Fertility preservation in female oncology patients: the influence of the type of cancer on ovarian stimulation response.

STUDY QUESTION: Does the type of cancer influence on the ovarian response to stimulation for fertility preservation (FP) in female oncology patients? SUMMARY ANSWER: Patients with gynaecological cancer have less number of retrieved mature oocytes compared with haematological and breast cancer patients. WHAT IS KNOWN ALREADY: Concerns about the impact of cancer therapy on future fertility have been raised and FP has become an important component in cancer management. Previous studies analysing FP results in cancer patients have shown conflicting findings. STUDY DESIGN, SIZE, DURATION: This was a retrospective analytical study performed in the Centre for Reproductive Medicine, at St Bartholomew's Hospital, between January 2000 and December 2014. The aim of this study was to analyse the response to ovarian stimulation in cancer patients before undergoing cancer treatment and to determine whether any difference can be attributed to underlying cancer diagnosis. We also report the pregnancy outcomes. PARTICIPANTS/MATERIALS, SETTING,
METHODS: A total of 531 female patients recently diagnosed with cancer were referred for counselling on FP. A total of 306 patients underwent ovarian stimulation for oocyte or embryo cryopreservation. We compared the baseline characteristics and ovarian response in five main subgroups: breast cancer, haematological cancer, gynaecological cancer, gastrointestinal cancer and others. The primary outcome was the total number of mature oocytes retrieved and pregnancy outcomes. MAIN RESULTS AND THE ROLE OF CHANCE: The main cancer diagnosis was breast cancer with 145 patients (47.4%); 79 patients (25.8%) had haematological malignancies; 42 (13.7%) had gynaecological malignancies; 20 (6.5%) had gastrointestinal cancer and 20 (6.5%) had other types of cancer. Patients with breast cancer were older (P < 0.001). Patients with haematological malignancies had higher number of mature oocytes retrieved (P = 0.003). The number of mature oocytes retrieved was lower in patients with gynaecological malignancy compared with haematological and breast cancer patients (P = 0.005 and P = 0.045, respectively). The fertilization rate and the number of cycles cancelled were comparable between all the groups. Thirty-two embryo transfer cycles have been done in 22 patients who have returned to attempt pregnancy. Pregnancy rate per transfer cycle was 43.75%, and cumulative pregnancy rate per patient was 54.5%. Live birth rate per patient was 22.72%. LIMITATIONS, REASONS FOR CAUTION: Apart from the retrospective nature of the study, patients were included over the period of 15 years, and over that time technology has changed and protocols have evolved. The results obtained from subcategory analyses should be interpreted with caution, as in each subgroup there are different types of malignancies with different number of patients in different age groups. Different ovarian stimulation protocols were applied. Only a few patients have come back to attempt pregnancy after being cured from their disease. We do not have follow-up data on these patients; as a result, we are not able to report the survival rate and the reason for non-return for embryo transfer. In addition, we cannot report information on spontaneous conceptions and births. Slow freezing used for embryo cryopreservation, high miscarriage rate and low live birth rate per transfer are other limitations of this study. WIDER IMPLICATIONS OF THE
FINDINGS: The current study is the largest series analysing each group of cancer separately and showing pregnancy outcomes in oncology patients undergoing FP. These results provide valuable information about the success of this technique in oncology patients. STUDY FUNDING/COMPETING INTEREST(S): The authors have not received any funding to support this study. There are no conflicts of interest to declare.