Fertility Treatment and Cancer Risk: No Consistent Evidence of Increased Risk
Based on the highest quality guideline evidence, there is no consistent evidence that fertility treatments increase cancer risk, even in hormonally sensitive tumors. The available data are reassuring regarding the safety of fertility preservation methods and subsequent pregnancy in cancer survivors.
Key Evidence on Fertility Treatment and Cancer Risk
No Increased Cancer Risk from Fertility Interventions
Data are limited, but there appears to be no increased risk of cancer recurrence from fertility preservation methods or pregnancy, even in hormonally sensitive tumors 1.
Multiple ASCO guidelines consistently state that there is no detectable increased risk of disease recurrence associated with most fertility preservation methods and pregnancy, including in hormonally sensitive cancers 1.
Studies do not indicate increased cancer recurrence risk as a result of aromatase inhibitor-supplemented ovarian stimulation and subsequent pregnancy 1.
Safety of Pregnancy After Cancer Treatment
For breast cancer survivors specifically, pregnancy is considered safe and the hormonal environment associated with pregnancy is not thought to increase the risk of breast cancer recurrence 1.
Prior breast cancer treatment does not increase the future risk of congenital malformations in offspring 1.
Available studies, including large registry studies, have revealed no increased risk of genetic abnormalities, birth defects, or cancers in the children of cancer survivors, aside from hereditary syndromes 1.
Important Caveats and Nuances
Infertility Itself as a Potential Risk Factor
Some research suggests that infertility itself (independent of treatment) may be associated with certain cancer risks, particularly for ovarian and endometrial cancers in women with ovulatory disorders 2.
Nulliparity has been consistently associated with increased rates of ovarian tumors, particularly borderline and endometrioid cancers in patients with a history of endometriosis 2.
Women affected by infertility may be at higher risk for endometrial cancer, particularly if affected by ovulatory disorders 2.
Fertility Medications: Reassuring but Complex Data
Although early studies suggested that infertility medications were associated with increased risk of ovarian cancer, subsequent studies have been mainly reassuring 2.
The Practice Committee Guidelines of the American Society of Reproductive Medicine acknowledge that although the relationship is complex, no additional risk of breast cancer has been consistently linked to infertility medications 3.
The relationship between fertility drugs and epithelial ovarian cancer remains controversial, and causality has yet to be proven 4.
Clinical Implications
Counseling Patients
When discussing fertility preservation with cancer patients, clinicians should emphasize:
The risk of cancer from fertility treatments themselves appears negligible based on current evidence 1.
Any theoretical concerns about hormonal stimulation in estrogen-sensitive cancers can be mitigated by using aromatase inhibitor-based stimulation protocols 1.
The benefits of fertility preservation for quality of life and psychosocial well-being typically outweigh any theoretical cancer risks 1.
Distinguishing Treatment Effects from Disease Effects
It is critical to distinguish between cancer risk from fertility treatments versus risk from underlying infertility conditions 2.
Patients with pre-existing ovulatory disorders or endometriosis may have baseline elevated cancer risks independent of any fertility interventions 2.
Common Pitfalls to Avoid
Do not conflate infertility as a condition with fertility treatment as an intervention - they have different risk profiles 2.
Do not delay fertility preservation discussions due to unfounded cancer concerns - the evidence supports the safety of these interventions 1.
Do not assume that pregnancy after cancer increases recurrence risk - this is not supported by available data, even in hormonally sensitive tumors 1.