(P 270) FEASIBILITY OF FERTILITY PRESERVATION IN CHILDREN, ADOLESCENTS AND YOUNG ADULTS WITH SARCOMAS - A PROSPECTIVE COHORT STUDY WITH LONG-TERM FOLLOW-UP

Objective: To report the long-term experience with fertility preservation (FP) in patients with sarcomas and their reproductive outcomes.

Methods: The program for FP of Karolinska University Hospital, Stockholm, Sweden, is tax-funded, and it has included adolescents and young adults (AYAs) with cancers. Hereby we report on the patient diagnosed with sarcomas between 1999 to 2024, their clinical characteristics, treatment received, FP methods chosen, outcome of fertility preservation, and reproductive outcome in females.

Results: During the study period, 76 males and 75 females, 63% with bone sarcomas and 27% with soft tissue sarcomas, received counseling for FP. The mean age was 19 years at the time of cancer diagnosis and one third of the patients were pre-pubertal.
In total, 89% of males underwent FP by semen banking (N=66) or testis biopsies (N=2), whereas 73% of females underwent oocyte/embryo (N=20) or ovarian tissue cryopreservation (N=35). Fourteen females that did not undergo FP at time of diagnosis and showed signs of maintained ovarian function at teenage, underwent FP and cryopreserved oocytes post-cancer treatment.
Most survivors in the cohort are still young. Six adult women have attempted pregnancy and five have delivered children, one after transplantation of ovarian tissue, four after using of cryopreserved specimens in assisted reproductive treatment and one after natural conception.

Conclusion: Most patients in the cohort accessed FP directly after receiving their cancer diagnosis, however, semen banking was easily planned and most males could access it, whereas the need of invasive methods, hormone treatment and interventions for female FP resulted in lower uptake of this methods early after diagnosis. However, adolescent girls presenting with signs of ovarian function could be offered FP afterwards, indicating the need of surveillance of gonadal function in these patients. Most patients in the cohort are still young, thus longer follow-up is warranted.