Recent trends in incidence of and mortality from breast, ovarian and endometrial cancers in England and Wales and their relation to changing fertility and oral contraceptive use

Abstract

Summary Reproductive-related factors play a major role in the aetiology of cancers of the breast, ovary and endometrium. Pregnancy history influences the risk of each of these cancers, and oral contraceptive use modifies the risks of ovarian and endometrial cancers, although its effect on breast cancer risk is less certain. We analysed recent time trends in the incidence and mortality of these cancers in England and Wales and assessed whether they can be explained by changes in fertility and oral contraceptive use. During 1962-87, there were significant increases in the overall incidence of breast cancer (0.95% increase per annum) and ovarian cancer (0.76% per annum) but little increase in endometrial cancer (0.13% per annum). At young ages incidence of each of the cancers has declined in recent years, whereas at older ages there have been substantial increases. Mortality data show similar time trends. In analyses by birth cohort, incidence of each of the cancers increased steeply for successive cohorts born before the turn of the century, and more slowly for cohorts thereafter, reaching a maximum for those born in the 1920s, and decreased for those born subsequently. The increases in incidence for women born before the turn of the century paralleled marked declines in their fertility. The fall in risk for women born after the 1920s was not accompanied by significant increases in their fertility, but coincided with the introduction and increase in use of oral contraceptives. For ovarian and endometrial cancers this accords with strong evidence from person-based studies of the protective effect of oral contraceptives. For breast cancer, the reasons for the recent decline are not clear. It would accord with recent suggestions of a long-term protective effect of oral contraceptives, on which further studies are needed. It is also possible, however, that changes in other risk factors such as dietary fat intake and menarcheal age might have contributed to the recent declines in the risk of these cancers.

Geographic and temporal variations in cancer of the corpus uteri: Incidence and mortality in pre- and postmenopausal women in Europe

“…Incidence has been reported to have increased for several decades up to the early 1980s, [12][13][14] while subsequently some declines have been reported in East Germany, 17 Sweden, 15 Switzerland 18 and England and Wales. 16,19 The results presented here are in accordance with these previous reports and update and expand the analysis to countries where trends have not been reported. Further, the systematic approach utilised in this study, allowing a Europe-wide description of the contrasting variations in secular incidence and mortality trends, is a useful tool to better understand the causes of corpus uteri cancer and how best to develop effective population-specific prevention strategies.…”

“…37 Combined oral contraceptives became increasingly available after their introduction in the 1960s, and their use has become widespread among women of reproductive age, particularly in higher-resource countries, where long-term use is common. 38 Previous studies examining incidence trends in Europe have noted a decline in young women, [15][16][17][18][19] several attributing the observations to oral contraceptive use.…”

“…Instead, incidence trends in many European populations increased for several decades up to the early 1980s, [12][13][14] with subsequent declines in several countries. [15][16][17][18][19] Widespread use of combined oestrogen-progesterone HRT from the 1970s onwards together with the widespread use of combined oestrogen-progestin contraceptives introduced during the 1960s, which markedly reduce a woman's corpus uteri cancer risk, have been suggested as important factors responsible for the favourable trends. Mortality rates have generally been decreasing with time in most European populations.…”

Endometrial Cancer Incidence Trends in Europe: Underlying Determinants and Prospects for Prevention

“…Nulliparity decreased in most European countries for cohorts born from 1930 to 1945 (32). In England and Wales, where data are available for a longer period, the decline in nulliparity began for cohorts born since 1910 (15). A recent study indicated that reproductive patterns may account for about half of the cases of endometrial cancer in Sweden in women diagnosed from 1961 to 2002 (33), although the importance of reproductive behavior on risk has been shown to decrease at older ages (34).…”

“…More recent studies in Sweden (11), East Germany (12), Switzerland (13), and the United Kingdom (14-16) have indicated steady declines in endometrial cancer incidence rates among younger women and in more recent birth cohorts. Most have attributed this phenomenon to the increasing prevalence of COC use (11)(12)(13)(14)(15).…”