The Cancer Incidence in Five Continents(CI5)database are jointly maintained by the International Agency for Research on Cancer(IARC)and the International Association of Cancer Registries(IACR),both affiliated to the World Health Organization.This paper provides a histori-cal overview of cancer registration efforts in China,systematically summarizes the journey and en-deavors of Chinese cancer registries as they were incorporated into IARC and CI5.Furthermore,it offers a perspective on the strategies for advancing the high-quality development of cancer registra-tion activities within the nation.

The Cancer Incidence in Five Continents(CI5)database are jointly maintained by the International Agency for Research on Cancer(IARC)and the International Association of Cancer Registries(IACR),both affiliated to the World Health Organization.This paper provides a histori-cal overview of cancer registration efforts in China,systematically summarizes the journey and en-deavors of Chinese cancer registries as they were incorporated into IARC and CI5.Furthermore,it offers a perspective on the strategies for advancing the high-quality development of cancer registra-tion activities within the nation.

Objective:To investigate the effect of luteinizing hormone (LH) levels on the clinical outcome and cumulative live birth rate of in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) fresh embryo transfer in patients with normal ovarian reserve function after application of a flexible protocol of gonadotropin-releasing hormone antagonist (GnRH-A) to promote ovulation with the addition of GnRH-A. Methods:A retrospective cohort study was conducted to analyze the data of 685 patients with normal ovarian reserve function who underwent IVF/ICSI after ovulation induction with antagonist flexible regimen between January 2016 and June 2021 at the Reproductive Medicine Center of the Third Affiliated Hospital of Zhengzhou University. The quartile method was used to group patients after the addition of the antagonist by the mean value of serum LH each time they were monitored (usually twice, depending on the rate of follicular growth and patients' need) until the day of the trigger, and were divided into group A (smaller than the 25th percentile of the mean LH level of the included population, LH<1.25 U/L, n=166), group B (in the 25th to 50th percentile of the mean LH level of the included population, 1.25 U/L≤LH<1.91 U/L, n=174), group C (in the 50th to 75th percentile of the mean LH level of the included population, 1.91 U/L≤LH<2.85 U/L, n=171), and group D (greater than the 75th percentile of the mean LH level of the included population, 2.85 U/L≤LH≤7.55 U/L, n=174). The general condition, clinical data, embryo laboratory indices, clinical outcome indices of fresh embryo transfer cycle and cumulative live birth rate were compared among the 4 groups. Results:After correcting for confounding factors by multifactorial linear regression, the number of high-quality embryos and the rate of blastocyst formation of patients in group C were significantly higher than those in group A, and the differences were statistically significant ( B=0.600, 95% CI: 0.086-1.114, P=0.022; B=0.134, 95% CI: 0.052-0.216, P=0.001). The number of high-quality embryos, the number of available embryos, and the rate of blastocyst formation of patients in group D were significantly higher than those in group A, and the differences were statistically significant ( B=0.771, 95% CI: 0.259-1.284, P=0.003; B=0.730, 95% CI: 0.205-1.255, P=0.007; B=0.085, 95% CI: 0.003-0.167, P=0.042).After multifactorial logistic regression, there was no statistically significant difference in live birth rate between group A and groups B, C and D ( P>0.05). The cumulative live birth rate of patients in group D was significantly higher than that in group A, and the difference was statistically significant ( aOR=2.439, 95% CI: 1.169-4.974, P=0.014). Conclusion:In patients with normal ovarian reserve function, a flexible protocol of antagonists was applied to promote ovulation, and the addition of antagonists had no significant effect on the clinical outcome of the fresh embryo transfer cycle in terms of mean LH levels, but the quality of the embryos was significantly reduced when the mean LH level was <1.25 U/L, and this may consequently reduce the developmental potential of the embryos and the cumulative live birth rate.

Objective:To investigate the effect of luteinizing hormone (LH) levels on the clinical outcome and cumulative live birth rate of in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) fresh embryo transfer in patients with normal ovarian reserve function after application of a flexible protocol of gonadotropin-releasing hormone antagonist (GnRH-A) to promote ovulation with the addition of GnRH-A. Methods:A retrospective cohort study was conducted to analyze the data of 685 patients with normal ovarian reserve function who underwent IVF/ICSI after ovulation induction with antagonist flexible regimen between January 2016 and June 2021 at the Reproductive Medicine Center of the Third Affiliated Hospital of Zhengzhou University. The quartile method was used to group patients after the addition of the antagonist by the mean value of serum LH each time they were monitored (usually twice, depending on the rate of follicular growth and patients' need) until the day of the trigger, and were divided into group A (smaller than the 25th percentile of the mean LH level of the included population, LH<1.25 U/L, n=166), group B (in the 25th to 50th percentile of the mean LH level of the included population, 1.25 U/L≤LH<1.91 U/L, n=174), group C (in the 50th to 75th percentile of the mean LH level of the included population, 1.91 U/L≤LH<2.85 U/L, n=171), and group D (greater than the 75th percentile of the mean LH level of the included population, 2.85 U/L≤LH≤7.55 U/L, n=174). The general condition, clinical data, embryo laboratory indices, clinical outcome indices of fresh embryo transfer cycle and cumulative live birth rate were compared among the 4 groups. Results:After correcting for confounding factors by multifactorial linear regression, the number of high-quality embryos and the rate of blastocyst formation of patients in group C were significantly higher than those in group A, and the differences were statistically significant ( B=0.600, 95% CI: 0.086-1.114, P=0.022; B=0.134, 95% CI: 0.052-0.216, P=0.001). The number of high-quality embryos, the number of available embryos, and the rate of blastocyst formation of patients in group D were significantly higher than those in group A, and the differences were statistically significant ( B=0.771, 95% CI: 0.259-1.284, P=0.003; B=0.730, 95% CI: 0.205-1.255, P=0.007; B=0.085, 95% CI: 0.003-0.167, P=0.042).After multifactorial logistic regression, there was no statistically significant difference in live birth rate between group A and groups B, C and D ( P>0.05). The cumulative live birth rate of patients in group D was significantly higher than that in group A, and the difference was statistically significant ( aOR=2.439, 95% CI: 1.169-4.974, P=0.014). Conclusion:In patients with normal ovarian reserve function, a flexible protocol of antagonists was applied to promote ovulation, and the addition of antagonists had no significant effect on the clinical outcome of the fresh embryo transfer cycle in terms of mean LH levels, but the quality of the embryos was significantly reduced when the mean LH level was <1.25 U/L, and this may consequently reduce the developmental potential of the embryos and the cumulative live birth rate.