An Epidemiologic Study of the Relationship of Reproductive Experience to Cancer of the Ovary1

Abstract

epidemiologic study of the relationship of reproductive experience to cancer of the ovary. Am J Epidemiol 99: 190-209. 1974.-From June 1957 to September 1965, all patients entering the Roswell Park Memorial Institute in Buffalo, New York, completed a questionnaire providing detailed information on demographic and social attributes, family history, radiation exposure, menstrual and reproductive characteristics and personal habits. Over 400 cases of ovarian cancer were admitted. These, combined with control groups consisting of patients with other cancers (colo-rectum and breast) and with non-neoplastic diseases, formed the basis of the current study. The findings in this study showed that women with ovarian cancer had the following characteristics: 1) a lower mean number of pregnancies, even when pregnancy rates were calculated per 1000 person-years at risk of the event; 2) a larger proportion of never-pregnant and ever-pregnant women with one or two conceptions; 3) an increase in the relative risk of cancer of the ovary as the total number of pregnancies decreases; 4) a greater risk of ovarian cancer in ever marriednever pregnant than in never-married women; 5) a late age at first pregnancy, except in the comparison with breast cancer controls; 6) a greater interval between first marriage and first conception; 7) a greater difference with their mothers in completed sibship size; 8) a larger proportion of women who tried and failed to become pregnant at least once; and 9) an increase in the frequency of conceptions terminating as miscarriages. Several explanations for these findings were considered. It was generally felt that the results indicated that women who developed ovarian cancer had a gonadal status that predisposed to both the ovarian cancer and the low fertility. cancer of ovaries; fertility, low; ovarian neoplasms; reproductionThere have been very few epidemiologic and cancer registries. There are only three studies of cancer of the ovary except for the published reports dealing specifically with analyses of data obtained from mortality ovarian neoplasms; all have been pubrecords, ad hoc cancer morbidity surveys lished since 1966.

Risk factors for ovarian cancer: a case-control study

“…A lower frequency of hysterectomy, of unilateral oophorectomy, or of both among cases compared to controls has also been reported from several other studies (Wynder et al, 1969;Joly et al, 1974;Annegers et al, 1979;McGowan et al, 1979;Franceschi et al, 1982;Cramer et al, 1983). As these studies were case-control in design, there may have been some misclassification of controls who, rather than having a hysterectomy with ovarian conservation, actually had a hysterectomy with bilateral oophorectomy.…”

“…The raised risk for women with a first pregnancy after 35 years persisted (RR = 3.9, 95% CI 1.1-14.2). Results from other studies regarding the risk for women having a first child at relatively older ages are inconclusive, some finding no association (Newhouse et al, 1977;Casagrande et al, 1979;Cramer et al, 1983;Lesher et al, 1985), others an increased risk (Joly et al, 1974;McGowan et al, 1979;Hildreth et al, 1981;Franceschi et al, 1982). Only Franceschi et al (1982) found the increased risk to be statistically significant and independent of parity.…”

“…We also found that the greater the number of incomplete pregnancies the lower the risk, although the trend was not significant. Most other studies have not investigated if women of low gravidity have an increased risk of ovarian cancer because of reduced fertility or because of voluntary limitation of family size, although Joly et al (1974), McGowan et al (1979) and Nasca et al (1984) found a higher risk in women who had tried to conceive but had failed. Our findings also suggest that infertility is a risk factor for ovarian cancer.…”

Cancer in the Gizan Province of Saudi Arabia: An Eleven Year Study

“…Epidemiological studies have indicated that ovarian cancer is more common in women with lower mean number of pregnancies, in those never pregnant and in those with a history of infertility. 39 Early age of marriage and multiple pregnancies is the norm among Saudi females and this seems to have a protective effect. Low prevalence of cervical cancer in Saudi Arabia has been attributed to lack of sexual promiscuity and male circumcision, although Rabadi has reported a rising incidence from the Dhahran Health Center.…”

Hormonal aspects of epithelial ovarian cancer: review of epidemiological evidence

“…In line with both the 'incessant ovulation' and the 'gonadotrophin' hypotheses, pregnancy is expected to reduce the risk of epithelial ovarian cancer. One of the most consistent findings in ovarian cancer epidemiology is the protective effect of full-term pregnancies on epithelial ovarian cancer risk (Joly et al, 1974;Newhouse et al, 1977;Annegers et al, 1979;Casagrande et al, 1979;Miller et al, 1980;Hildreth et al, 1981;Byers et al, 1983;Cramer et al, 1983;Nasca et al, 1984;Tzonou et al, 1984;Voigt et al, 1986;Wu et al, 1988;Kvåle et al, 1988;McGowan et al, 1988;Mori et al, 1988;Booth et al, 1989;Franceschi 1989;Hartge et al, 1989;Shu et al, 1989;Gwinn et al, 1990;Negri et al, 1991;Lund, 1992;Whittemore et al, 1992;Chen et al, 1992;John et al, 1993;Polychronopoulou et al, 1993;Adami et al, 1994;Baker & Piver, 1994;Risch et al, 1994;Albrektsen et al, 1996). Parous women compared to nulliparous have relative risk estimates in the range of 0·3-0·7 (Annegers et al, 1979;Casagrande et al, 1979;Mori et al, 1988;Shu et al, 1989;Negri et al, 1991;Whittemore et al, 1992;Polychronopoulou et al, 1993).…”