Objective:

To analyze the association between medically assisted reproduction (MAR) treatments and hormone-related cancers using an emulated target trial framework.

Approach:

• Study Design: A retrospective emulated target trial design was used, linking Australian state and national data to identify women who received MAR between January 1, 1991 and December 31, 2018.
• Data Collection: Women were identified through records of MAR treatment reimbursement from the Medicare Benefits Scheme and matched with non-exposed individuals based on various factors.
• Bias Assessment: The study included bias assessment through E-values, negative controls, and evaluation of time-varying treatment effects.

Key Findings:

• Recent meta-analyses suggest few to no associations of ART with hormone-related cancer risk in female patients.
• Substantial variability in study designs and confounder adjustments contributes to heterogeneous results.
• Specific studies reported associations between ART and increased risks for certain cancers, including breast, ovarian, and uterine cancers, with notable findings from Vassard et al. on invasive breast cancer and Lundberg et al. on ovarian cancer risk.

Interpretation:

Strong evidence linking MAR treatments to hormone-related cancers is limited, and findings vary significantly across studies.

Limitations:

• The rarity of some cancers and long latency periods complicate the assessment of cancer risk.
• Heterogeneity in study designs and confounding variables affects the reliability of results.
• An error in data extraction led to an imbalance in the number of nulliparous women in the study groups.

Conclusion:

Understanding the risks associated with MAR treatments is critical for patients and healthcare practitioners.