Minimal Infiltrative Disease Identification in Cryopreserved Ovarian Tissue of Girls with Cancer for Future Use: A Systematic Review

SIMPLE SUMMARY: Cryopreservation of ovarian tissue and transplantation are the only available fertility techniques to preserve fertility and endocrine function for prepubertal girls with cancer who require immediate cancer treatment. The primary objective of this systematic review was to identify and critically appraise the existing evidence regarding targeted minimal infiltrative disease detection in harvested ovarian tissues and identify markers that may be of value for assessment before autotransplantation, thereby facilitating fertility restoration in childhood cancer survivors. While the majority of malignancies were found to be at low risk of containing malignant cells in ovarian tissue, more studies are needed to ensure safe implementation of future fertility restoration in clinical practice. ABSTRACT: Background: Ovarian tissue cryopreservation and transplantation are the only available fertility techniques for prepubertal girls with cancer. Though autotransplantation carries a risk of reintroducing malignant cells, it can be avoided by identifying minimal infiltrative disease (MID) within ovarian tissue. Methods: A broad search for peer-reviewed articles in the PubMed database was conducted in accordance with PRISMA guidelines up to March 2023. Search terms included ‘minimal residual disease’, ‘cryopreservation’, ‘ovarian’, ‘cancer’ and synonyms. Results: Out of 542 identified records, 17 were included. Ovarian tissues of at least 115 girls were evaluated and categorized as: hematological malignancies (n = 56; 48.7%), solid tumors (n = 42; 36.5%) and tumors of the central nervous system (n = 17; 14.8%). In ovarian tissue of 25 patients (21.7%), MID was detected using RT-qPCR, FISH or multicolor flow cytometry: 16 of them (64%) being ALL (IgH rearrangements with/without TRG, BCL-ABL1, EA2-PBX1, TEL-AML1 fusion transcripts), 3 (12%) Ewing sarcoma (EWS-FLI1 fusion transcript, EWSR1 rearrangements), 3 (12%) CML (BCR-ABL1 fusion transcript, FLT3) and 3 (12%) AML (leukemia-associated immunophenotypes, BCR-ABL1 fusion transcript) patients. Conclusion: While the majority of malignancies were found to have a low risk of containing malignant cells in ovarian tissue, further studies are needed to ensure safe implementation of future fertility restoration in clinical practice.