Ovarian tissue freezing is an ideal option for these patients as it can be performed immediately and does not need any time for ovarian stimulation. We hope we can develop this service in our locality to allow more young female cancer patients to have their fertility preserved.

To date, transplantation of cryopreserved ovarian tissue has resulted in births of at least 130 children but data on transplantation of ovarian tissue removed before puberty are scarce.

During ovarian tissue cryopreservation (OTC), it is possible to freeze isolated oocytes. In 2003, Revel et al described for the first time oocyte isolation in children younger than 12 years with seven, eight and seven oocytes isolated from the ovarian cortex of patients aged 5, 8 and 10 years, respectively.

At this moment, financial constraint is another great hindrance to fertility preservation in Hong Kong as the procedure is not cheap. Cryopreservation of gametes and embryos involving assisted reproductive technology is expensive and the costs of fertility preservation impose a great burden to these cancer patients on top of the great expenses for their chemo- or radiotherapy. It is almost impossible for underprivileged families.

Young cancer patients may often need immediate gonadotoxic treatment for their cancer, just like those with haematological cancers. In these patients, egg or embryo freezing is not possible as it takes at least 8-12 days' time for ovarian stimulation. Ovarian tissue freezing is an ideal option for these patients as it can be performed immediately and does not need any time for ovarian stimulation. We hope we can develop this service in our locality to allow more young female cancer patients to have their fertility preserved.

Inclusion Criteria:

• Patients aged from 0-35 years old and diagnosed with cancer e.g., leukaemia, myeloproliferative or myelodysplastic diseases, lymphoma, bone tumours, neurological neoplasms and sarcoma, Paediatric bone marrow transplant patients
• Patients with any illness or who will undergo any type of treatment that may cause irreversible damage to their fertility, such as extensive abdominal surgery, high toxicity medication and treatments;
• Patients suffering from hormone-sensitive malignancies who will undergo medical treatment, such as radiotherapy and chemotherapy that is liable to damage their ovaries and deter them from conception in the future.

Exclusion Criteria:

Patients with no anticipated oncologic therapies Patients who are pregnant Children with one ovary Children deemed high risk for perioperative complications Patients unable to provide consent/assent (i.e. significant psychiatric problems/cognitive delay)

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