P-479 Oocyte morphology in cancer patients undergoing fertility preservation
Authors: Sokolova I , Martirosyan Y , Nazarenko T , Biryukova A , Dmitrieva I , Sukhih G 
Published: June 2022

Abstract

Study question
The aim of this study was to evaluate the influence of oncological disease on oocyte morphology in patients undergoing fertility preservation (FP) before cancer treatment.

Summary answer
Oncological disease could be a risk factor for oocyte dysmorphology, considering higher incidence of dysmorphisms in patients with hematological cancer and BRCA mutation carriers.

What is known already
The data on the effect of oncological disease and the type of cancer on ovarian stimulation outcomes are still limited.There is evidence about a higher incidence of alterations in oocyte morphology among pantients indergoing fertility preservation, most of them attribute it to the use of letrozole. However the clinical impact of cancer on the incidence of oocyte dismorphysms and the following IVF outcomes is unclear. The published studies highlight the importance of establishing the influence of such factors on the oocyte quality.

Study design, size, duration
This prospective clinical trial was conducted at the V.I. Kulakov Scientific Research Center for OG&P in Russia. Patients with cancer who had requested oocyte and/or embryo retrieval and cryopreservation prior to cancer treatment were included in the study. A total of 240 patients were selected for the study. All patients signed an informed consent form approved by the ethics committee before participating in the study.

Participants/materials, setting, methods
The patients were divided into 5 groups: group I (n = 65) included patients with breast cancer; group II (n = 35) - cervical cancer; group III (n = 48) - hematologic cancer and group IV (n = 40) - other types of cancer. Group V (n = 52) consisted of comparable patients with tubal factor of infertility. We analysed characteristics of oogenesis and embryogenesis.
We observed the features of cytoplasm, zona pellucida and the perivitelline space and polar bodies of human oocytes.

Main results and the role of chance
The mean age, BMI and AMH did not differ among groups.
The number of mature oocytes obtained was significantly lower in all groups with cancer (I-553 (68.6%), II-239 (77.4%), III-394 (76.4%) and IV-267 (71.0%)) compared to 312 (75%) in the control group (p = 0.005). As it can be seen from the data, patients with breast cancer had a large number of immature and degenerated oocytes. Moreover, the frequency of suoocyte dysmorphysms (such an increased perivitelline space (p = 0.007), an irregular zona pellucida (p &lt; 0.001)) was higher. These changes may be associated with the prescription of aromatase inhibitors to the group of patients. The presence of cytoplasmic vacuoles in the oocytes in the group of patients with hematologic cancer was also significantly higher (p &lt; 0.001).
An important step in the work was to analyze the number and quality of oocytes obtained from BRCA-positive breast cancer patients. The present study included 18 women with BRCA-positive breast cancer.
The number of degenerated oocytes and oocytes with necrotic cytoplasmic areas was significantly higher in the group of patients carrying a germinal mutation in the BRCA gene.

Limitations, reasons for caution
the findings of our study suggest that women with cancer undergoing FP achieve similar oocyte yields as women with no cancer, although those with hematological cancer and BRCA mutation carriers have more frequent changes in oocyte morphology.

Wider implications of the findings
Our findings contribute to preexisting evidence that FP should be offered to pre-menopausal women diagnosed with cancer.

Trial registration number
not applicable