Ovarian Tissue Preservation

• In OTC, a portion of ovarian tissue—typically cortical strips from one ovary—is surgically removed (often via laparoscopy). Memorial Sloan Kettering Cancer Center+2Baylor College of Medicine+2

• The removed tissue is processed in the laboratory: sliced into thin fragments containing dormant primordial follicles, equilibrated with cryoprotectants, and cryopreserved. PMC+2kofinasfertility.com+2

• The tissue is stored long-term in liquid nitrogen under strict cryostorage conditions.

• At a later time, when the patient is ready for fertility, the tissue is thawed and reimplanted (autotransplantation) either onto the remaining ovary or in a heterotopic site (e.g., peritoneal pocket). Once vascularization is established, the tissue may resume follicle growth, hormone production, and ovulation. Baylor College of Medicine+3PMC+3PMC+3

• In some advanced research settings, in vitro follicle maturation (IVM) or culture systems are being studied as a complement or alternative to transplantation. Memorial Sloan Kettering Cancer Center+1

OTC thus aims to preserve both the gonadal endocrine function (estrogen, progesterone) and the follicular/gamete reserve, offering a dual benefit.

Advantages & Indications

When to Use OTC

• Prepubertal patients: Because they are unable to undergo ovarian stimulation and egg retrieval, OTC provides a unique method to preserve fertility. Baylor College of Medicine+2PMC+2

• Urgent cancer therapy: When there is insufficient time (e.g., days) to stimulate and retrieve oocytes, OTC can be done quickly (often within days) without hormonal stimulation delay. kofinasfertility.com+2Memorial Sloan Kettering Cancer Center+2

• When ovarian stimulation is contraindicated: For hormone-sensitive cancers or when the patient’s condition does not permit stimulation or delay.

• Complementary to oocyte/embryo freezing: In many centers, OTC is offered alongside ovarian stimulation to maximize preservation, sometimes combining both in one surgical session (i.e., remove tissue and then stimulate). Wikipedia+2kofinasfertility.com+2

Advantages

• Preservation of a large pool of primordial follicles, potentially more than a single stimulated cycle, especially in younger patients. kofinasfertility.com+2PMC+2

• Restores endocrine function temporarily: after transplantation, the tissue can resume hormone production, potentially delaying menopause or supporting natural cycles. PMC+2PMC+2

• Enables spontaneous conception or IVF post-transplantation, depending on how well the tissue functions. PMC+2PMC+2

• Does not require prior sperm source or partner, giving flexibility.

Technical Challenges & Limitations

Cryopreservation & Tissue Damage

• Freezing and thawing of tissue can lead to follicular loss (via ice crystal formation, osmotic stress, and ischemic injury). PMC+2PMC+2

• Vitrification of ovarian tissue is under investigation; most successful cases so far use controlled slow-freeze protocols, with vitrification still experimental and less validated. kofinasfertility.com+3PMC+3Memorial Sloan Kettering Cancer Center+3

• The stromal and vascular architecture must survive and revascularize post-transplant to sustain follicle survival. PMC+1

Risk of Reintroducing Malignant Cells

• In certain cancers (especially hematologic malignancies, leukemia), there is risk that malignant cells may be present in ovarian tissue. Reimplantation could theoretically reintroduce disease. This must be rigorously assessed and sometimes rules out OTC in high-risk cancers. Memorial Sloan Kettering Cancer Center+2PMC+2

• Strategies to mitigate this risk include rigorous histological/molecular screening, or using isolated follicle culture / in vitro methods (still largely experimental). PMC+1

Duration and Viability

• The functional lifespan of transplanted tissue is finite—some reports suggest 3–7 years of endocrine and fertility function after transplantation. Memorial Sloan Kettering Cancer Center+3Penn Medicine+3PMC+3

• Follicle attrition (loss over time) is inevitable; the more tissue transplanted, the longer potential function. Yale School of Medicine+2PMC+2

Limited Universal Availability

• Relatively few centers in the U.S. currently offer OTC, due to technical, logistical, and regulatory complexity. Baylor College of Medicine+2Memorial Sloan Kettering Cancer Center+2

• Requires close coordination between surgical teams, reproductive labs, and oncology teams.

Clinical Workflow & Protocols

Preoperative Preparation

• Referral occurs immediately after cancer diagnosis, prior to initiating gonadotoxic therapy.

• Baseline ovarian assessment (AMH, antral follicle count) and medical evaluation.

• Oncology input is required to confirm that surgery will not delay cancer treatment.

• Screening for infectious diseases and genetic testing as needed.

Surgical Harvesting

• Typically done via laparoscopy under anesthesia.

• One entire ovary or cortical strips from the ovary are harvested.

• Tissue should be transported promptly to the reproductive laboratory in cold, sterile, buffered medium.

Laboratory Processing & Cryopreservation

• The cortex is dissected into thin slices (~1 mm) to maximize penetration of cryoprotectants and reduce ice damage.

• Tissue pieces are equilibrated in cryoprotectant solutions, sometimes with stepwise concentration changes, then frozen using controlled-rate slow freezing. PMC+2Memorial Sloan Kettering Cancer Center+2

• Thawing and warming protocols must be optimized to avoid thermal shock.

• Fragments are then stored in cryostorage under strict monitoring and backup.

Reimplantation / Use

• When the patient is ready, the tissue is thawed and transplanted (orthotopic or heterotopic).

• Vascular anastomosis or careful placement is used to promote revascularization.

• Monitoring for hormonal recovery and follicle recruitment begins.

• Once functioning, eggs may ovulate naturally or be retrieved for IVF, or embryos may be formed via IVF.

• In advanced settings, in vitro follicle culture may become more viable in the future.

Outcomes & Success Metrics

• Over 130–200 live births have been reported to date after ovarian tissue transplantation. Penn Medicine+3PMC+3PMC+3

• Many patients recover endocrine function; time to hormone recovery is typically months. PMC+2PMC+2

• Reported live birth rates vary; studies suggest approximately 25–40% of women who attempt fertility with transplanted tissue achieve pregnancy. Penn Medicine+2Memorial Sloan Kettering Cancer Center+2

• Functional lifespan is finite; endocrine function may last several years depending on amount and quality of tissue transplanted. Memorial Sloan Kettering Cancer Center+3Penn Medicine+3PMC+3

• Success is better when harvesting at younger ages, with greater tissue volume, and minimal damage during processing.

Risks & Considerations

• Surgical risks: bleeding, infection, anesthesia complications.

• Ischemic injury during revascularization.

• Potential reintroduction of malignant cells (especially in certain cancers).

• Follicle attrition over time; diminishing returns with repeated transplantation.

• Uncertainty in predicting how much functional tissue returns.

Best Practices & Expert Tips

1. Early referral is critical. Delays reduce the window of opportunity.

2. Maximize volume harvested (within safety) to prolong functional life post-transplant.

3. Optimize tissue handling: minimize ischemia time, use high-quality buffers, and maintain proper temperature during transfer.

4. Screen rigorously for malignant cell contamination before reimplantation.

5. Combine with other preservation strategies (e.g., egg freezing) when possible to hedge risk.

6. Choose experienced centers with proven ovarian tissue banking and transplantation outcomes.

7. Track outcomes and contribute to registries to refine the evidence base over time.