Cancer is a leading cause of death worldwide among women in both high-income countries and middle-income countries. Among females, cancer is the second leading cause of death worldwide, accounting for 14% of all deaths (Table 2.1). According to estimates from the World Health Organization (WHO) International Agency for Research on Cancer (IARC), there were 6.7 million new cancer cases and 3.5 million deaths among females worldwide in 2012 (Ferlay, Soerjomataram et al. 2015). Of these, 56% of cases and 64% of deaths were in less developed countries. These numbers are expected to increase to 9.9 million cases and 5.5 million deaths among females annually by 2030 as a result of the growth and aging of the population (Ferlay, Soerjomataram et al. 2015).