The Burden of Cancer in Developing Countries

suggest that five-year relative survival rates of ovarian cancer are surprisingly similar in developed (from 31 to 42 percent) and developing countries (16 to 51 percent).16 Ovarian malignancies can occur at all ages, but the risk is generally higher near age 40. Women with ovarian cancer often present with non-specific symptoms including abdominal bloating, urinary urgency, and difficulty eating. Diagnosis of ovarian cancer is particularly challenging because of the vague presenting symptomatology. Consequently, particularly in developing countries, the majority of patients present with advanced disease103;104 and are diagnosed late—this results in a high fatality rate compared to other reproductive health cancers.5 Research studies in the U.S. have shown that the greatest risk factor for ovarian cancer is family history and genetic syndromes associated with ovarian cancer.105 Carriers of the BRCA1 or BRCA2 gene mutations are at increased risk for ovarian cancer;106 genetic testing may provide a method of screening high risk patients for ovarian cancer in order to make way for heightened surveillance in these patients. Other risk factors for ovarian cancer include low parity, delayed childbearing, early menarche, endometriosis, and high fat diet.107 Low parity has been identified as a risk factor for ovarian cancer in women in industrialized countries. The risk for developing ovarian cancer is reduced with oral contraceptive use and pregnancy of any duration.108 Current evidence suggests that oral contraceptives have prevented about 200,000 ovarian cancers and 100,000 deaths from the disease globally, and that over the next few decades the number of cancers prevented will rise to at least 30,000 per year.37;109 Tubal ligation was also noted to significantly reduce the risk of ovarian cancer, even after considering confounders like maternal age at first birth and frequency of childbearing.110 Increased consumption of fruits, vegetables and green tea has been associated with reduced risk of ovarian cancer, even after adjusting for mean food intake, BMI, and energy expenditure, age, smoking and alcohol consumption. Intake of animal fat conferred the greatest correlation with ovarian cancer.111;112 Cancer antigen 125 (CA 125), a serum marker for ovarian cancer, is often used to screen women for ovarian cancer. The United States Preventative Task force however recommends against routine screening in asymptomatic patients.105 In South Africa, CA 125 has been shown to be valuable in follow up management and early detection of recurrent disease.113 However, in most developing countries, CA 125 is not readily available or is likely unaffordable. In developed countries, survival rates have improved in the recent decades, mainly due to progress in treatment, including the development of refined surgical procedures and effective chemotherapy regimens.114;115 Optimal chemotherapy regimens in resource poor settings are yet to be determined. Current chemotherapy protocols are based on the experience of developed countries and may not necessarily be successful in developing country settings.116;117 Collaboration between developed and developing nations is key to bridging the gap to care and treatment of ovarian cancer.

Endometrial cancer. Endometrial cancer or uterine corpus cancer is the third most common cancer in women and accounts for 6 percent of all cancers in women.118 In 2000, 189,000 new cases of endometrial cancer occurred in women globally.5 However, rates vary worldwide and are highest in North America and Northern Europe; intermediate in Latin America, Southern Europe and Israel; 14 / The Burden of Cancer in the developing countries: A Global Health Council Report on the Cancer Advocacy and Learning Institute, June, 2010