The objective of a study was to determine the risk of ovarian cancer, including malignant and borderline ovarian tumors, in women who have been exposed to assisted reproductive therapy ( ART ).
Records from the Human Fertilisation & Embryology Authority ( HFEA ) of all women who had assisted reproductive therapy in Britain between 1991-2010, were linked to the National Health Service Central Registers ( NHSCR ) for England, Wales and Scotland to obtain follow up for cancer outcomes, deaths and emigrations.
Cancer incidence in the cohort was stratified by age and calendar period and compared with expectations derived from annual age-specific national rates over the same period. Data were also stratified for potential mediating / moderating factors such as repeated exposures, age at first exposure, parity and subfertility diagnoses.
With 8.8 years average follow-up, 386 ovarian cancers occurred in 255,786 women.
An increased risk of developing an ovarian cancer was observed in the cohort ( standardized incidence ratio [ SIR ] 1.37; 95% CI 1.24-1.51 ).
No increased risk was found with increasing number of cycles of assisted reproductive therapy.
Increasing risk was found with decreasing parity, with women who had no live births by the end of treatment being at greatest risk ( SIR 1.54; 95%CI 1.34-1.76 ).
Risk was increased for women with a female factor cause of infertility ( SIR=1.62; 95% CI 1.42-1.84 ), especially endometriosis ( SIR=2.35; 95% CI 1.80-3.07 ), but male factor only infertility was not associated with risk ( SIR=1.05; 95% CI 0.86-1.28 ).
Younger age at starting assisted reproductive therapy carried greater cancer risk ( P trend less than 0.0001 ).
The risk of developing an ovarian cancer was strongest 0-3 years after first ART cycle ( SIR=1.54; 95% CI 1.27-1.88 ), but no trend with duration since first treatment was observed.
In conclusion, increased ovarian cancer risk was observed in this large cohort of women who had assisted reproductive therapy in Great Britain compared with national rates. The results suggest that this increase is at least partially mediated by patient factors such as low parity and endometriosis.
Certain results argue against an association with assisted reproductive therapy itself ( no increased risk in male factor infertility or with increasing number of cycles ), but others ( increased risk with decreasing age at first exposure and in the first few years after treatment ) leave open the possibility that assisted reproductive therapy might affect risk. ( Xagena )
Source: American Society for Reproductive Medicine ( ASRM ) Annual Meeting, 2015