In the linked article (doi:10.1136/bmj.c3620), Autier and colleagues report that (population based) breast cancer mortality rates have fallen over the past two decades in many European countries, with a greater decline in the United Kingdom than in any other large country.1 That the UK is leading Europe in the speed with which national breast cancer mortality rates are falling is in stark contrast to, and at first sight difficult to reconcile with, claims that survival after breast cancer onset is worse in the UK than elsewhere in western Europe.2

The unpromising UK cancer survival estimates are, however, misleading. In contrast, population based mortality trends are reasonably reliable (at least in middle age, for example, people aged 35-69 years) because a death certificate is legally required before someone can be buried or cremated. Although the certified cause of death can be wrong, particularly in older people (for example, those over 70 or 80 years), in younger people errors in death certification should have relatively little effect on the assessment of breast cancer mortality trends in western Europe or North America.3

In contrast with death registration, cancer …