Prognostic data in fertility preservation: the role of preimplantation genetic testing for aneuploidy (PGT-A) among cancer patients undergoing embryo banking (EB)

Abstract

Patients with cancer may overestimate FP success rates a. PGT-A aids in embryo selection and may provide a more accurate picture of future reproductive potential among banked embryos. We investigated the use of PGT-A among patients undergoing EB cycles for FP prior to cancer treatment. Retrospective cohort study of medical EB cycles between 1/2014 and 4/2018. Analysis of medical EB cycles performed in patients with cancer. PGT-A performed using trophectoderm biopsy with aCGH or NGS. Exclusive oocyte cryopreservation cycles were excluded. Data analyzed using student’s T-test, chi square, and Fishers Exact test (mean ± SD, p<0.05). 58 medical EB cycles were identified and compared; 34 cycles (59%) utilized PGT-A. 67% of patients banking embryos for breast cancer (18/27) utilized PGT-A; patients with lymphoma, endometrial ca, ovarian ca, and other cancers were evenly divided between PGT-A and no-PGT. PGT-A utilization increased over the study period. PGT-A and no-PGT groups were similar when comparing age (y) at FP cycle start (34.2±4 vs 35.5 ± 6), days of stimulation (11.8 ±2 vs. 11.1 ± 2), days from initial FP consultation to initiation of cancer treatment (36.9 ± 26 vs 36.4 ± 28), and timing of EB cycle start including day-2 or random-start protocol (p>0.05). Equal patients in each group cryopreserved both oocytes and embryos (n=5 PGT-A vs n=3 no-PGT). Groups were similar in no. oocytes retrieved (19 ±15 vs 17.5 ±14), 2PN zygotes (10.7 ± 9 vs 10 ± 9), and blastocysts (7.2 ± 7 vs 6.7 ± 5) excluding 6 patients in the no-PGT group who cryopreserved 2pn zygotes and 4 who froze an average of an additional 10.8 un-biopsied embryos (p>0.05). 5 PGT-A patients underwent a 2nd EB cycle (vs 2 among no-PGT); 2 for poor response, 3 for low or no euploidy. 6 in the no-PGT group cryopreserved 2PN zygotes; 3 were BRCA-positive and intended future PGT-M. Among PGT-A patients, 6.7 ± 5 blastocysts underwent PGT-A with 3.5 ± 3 (48.2%) euploid embryos available for future frozen embryo transfer (FET). Overall, PGT-A patients understood their final “usable” embryo number to be 3.5 ± 3 euploid embryos vs 7.2 ± 7 untested embryos in the non-PGT group. 2 breast cancer survivors in the PGT-A group have since undergone FET with 1 livebirth and 1 ongoing pregnancy; 2 others intend an upcoming FET. PGT-A in medical EB cycles provides critical information about future embryo potential and may be a helpful counseling tool. In some cases, poor PGT-A results informed patients to pursue a 2nd EB cycle without delaying cancer treatment. FP patients without PGT-A have a greater number of vitrified embryos but with unknown reproductive potential; patients may thus overestimate future success rates with devastating consequences. PGT-A results may require patients to prematurely address a terminal fertility diagnosis. The knowledge gained from PGT-A must thus be weighed against the financial cost and possible emotional toll; additional psychosocial support should be offered given the potential magnitude of information gained.