Menopausal hormone therapy and risk of oesophageal adenocarcinoma in a population-based cohort study

Background The Swedish National Inpatient Register (IPR), also called the Hospital Discharge Register, is a principal source of data for numerous research projects. The IPR is part of the National Patient Register. The Swedish IPR was launched in 1964 (psychiatric diagnoses from 1973) but complete coverage did not begin until 1987. Currently, more than 99% of all somatic (including surgery) and psychiatric hospital discharges are registered in the IPR. A previous validation of the IPR by the National Board of Health and Welfare showed that 85-95% of all diagnoses in the IPR are valid. The current paper describes the history, structure, coverage and quality of the Swedish IPR. Methods and results In January 2010, we searched the medical databases, Medline and HighWire, using the search algorithm "validat* (inpatient or hospital discharge) Sweden". We also contacted 218 members of the Swedish Society of Epidemiology and an additional 201 medical researchers to identify papers that had validated the IPR. In total, 132 papers were reviewed. The positive predictive value (PPV) was found to differ between diagnoses in the IPR, but is generally 85-95%. Conclusions In conclusion, the validity of the Swedish IPR is high for many but not all diagnoses. The long follow-up makes the register particularly suitable for large-scale population-based research, but for certain research areas the use of other health registers, such as the Swedish Cancer Register, may be more suitable.

Oesophageal cancer is a clinically challenging disease that requires a multidisciplinary approach. Extensive treatment might be associated with a considerable decline in health-related quality of life and yet still a poor prognosis. In recent decades, prognosis has gradually improved in many countries. Endoscopic procedures have increasingly been used in the treatment of premalignant and early oesophageal tumours. Neoadjuvant therapy with chemotherapy or chemoradiotherapy has supplemented surgery as standard treatment of locally advanced oesophageal cancer. Surgery has become more standardised and centralised. Several therapeutic alternatives are available for palliative treatment. This Seminar aims to provide insights into the current clinical management, ongoing controversies, and future needs in oesophageal cancer.

The two major histological types of oesophageal cancer--adenocarcinoma (AC) and squamous cell carcinoma (SCC)--are known to differ greatly in terms of risk factors and epidemiology. To date, global incidence estimates for individual subtypes are still lacking. This study for the first time quantified the global burden of oesophageal cancer by histological subtype. Where available, data from Cancer Incidence in Five Continents Vol. X (CI5X) were used to compute, age-specific, sex-specific and country-specific proportions of AC and SCC. Nine regional averages were computed for countries without CI5X data. The proportions were then applied to all oesophageal cancer cases from GLOBOCAN 2012 and age-standardised incidence rates calculated for both histological types. Worldwide, an estimated 398,000 SCCs and 52,000 ACs of the oesophagus occurred in 2012, translating to incidence rates of 5.2 and 0.7 per 100,000, respectively. Although SCCs were most common in South-Eastern and Central Asia (79% of the total global SCC cases), the highest burden of AC was found in Northern and Western Europe, Northern America and Oceania (46% of the total global AC cases). Men had substantially higher incidence than women, especially in the case of AC (male to female ratio AC: 4.4; SCC: 2.7). These first global estimates of oesophageal cancer incidence by histology suggested a high concentration of AC in high-income countries with men being at much greater risk. This quantification of incidence will aid health policy makers to plan appropriate cancer control measures in the future. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.