Infertility treatments not associated with increased short-term cancer risk

1. Compared to the general population, women who underwent assisted reproductive technologies (ART) treatments were not at increased risk for developing cancer after approximately 5 years of follow-up.

2. ART treatment was not associated with an increased risk of uterine, ovarian or endocrine cancers and was associated with a reduced risk of breast cancer.

Evidence Rating Level: 2 (Good)

Study Rundown: Use of ART treatments, such as in vitro fertilization, intrauterine insemination and intracytoplasmic sperm injection has steadily grown in the United States over the past two decades. From 2000 to 2012, the number of ART cycles grew more than 75% from 99 629 to 176 247 cycles annually. Certain demographic factors are more common in women undergoing ART treatments and are also risk factors for certain cancers. These include low parity, older age at first birth and a lower incidence of breastfeeding. Moreover, ART can include hormonal therapies which concern some for an increased risk of hormone-sensitive cancers. However, only small observational studies have been conducted on the topic. In 2004, The Society for Assisted Reproductive Technology (SART) made public the SART Clinical Outcome Reporting System (CORS) database, which contains comprehensive data from more than 90 percent of clinics providing ART treatments in the U.S. Researchers in the present study used SART CORS data from large infertility practices in New York, Texas, and Illinois, along with State Cancer Registries, to compare the incidence of cancers among women treated with ART to the incidence of cancers in the general population.

After an average of nearly 5 years of follow-up, the incidence of cancer diagnoses among women who underwent ART treatments did not differ from age-specific general population incidence. Strengths included large, nationally representative population. Limitations included observational study and short follow-up time with regard to the outcome of interest, particularly since cancer diagnoses in reproductive-age women is relatively low. Future investigations might prospectively compare the incidence of new cancer diagnoses in women after ART treatments and in women with infertility who did not undergo ART treatments across a longer duration of follow-up.

Click to read the study in Fertility and Sterility

Relevant Reading: Causes of Infertility as Predictors of Subsequent Cancer Risk

In-Depth [prospective cohort study]: Using the SART database, researchers collected information on 113 226 women in New York, Texas, and Illinois who underwent ART treatment cycles from 2004-2009. Cancer diagnoses were detected in state cancer registries with mean follow-up of 4.87 years. The main outcome was diagnosis of cancer. Cancer incidence in women who underwent ART treatments was compared to state and age-matched cancer incidence in the general population to generate standardized incidence ratios (SIR).

Among 53 782 women undergoing ART treatments, 450 developed cancer over the follow-up period. Compared to state and age-matched omen who underwent ART had a lower risk for all cancers (SIR: 0.78, 95% CI: 0.73-0.83), breast cancer (SIR: 0.83, 95% CI: 0.75, 0.91) and all female genital cancers compared to state and age-matched cancer incidence estimates in the general population. Results were not modulated by parity, number of cycles, or cumulative follicle-stimulating hormone (FSH) dosage.

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