Normal Ovarian Reserve During Long-Term Osimertinib Therapy in a Patient With Li-Fraumeni Syndrome: A Case Report and Literature Review.

In contrast to the well-studied gonadotoxicity of traditional chemotherapy, data on the long-term effects of newer targeted molecular therapies on human ovarian reserves and fertility remain scarce. Here, we report the effect of osimertinib on ovarian reserve. Osimertinib is a third-generation, irreversible tyrosine kinase inhibitor that selectively targets epidermal growth factor receptor (EGFR)-mutant tumors and is used to treat EGFR-positive non-small cell lung cancer (NSCLC). We present a 30-year-old woman with a history of Li-Fraumeni syndrome (LFS), NSCLC, and a large fumarate hydratase-deficient uterine fibroid who was referred for fertility counseling and preservation while receiving maintenance osimertinib. Ovarian reserve was assessed using anti-Müllerian hormone (AMH) measurements and serial pelvic ultrasounds to determine the antral follicle count. Monitoring over 36 months of osimertinib therapy showed a normal ovarian reserve, as evidenced by normal AMH levels and a stable antral follicle count. We demonstrate a normal ovarian reserve in a patient receiving long-term osimertinib treatment. Despite a preserved ovarian reserve, patients on targeted molecular therapies for high-penetrance genetic cancers still face significant reproductive challenges. These challenges include the need for preimplantation genetic testing for monogenic disorders (PGT-M) to reduce the risk of transmitting cancer-predisposition gene mutations to their offspring and the consideration of a gestational carrier, as current guidelines prohibit pregnancy during targeted molecular therapy. Maintaining a normal ovarian reserve would allow the opportunity to delay in vitro fertilization (IVF) until a more optimal time, thereby improving reproductive planning for patients who already manage the burdens of hereditary cancer syndrome.