P-415 Cryostorage of human ovarian tissue: Evaluating the storage and disposal pattern of a 22-year period with 2475 patients
Authors: John J , Schallmoser A , Einenkel R , Faerber C , Hueren V , Pougin A , Emrich N , Saenger N 
Published: June 2023

Abstract

Study question
What are the characteristics of patients who did ovarian tissue cryopreservation?

Summary answer
Patients store their ovarian tissue in average 5 years, when storage is actively ended about 50% of the patients conceived without using the frozen tissue.

What is known already
In female fertility protection two major options for cryopreservation are available today: cryopreservation of oocytes and ovarian tissue cryopreservation (OTC). If cryopreservation of oocytes is not feasible, OTC remains the only option for individual fertility protection in women, adolescents and especially prepubertal girls.

Study design, size, duration
The relevant parameters of a single university center were revised and digitalized in the period from 2019 to 2021 and were analyzed in the time period between 2000 and 2021.

Participants/materials, setting, methods
2475 patients with stored ovarian tissue were analyzed. Data extraction was done with MedITEX (CRITEX) and processed with SPSS (IBM). To assess the patient motivation of storage, patients were contacted by letter, e-mail and telephone calls.

Main results and the role of chance
On average, patients were aged 26.8 years, diagnosed with breast cancer (44.8%) and lymphoma (22.4%) in majority. In the active storage group (n = 1320) patients were storing for 5.4 years, patient age was 25 years at time of OTC and indications were breast cancer (37.6%) and lymphoma (26.7%). Analyzing the longtime storage group ≥10 years (n = 148), patient age was 23.8 years at time of OTC, storage duration was 12 years and indications were again mainly breast cancer (27%) and lymphoma (27.7%). When patients deceased (n = 133), patient age was 28.1 years, with a storage duration of 2.7 years and initially diagnosed with breast cancer (39.8%) and sarcoma (17.3%). When storage ended (n = 1155), patients stored for 4.2 years, mean age was 33 years.
Analyzing the mode of storage end we observed that 2.5% had a transplantation on site, 10.3% transferred their tissue to another cryobank while 11.5% deceased. The majority of this group (75.7%) ended their storage due to pregnancy (49.1%), no desire to have children (25.9%), too expensive storage fees (8.9%), death (8.5%), recurrence of cancer (8.5%), no partner (4%) and fear of surgery in the future (3.1%). 6.7% regretted the end of storage retrospectively.

Limitations, reasons for caution
Live birth rate was not part of this paper as our main intention was to explore the storage characteristics. Few patients transferred a part of the samples for retransplantation while still storing tissue on site. The response rate of 28.8% limits the scope for interpretation regarding end of storage.

Wider implications of the findings
The pregnancy rate resulting from ovarian tissue that wasn't removed for OTC (49,1%) supports the approach of removing only 50% of one ovary. The long storage time and the fact that 6.7% regretted the end of storage, shows how important the OTC is, it should be covered by health insurances.

Trial registration number
not applicable