Fertility preservation is a crucial aspect of care for oncological patients undergoing gonadotoxic treatments such as chemotherapy, radiotherapy, or surgery, which can significantly reduce ovarian reserve and cause infertility or premature menopause. Among available techniques, oocyte cryopreservation is well-established with high survival rates but requires controlled ovarian stimulation and may not be suitable for prepubertal patients or those needing urgent cancer therapy. Ovarian tissue cryopreservation offers advantages by preserving a larger number of primordial follicles, can be performed anytime in the menstrual cycle regardless of age, and also helps restore ovarian endocrine function.

Combining ovarian tissue cryopreservation followed by oocyte cryopreservation may maximize fertility preservation by safeguarding more follicles and ensuring availability of mature oocytes.

This study will collect data from two patient groups:

Group 1: patients undergoing ovarian tissue cryopreservation followed by oocyte cryopreservation (combined treatment)

Group 2: patients undergoing oocyte cryopreservation alone.

Group assignment is based on planned gonadotoxic therapy and available time before treatment initiation, according to clinical practice.

The study aims to compare the number of oocytes retrieved per ovarian stimulation cycle between the two groups, along with the oocyte retrieval rate (number of oocytes retrieved/number of aspirated follicles), number of mature oocytes (metaphase II), incidence of moderate ovarian hyperstimulation syndrome within 7 days post-retrieval, and correlations between serum estradiol and luteinizing hormone levels on trigger day and oocyte yield.

Approximately 127 patients aged 18 to 46 will be consecutively enrolled at the UO Gynecology and Human Reproduction Pathophysiology, IRCCS AOUBO Policlinico di Sant'Orsola. This is a cross-sectional, single-center, observational study with both retrospective and prospective enrollment. The retrospective period considered is from January 1, 2022, to the study start date. The study duration is 4 years and 3 months.

Inclusion Criteria:

• Patient with oncological disease eligible for potentially gonadotoxic therapy
• BMI ≥ 17.5 kg/m² and ≤ 32 kg/m²
• Age ≥ 18 years and ≤ 46 years

Exclusion Criteria:

• Hypersensitivity to one or more of the active substances used during ovarian stimulation treatment
• Positive for HBV, HCV, HIV, or Treponema pallidum
• Lack of oncological clearance

Patients diagnosed with oncological disease attending the UO Gynecology and Human Reproduction Pathophysiology, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Policlinico di S. Orsola, for fertility preservation through ovarian tissue cryopreservation and/or oocyte cryopreservation.