Oral Contraceptive Use and Risk of Gestational Trophoblastic Tumors
Abstract & Commentary
Synopsis: Long duration of oral contraceptive use before conception increases the risk of gestational trophoblastic tumors. However, changes in use of oral contraceptives are not warranted, because the incidence attributable to oral contraceptive use is low.
Source: Palmer JR, et al. J Natl Cancer Inst 1999;91:635-640.
Palmer and associates undertook a multicenter case-control study of gestational trophoblastic tumors to test the hypothesis that long-term use of oral contraceptives before conception may increase the risk of gestational trophoblastic tumors. Telephone interviews were conducted with 235 case patients, including 50 with gestational choriocarcinoma, and 413 control subjects matched on recentness of pregnancy, age at pregnancy, and area of residence. The relative risk estimate for ever having used oral contraceptives before the index pregnancy was 1.9 (95% confidence interval [CI] = 1.2-3.0), and the risk increased with duration of use (P for trend = 0.05). The estimate was highest for women who used oral contraceptives during the cycle in which they became pregnant (relative risk = 4.0; 95% CI = 1.6-10), but there was no consistent pattern, according to the time interval, since last use. Relative risk estimates were similar for choriocarcinoma and persistent mole—2.2 and 1.8, respectively. Control for the number of sexual partners, which was independently associated with risk (P for trend = 0.05), did not materially change the results. Palmer et al concluded that this study, the largest to date, indicates that long duration of oral contraceptive use before conception increases the risk of gestational trophoblastic tumors. They noted, however, that changes in use of oral contraceptives are not warranted because the incidence attributable to oral contraceptive use is low.
Comment by David M. Gershenson, MD
The major findings of this study are that oral contraceptive use increases the risk of gestational trophoblastic disease, and that duration of use was associated with the degree of increased risk. In addition, having had 10 or more sexual partners before the index pregnancy independently doubled the risk. Although this is the largest study to date, several other studies have reported this phenomenon. The pathogenesis of gestational trophoblastic tumors is poorly understood. In their discussion of this article, Palmer et al point out that, in addition to the influence of oral contraceptive use, younger women and perimenopausal women are at higher risk for developing gestational trophoblastic disease. Common in all these situations is either physiologic or exogenous interference with ovulation. The fact that the number of sexual partners also influenced the development of gestational trophoblastic tumors is unexplained. Again, as Palmer et al note, it raises the possibility of a sexually transmitted disease acting as an etiologic agent. Despite the findings of this study, the risk of oral contraceptive use is not great, and no change in our practice appears indicated other than appropriate counseling.
Ever having used oral contraceptives increases a woman’s risk of developing gestational trophoblastic tumors by:
a. twofold.
b. fivefold.
c. tenfold.
d. twentyfold.
e. fortyfold.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content