Breast cancer incidence after hormonal infertility treatment in Sweden: a cohort study

• OBJECTIVE: To assess the impact of infertility treatment with causes of infertility on incidence of breast cancer. STUDY DESIGN: Historical prospective cohort study of 1135 women attending major university clinics for treatment of infertility in Sweden, 1961-1976. Women were classified as users of clomiphene citrate or gonadotropins, or a combination of both therapies. Standardized incidence ratios were calculated to estimate relative risk of breast cancer. RESULTS: We observed 54 cases of breast cancer during 1961-2004, which did not significantly exceed those expected. Users of high-dose clomiphene citrate had an almost 2-fold increased risk (standardized incidence ratio, 1.90; 95% confidence interval, 1.08-3.35). This association was more pronounced among women referred for nonovulatory factors, with 3-fold increased risk (standardized incidence ratio, 3.00; 95% confidence interval, 1.35-6.67). CONCLUSION: No overall increased risk for breast cancer was shown with infertility treatment. Women with nonovulatory causes treated with high-dose clomiphene citrate therapy may have an elevated risk for breast cancer.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Reproduktionsmedicin och gynekologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Obstetrics, Gynaecology and Reproductive Medicine (hsv//eng)

Keyword

Adult

Breast Neoplasms/*chemically induced/epidemiology

Chorionic Gonadotropin/*adverse effects/therapeutic use

Clomiphene/*adverse effects/therapeutic use

Cohort Studies

Female

Fertility Agents

Female/*adverse effects/therapeutic use

Humans

Incidence

Infertility

Female/*drug therapy

Prospective Studies

Sweden/epidemiology

ovulation induction

postmenopausal women

fertility drugs

risk

therapy

health

carcinogenesis

prevention

pregnancy

estrogens

Incidence

MEDICINE

Publication and Content Type

ref (subject category)

art (subject category)