Cancer is among the leading causes of death and morbidity worldwide. Although it is a disease that predominantly affects older people, cancer incidence is increasing among adolescents and young adults. In the UK, cancer outcomes have been historically lagging behind other comparable countries and wide geographical and socio-economic inequalities have been observed within the country. The aim of this PhD is 1) to explore the increasing incidence of cancer among young adults and 2) to describe socio-economic inequalities in cancer outcomes in England. The second aim also entails the estimation of the societal and economic impact of those inequalities and identifying what may be some of the contributing health-system components. The main data source for most analyses was the National Cancer Registration Dataset, enriched with information from Hospital Episode Statistics (HES) in some publications. Socio-economic deprivation of cancer patients was determined by the ecological English Index of Multiple Deprivation (IMD). A wide range of advanced statistical methods was used, including non parametric approaches in the estimation of cancer survival and of alternative measures of cancer survival, the pseudo-observation approach in the estimation of crude probabilities of death due to cancer, hierarchical modelling and penalised regression. For the first aim, I describe trends of colorectal cancer incidence rates in England, focusing on differences by anatomical sub-site and socio-demographic characteristics, particularly age (Research Paper 1). The findings pointed to a steep increase in colorectal cancer incidence among young adults aged 20-39 years in contrast to an overall stabilising trend in older adults. The reasons for these trends remain largely unknown, with most mechanisms pointing to a combination of genetic and lifestyle factors. For the second aim, I set out to assess the effectiveness of the 2000 NHS Cancer Plan and of subsequent strategies in reducing the difference in cancer survival between the most and the least deprived cancer patients in England (Research Paper 2). Despite an overall improvement in cancer survival over time, survival in the most deprived remained consistently lower than in the least deprived. I estimated the impact of these socio-economic inequalities on the Number of Life-Years Lost (NLYL) due to cancer (Research Paper 3). For the vast majority of cancers, the most deprived patients lost more life-time than the least deprived and the largest differences were seen mostly in young adults with poor prognosis cancers. Finally, I explored the role of health care system factors on socio economic inequalities in prompt diagnosis and receipt of treatment. More deprived colon cancer patients used the emergency services more often, presenting with non-specific symptoms or conditions (Research Paper 4). Further, there was wide variation in resection rates and survival from pancreatic cancer between the 23 specialist centres in England where all pancreatic cancer resections are centralised (Research Paper 5). Resection rates for pancreatic cancer remained low at national level. In summary, socio-economic inequalities in cancer outcomes have been persistent in England, costing in lives and resources. My PhD dissertation highlights that delays in diagnosis among more deprived cancer patients may be related to health-system barriers in accessing primary and secondary care. Substantial geographical variation in the resection rates for pancreatic cancer points to further barriers in access to treatment, potentially related to distance and travel time. Future cancer policies and interventions should prioritise inequalities and focus on building a health care system that remove barriers in access for all under-served populations.