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Risks of fertility preservation treatments

Throughout treatment, we work closely with the team planning cancer treatment, to minimise any risk to the patient or delay to their cancer treatment.

1. Delay to cancer treatment

When the intention is to freeze eggs or embryos, ovarian stimulation can start at any time in the menstrual cycle as there is no need to ensure that the lining of the womb is at the same stage of the cycle as the ovaries. However, ovarian stimulation takes a minimum of just over two weeks. It is therefore crucial that patients are referred as early as possible in their treatment pathway to give them the opportunity to consider fertility treatment if they wish without delay to their oncology treatment. In some cases, such as acute leukaemia, any delay to the start of chemotherapy may be significantly detrimental and these patients are not able to freeze eggs or embryos although male patients would usually have time to freeze a semen sample.

2. Risk of high oestrogen levels during stimulation

High levels of oestrogen are seen during ovarian stimulation cycles. This could pose a risk to women diagnosed with an oestrogen sensitive breast cancer. Addition of the drug Letrozole is associated with significantly lower oestrogen levels and we use this routinely for oestrogen positive breast cancer patients. There are no large, long term follow studies, but early data has not demonstrated an increased risk of recurrence or disease progression in these patients.

3. Risk from egg retrieval

There is a potential risk for patients with ovarian malignancies that, following egg collection, there could be a spill of malignant cells from the ovary into the peritoneal cavity, although in practice this is rarely thought to be significant. We always discuss this with the oncologist to minimise risk.

4. Ovarian hyperstimulation syndrome (OHSS)

OHSS is a complication seen in approximately 1% of patients undergoing a cycle of ovarian hyperstimulation for egg recovery. The risk is no higher in fertility preservation patients, but we usually continue with drug therapy for one week after egg collection to try to reduce the risk further, so that the woman is in the best position to commence her oncology treatment.