The impact of parity, infertility and treatment with fertility drugs on the risk of ovarian cancer. A survey

Use of fertility drugs and risk of ovarian cancer

PURPOSE OF REVIEW

The purpose of this review is to highlight recent research and insights into the relationship between fertility drug use and ovarian cancer risk.

RECENT FINDINGS

Results from two large case-control studies provided further evidence that fertility drug use does not significantly contribute to risk of ovarian cancer among the majority of women when adjusting for known confounding factors. However, questions regarding the effect on certain subgroups, including long-term fertility drug users, women who remain nulligravid after fertility treatment, women with BRCA1 or BRCA2 mutations and borderline ovarian tumours, still remain. In addition, it may currently just be too early to determine whether there is an association between fertility drug use and ovarian cancer risk given that many of the exposed women are only now beginning to reach the ovarian cancer age range.

SUMMARY

Whether use of fertility drugs increases the risk of ovarian cancer is an important question that requires further investigation, in particular given the large number of women utilizing fertility treatments. Fortunately, results from recent studies have been mainly reassuring. Large well designed studies with sufficient follow-up time are needed to further evaluate the effects of fertility treatments within subgroups defined by patient and tumour characteristics.

Fertility drug use and the risk of ovarian tumors in infertile women: a case-control study

OBJECTIVE

To assess the influence of infertility and fertility drugs on risk of ovarian tumors.

DESIGN

Case-control study (Mayo Clinic Ovarian Cancer Study).

SETTING

Ongoing academic study of ovarian cancer.

PATIENT(S)

A total of 1,900 women (1,028 with ovarian tumors and 872 controls, frequency matched on age and region of residence) who had provided complete information in a self-report questionnaire about history of infertility and fertility drug use.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Effect of infertility history, use of fertility drugs and oral contraception, and gravidity on the risk of ovarian tumor development, after controlling for potential confounders.

RESULT(S)

Among women who had a history of infertility, use of fertility drugs was reported by 44 (24%) of 182 controls and 38 (17%) of 226 cases. Infertile women who used fertility drugs were not at increased risk of developing ovarian tumors compared with infertile women who did not use fertility drugs; the adjusted odds ratio was 0.64 (95% CI, 0.37, 1.11). The findings were similar when stratified by gravidity and when analyzed separately for borderline versus invasive tumors.

CONCLUSION(S)

We found no statistically significant association between fertility drug use and risk of ovarian tumors. Further larger, prospective studies are needed to confirm this observation.

Ovarian cancer: etiology, risk factors, and epidemiology

Little is known regarding the early aspects of ovarian carcinogenesis. As a consequence, the identification of women at risk for the disease is based primarily on clinical grounds, with family history being the most important risk factor. In this review, we will discuss the various hypotheses regarding ovarian etiology and pathogenesis. In addition, we will discuss the epidemiology of ovarian cancer, including hereditary, reproductive, hormonal, inflammatory, dietary, surgical, and geographic factors that influence ovarian cancer risk.

Use of fertility drugs and risk of ovarian cancer: results from a U.S.-based case-control study

BACKGROUND

Previous studies examining associations between use of fertility drugs and ovarian cancer risk have provided conflicting results. We used data from a large case-control study to determine whether fertility drug use significantly impacts ovarian cancer risk when taking into account parity, gravidity, and cause of infertility.

METHODS

Data from the Hormones and Ovarian Cancer Prediction (HOPE) study were used (902 cases, 1,802 controls). Medical and reproductive histories were collected via in-person interviews. Logistic regression was used to calculate ORs and 95% confidence intervals (CI). Models were adjusted for age, race, education, age at menarche, parity, oral contraceptive use, breastfeeding, talc use, tubal ligation, and family history of breast/ovarian cancer.

RESULTS

Ever use of fertility drugs was not significantly associated with ovarian cancer within the total HOPE population (OR, 0.93; 95% CI, 0.65-1.35) or among women who reported seeking medical attention for infertility (OR, 0.87; 95% CI, 0.54-1.40). We did observe a statistically significant increased risk of ovarian cancer for ever use of fertility drugs among women who, despite seeking medical attention for problems getting pregnant, remained nulligravid (OR, 3.13; 95% CI, 1.01-9.67).

CONCLUSIONS

These results provide further evidence that fertility drug use does not significantly contribute to ovarian cancer risk among the majority of women; however, women who despite infertility evaluation and fertility drug use remain nulligravid, may have an elevated risk for ovarian cancer.

IMPACT

Our results suggest that fertility drug use does not significantly contribute to overall risk of ovarian cancer when adjusting for known confounding factors.

Intraperitoneal serous adenocarcinoma: a critical appraisal of three hypotheses on its cause

OBJECTIVE

Serous ovarian, Fallopian tube, and peritoneal adenocarcinomas are remarkably similar, both in their morphology, as well as in their clinical behavior. Despite extensive clinical and fundamental research, controversy still exists on the origin of serous female adnexal tumors. Difficulties in identification of site of origin at late stage the of disease at detection, when ovary, Fallopian tube, and the abdominal cavity are usually all involved, in addition to their macroscopic and microscopic resemblance, are major causes of this debate. In 3 hypotheses, 3 possible tissues of origin are proposed: the ovarian surface epithelium, the Fallopian tube epithelium, and the secondary Mullerian system.

STUDY DESIGN

We searched for all peer-reviewed articles and reviews that examined "serous ovarian carcinoma," "Fallopian tube carcinoma," "Mullerian system," "ovarian surface epithelium," "tubal epithelium," and "peritoneal." We included only articles that could give information on the origin of serous carcinomas. Additional articles were added by examining references of overview articles in relevant fields.

RESULTS

Discussed are the experimental data underlying these hypotheses.

CONCLUSION

An attempt is made to integrate the 3 hypotheses into a comprehensive model of serous intraperitoneal adenocarcinogenesis. It can be concluded that the Fallopian tubes play a major role in the development of female serous cancer.

Assisted Reproductive Technology and the Incidence of Ovarian Cancer: A Meta-Analysis

OBJECTIVE

To systematically evaluate the available literature regarding the relationship between assisted reproductive technology and ovarian cancer.

DATA SOURCES

Computerized search of 6 databases from 1966 (or closest) to present: Cochrane Controlled Trials Register, Cancerlit, CINHAL, Current Contents, PubMed in process (formerly called PreMEDLINE), and MEDLINE. We collected references from the bibliographies of reviews, original research articles, content experts, and conference proceedings to find published and unpublished literature.

METHODS OF STUDY SELECTION

Case-control and cohort studies are included. The population of interest is treated infertile women, the control population is untreated infertile women, and the intervention or exposure of interest includes the following fertility medications: clomiphene citrate, gonadotropins, human chorionic gonadotropin, and gonadotropin releasing hormone agonists. The primary outcome is incident, primary ovarian cancer. Three cohort and 7 case-control studies were included in the quantitative analyses.

TABULATION, INTEGRATION, AND RESULTS

The Newcastle-Ottawa Quality Assessment Scales were used. Two investigators independently extracted study methods, sources of bias, and outcomes. The following information was recorded: publication information, subject characteristics, intervention information and outcomes. Studies combined were sufficiently homogeneous for quantitative summary. Case-control and cohort data showed a significantly elevated risk for exposure of infertility medications and ovarian cancer in subjects who underwent assisted reproductive technology compared with general population controls (1.52; 95% confidence interval [CI] 1.18 to 1.97). When cases of ovarian cancer were compared with infertile controls for exposure to infertility medications, the odds ratio (0.99; 95% CI 0.67, 1.45) was not elevated. However, cohort data comparing outcome in treated infertile patients with untreated infertile patients suggests that treated patients may tend to a lower incidence of ovarian cancer-odds ratio = 0.67 (95% CI 0.32, 1.41).

CONCLUSION

Ovarian cancer does not appear to be increased in treated infertile patients versus untreated infertile patients. Treated infertile patients may have a lower incidence of ovarian cancer than untreated infertile patients.

Fertility preservation in gynecologic cancer

SUBJECT

Management of patients with gynecologic cancer can now often be tailored to the extent of the disease and preservation of child-bearing ability and/or sexual function may be possible for certain women with early invasive disease.

METHOD

A better understanding of the tumor-biology, and the consideration of different clinicopathologic factors, that bear prognostic significance in therapeutic modalities, will allow more and more individualization of treatment.

DISCUSSION

Management of young women with early gynecologic cancer should therefore be individualized with the risk of conservative therapy balanced against the dangers and advantages of more radical therapy. Experts in gynecologic oncology and infertility together with an informed patient and her family should make treatment decisions.

OUTCOME

This article will review the conservative surgical management of early invasive cancers of the ovary, cervix and endometrium, in order to help preserve child-bearing capacity. In addition, management of gynecologic cancers diagnosed during pregnancy will also be discussed.

Shared oocyte donation: society's benefits

OBJECTIVE

To assess the efficacy of oocyte donation when a cohort of oocytes is shared between two phenotypically matched recipients.

DESIGN

A retrospective analysis of a program using shared anonymous oocyte donation.

SETTING

Academic infertility center.

PATIENT(S)

Recipient women with partial or complete ovarian failure; oocyte donors who have been properly screened.

INTERVENTION(S)

Each oocyte donor was phenotypically matched with two potential recipients. The cohort of donated oocytes were divided between these two recipients if eight or more mature oocytes were obtained at retrieval. Recipients underwent hormone replacement therapy consisting of down-regulation with a GnRH agonist, transdermal estradiol, and intramuscular progesterone in a dose determined by a previous preparatory cycle.

MAIN OUTCOME MEASURE(S)

Pregnancy and delivery rates for all transfers originating from a cohort of oocytes obtained by retrieval of a single donor; pregnancy and delivery rates per recipient; rate of conversion of a shared donation cycle to a single recipient.

RESULT(S)

A total of 249 donor cycles permitted 241 retrievals. Each recipient received 8.3 +/- 3.5 oocytes per donation. There were 424 fresh ETs and 48 frozen ETs performed. For fresh ETs, clinical pregnancy and ongoing or delivery rates per recipient were 56.8% and 49.7%, respectively. For frozen ETs, these rates were 50% and 39.5%. Implantation rates were 31.8% and 26.1% for fresh and frozen ET, respectively. When analyzed per donor retrieval, clinical pregnancy and ongoing or delivery rates were 109.5% and 95.4%. These high pregnancy rates per donor reflect the numerous fresh and frozen ETs that can result from one donor's retrieval. Conversion of a donation cycle from two recipients to one recipient occurred for 26 of 241 cycles (10.8%).

CONCLUSION(S)

Shared anonymous oocyte donation provides a very high pregnancy rate per donor retrieval that is not achievable with unshared donation. In addition, there is a diminished risk exposure of donors per total completed recipient transfers. We support shared oocyte donation as the most efficient use of the precious resource of human oocytes.

Ovarian cancer in infertility patients

The possibility that ovulation induction increases the risk of ovarian cancer remains unproven. However, recent studies suggest that both infertility and endometriosis may be independent risk factors. Despite the various case reports and epidemiological studies performed the association between the use of infertility drugs and ovarian cancer remains weak. The fact that the women who were the first to use ovulation agents are now reaching mid-life means that future studies should show whether any association exists. Hence, there is a need now for large prospective trials to be performed to establish whether an association between ovulation induction agents and ovarian cancer truly exists.

Cancer in women with infertility

There has been increasing concern in recent years regarding a possible link between drugs given for infertility treatment and the subsequent risk of cancer, particularly ovarian cancer. Recent epidemiological studies reassure us that any effect, if present, is likely to be small, and does not affect women who conceive with such treatment.