected women. Together with Kaposi’s sarcoma and non-Hodgkin’s lymphoma, cervical cancer is considered an HIV-associated malignancy, which are more prevalent in LMICs where HIV infection continues to be widespread.

Other common cancers in developing countries include prostate, liver, stomach and esophageal cancer.

Researchers note that cancer instances are likely underreported in resource-poor countries, as few have cancer registries. Only around 11 percent of the population in Africa and six percent in Asia are covered by registries. Cancer prevalence in LMICs is expected to continue to grow because of:

Improved treatment and prevention of childhood, infectious and parasitic illnesses, and lower maternal mortality rates, which have allowed people to live into middle- and old-age, when most cancers occur.
Rising rates of obesity caused by changes to diet and reduced levels of physical activity due to urbanization and other causes. Obesity has been associated with more than a dozen cancers including breast - particularly in post-menopausal women - ovarian, esophageal and colorectal.
Gene mutations, environmental factors such as indoor and outdoor pollution, and viral illnesses in addition to HIV, including hepatitis B or C, are also risk factors for cancer.

Cancer deaths rising fastest in LMICs

Bar graph shows cancer deaths in millions per year in 2005, 2015 and 2030, full description follows

Data Source: Globocan

Cancer currently accounts for ~12.5% of global deaths

Description of graph: Bar graph shows cancer deaths in millions per
year, comparing the world total to deaths in LMICs and High-income
countries. By 2030 the estimated world total is approximately 11 million
deaths, with more than 8 million deaths in LMICs, and less than 3 million
deaths in high-income countries.

To stem the tide of cancer in LMICs, scientists say a multi-pronged approach is needed. Fogarty and NIH partners are supporting numerous projects to improve cost-effective and practical diagnostic tools and treatment options, explore genomics research, study tobacco cessation approaches and deploy mobile technology solutions, among others.

Studying cancers that are common in Africa, Asia or Latin America but rare in developed countries has allowed researchers to “reverse innovate” and use their findings to help cancer patients in the developed world - such as by bringing down the cost of treatment and finding less invasive ways to treat cancer.

Researchers are also working to establish and expand cancer registries, which indicate how common certain cancers are, how frequently they occur, how well people are surviving and if there are clusters caused by environmental degradation or infections like HIV - all of which change a person’s risk for cancer and can provide useful directions for future studies.