Exploring sex differences in global cancer incidence and mortality and the role of national development level

Abstract

Background We analysed sex differences in global cancer incidence and mortality using a national development index to better understand how broader socioeconomic factors may contribute to or mitigate sex differences in cancer outcomes. Materials and methods Cancer incidence and mortality data (2012-2017) were obtained from the International Agency for Research on Cancer, covering 43 countries for incidence and 60 for mortality. Only nonsex-specific cancers were included and categorised into 12 groups. Age-standardised incidence rates (ASIR) and age-standardised mortality rates (ASMRs) were calculated, with sex differences analysed using men-to-women ratios (MWRs). Linear regression was used to assess the association between Human Development Index (HDI) and MWRs across cancer types. Results Among the cancer types included in this study, cancers of the colorectum, stomach, and lungs showed the highest incidence and mortality. Men are 12-13 times more likely to be diagnosed with oesophageal cancer (MWR ≈ 13), over nine times more likely to die from head and neck cancers, and >6 times more likely to die from lung cancer. Thyroid cancer incidence is up to five times higher in women than in men. No clear link was found between HDI and MWRs in incidence, but HDI relates to mortality and MWRs for several cancer types, with brain and thyroid cancers showing higher male mortality, while lung cancer showing relatively higher female mortality in high-HDI countries. Conclusions Sex differences in cancer burden vary substantially across cancer types. National development was associated with sex differences in mortality, but not incidence, suggesting that factors related to health care and survival differ more between countries with different HDIs and contribute to these differences more than exposure to risk factors, which relates more to incidence.