Objective:To investigate the learning curve of laparoscopic transanal total mesorectal excision (taTME) for rectal cancer operated by one or two surgery teams.Methods:The retrospective cross-sectional study was conducted. Based on the concept of real-world research, the clinical data of 1 458 patients undergoing laparoscopic rectal cancer taTME from 44 medical centers who were registered in the Chinese taTME registry collaborative (CTRC) database from May 2010 to May 2020 were collected. The 1 458 patients were divided into cohorts with one surgery team or two surgery teams according to the operation method. Patients with one surgery team underwent taTME by transabdominal operation and then by transanal operation. Patients with two surgery teams underwent taTME by transabdominal and transanal operation simultaneously with duration of the simutaneous operation time ≥30 minutes. The entire surgical process of patients with two surgery teams is not required to be performed by two surgery teams simutaneously. The clinical data were collected from the medical centers with similar operation amount according to the operation time sequence to analyze the difference between different operation stages and explore the learning curve. The operation time was taken as the parameter to carry out cumulative sum analysis and draw the learning curve of laparoscopic rectal cancer taTME in each medical center. The clinicopathological characteristics of patients from two medical centers with the largest difference in learning curves were analyzed. Observation indicators: (1) screening results of clinical data; (2) clinical data collection of patients with one surgery team; (3) surgical situations of laparoscopic rectal cancer taTME from the one surgery team in different operation stages; (4) learning curve of the one surgery team; (5) clinical data collection of patients with two surgery teams; (6) surgical situations of laparoscopic rectal cancer taTME from the two surgery teams; (7) learning curve of the two surgery teams. The cumulative sum was calculated by the CUSUM=∑i=1nXi-U, where Xi represented the operation time of each taTME, U represented the average operation time of all cases, and n represented the operation number. Fitting process was conducted on scatter plot of learning curves. Taking the apex of learning curve as the boundary, the learning curve was divided into two stages. The abscissa corresponding to the apex of learning curve was the number of operations that needed to be performed to cross the learning curve. Measurement data with normal distribution were represented as Mean±SD. Comparison between two groups was conducted using the t test and comparison between multiple groups was conducted using the ANOVA. Measurement data with skewed distribution were represented as M( P25,P75), and comparison between groups was conducted using the Mann-Whitney U test. Comparison of ordinal data was analyzed using the rank sum test. Count data were analyzed using the chi-square test or Fisher exact probability. Results:(1) Screening results of clinical data:the clinical data of 661 patients from 7 medical centers with one surgery team and two surgery teams were collected. (2) Clinical data collection of patients with one surgery team: the clinical data of 312 patients undergoing laparoscopic rectal cancer taTME from 5 medical centers were collected including 42 cases in the number 2 medical center, 97 cases in the number 20 medical center, 82 cases in the number 33 medical center, 35 cases in the number 37 medical center and 56 cases in the number 39 medical center, respectively. (3) Surgical situations of laparoscopic rectal cancer taTME from the one surgery team in different operation stages: three medical centers including the number 2, number 37 and number 39 medical center with close operation volume provided the clinical data of cases distributed in five operation stages. Among the five operation stages, the proportion of high-quality operation of total mesorectal excision (TME) was ≥17/18, the incidence of postoperative complications was ≤13.3%(4/30) and the incidence of anastomotic leakage was ≤10.0%(3/30). There was no significant difference in the TME quality, postoperative complications or anastomotic leakage among the five operation stages ( P>0.05). There was no significant difference in the operation time among the five operation stages ( χ2=6.950, P>0.05). (4) Learning curve of the one surgery team: the number of operations corresponding to the turning point of learning curve in number 2 and number 20 medical center was 22 and 39, respectively. The number of operations corresponding to the turning points of learning curve in number 33 and number 37 medical center was 15, 66 and 10, 28, respectively. The number of operations corresponding to the turning point of learning curve in number 39 medical center was 20. The overall curve of number 20 medical center was in line with the trend of learning curve and 39 cases of operations was the minimum number needed to cross the learning curve. The biggest difference in learning curve was shown between the number 20 and number 33 medical center. Cases with the gender of male or female, age, body mass index, cases classified as stage 1, stage 2, stage 3 or stage 4 of the American Society of Anesthesiologists (ASA) Classification, cases with neoadjuvant therapy, duration of postoperative hospital stay of the number 20 medical center were 77, 20, (60±10)years, 24 kg/m 2(22 kg/m 2, 26 kg/m 2), 1, 88, 8, 0, 8, 8, 11 days (9 days, 13 days), respectively, versus 51, 31, (64±11)years, 23 kg/m 2(21 kg/m 2, 26 kg/m 2), 0, 35, 43, 1, 31, 16 days (13 day, 21 day) of number 33 medical center, showing significant differences in the above indicators between the two medical centers ( χ2 =6.442, t=-2.265, Z=-2.032, -6.870, χ2 =22.120, Z=-8.408, P<0.05). (5) Clinical data collection of the two surgery teams: the clinical data of 259 patients undergoing laparoscopic rectal cancer taTME from 5 medical centers were collected, including 46 cases in the number 2 medical center, 47 cases in the number 8 medical center, 78 cases in the number 18 medical center, 43 cases in the number 33 medical center and 45 cases in the number 44 medical center, respectively. (6) Surgical situations of laparoscopic rectal cancer taTME from the two surgery teams: four medical centers including the number 2, number 8, number 33 and number 44 medical center with close operation volume provided the clinical data of cases distributed in four operation stages. Among the four operation stages, the proportion of high-quality operation of TME was ≥50.0%(13/26), the incidence of postoperative complications was ≤35.0%(14/40) and the incidence of anastomotic leakage was ≤22.5%(9/40). There was no significant difference in the TME quality, postoperative complications or operation time among the four operation stages ( χ2 =3.252, 4.733, 8.848, P>0.05). There was a significant difference in the incidence of anastomotic leakage among the four operation stages ( P<0.05). (7) Learning curve of the two surgery teams: the number of operations corresponding to the turning point of learning curve in number 2 and number 8 medical center was 28 and 16, respectively. The number of operations corresponding to the turning points of learning curve in number 18, number 33 and number 44 medical center was 12 and 58, 10 and 36, 14 and 36, respectively. The overall curve of number 2 medical center was in line with the trend of learning curve and 28 cases of operations was the minimum number needed to cross the learning curve. The biggest difference in learning curve was shown between the number 2 and number 33 medical center. The age and cases with tumor in stage T0 and (or) Tis, stage T1, stage T2, stage T3 or stage T4 of the T staging of the number 2 and number 33 medical center were (60±12)years, 3, 1, 9, 11, 20 and (65±10)years, 2, 3, 22, 15, 0, respectively, showing significant differences in the above indicators between the two medical centers ( t=-2.280, Z=-4.033, P<0.05). Conclusion:Thirty-nine cases of operations was the minimum number for the one surgery team to cross the learning curve of laparoscopic rectal cancer taTME and 28 cases of operations was the minimum number for the two surgery teams to cross the learning curve of laparoscopic rectal cancer taTME.

Objective:To investigate the effect of oral contraceptive pretreatment on pregnancy outcome of modified long down-regulation protocol in in vitro fertilization and embryo transfer and intracytoplasmic sperm injection cycles. Methods:Totally 13 542 cycles were retrospectively analyzed in Reproductive Medicine Center of the 73th Group Military Hospital of PLA from January 2012 to December 2017. According to whether use oral contraceptives (OC) before down-regulation, they were divided into OC group (591 cases) and non-OC group (12 951 cases). After the variables between the two groups were balanced by the propensity score matching method, the number of oocytes obtained, number of mature oocytes, number of fertilized oocytes, number of high-quality embryos, estradiol level on human chorionic gonadotropin (hCG) trigger day, endometrial thickness on hCG trigger day, the clinical pregnancy rate and the live birth rate of the two groups were compared.Results:Before matching, the estradiol level on hCG triger day in OC group [3 118.00(2 529.00) ng/L] was lower than that in non-OC group [3 422.00(2 733.00) ng/L], with statistically significant difference ( P=0.001), there was no significant difference between OC group and non-OC group in the number of harvested oocytes and mature oocytes, fertilization number, number of viable embryos, endometrial thickness on hCG trigger day, the clinical pregnancy rate and the live birth rate. However, after adjusting for confounding factors through multi-factor logistics regression analysis, OC group was the negative factor to reduce the live birth rate compared with non-OC group (clinical pregnancy rate OR=0.83, 95% CI=0.68-1.02; live birth rate OR=0.82, with 95% CI=0.88-0.99). After matching, the clinical pregnancy rate and the live birth rate of OC group and non-OC group had no statistically significant differences (clinical pregnancy rate OR=0.94, 95% CI=0.75-1.14, P=0.59; live birth rate OR=0.91, 95% CI=0.74-1.13, P=0.38). A post-hoc power caculation demonstrated that the study sample size yielded >80% power to detect a no less than 3.7% difference between groups in the primary outcome. Conclusion:The pretreatment of oral contraceptives has no significant effect on the outcome of modified long down-regulation protocol.

Objective:To investigate the effect of oral contraceptive pretreatment on pregnancy outcome of modified long down-regulation protocol in in vitro fertilization and embryo transfer and intracytoplasmic sperm injection cycles. Methods:Totally 13 542 cycles were retrospectively analyzed in Reproductive Medicine Center of the 73th Group Military Hospital of PLA from January 2012 to December 2017. According to whether use oral contraceptives (OC) before down-regulation, they were divided into OC group (591 cases) and non-OC group (12 951 cases). After the variables between the two groups were balanced by the propensity score matching method, the number of oocytes obtained, number of mature oocytes, number of fertilized oocytes, number of high-quality embryos, estradiol level on human chorionic gonadotropin (hCG) trigger day, endometrial thickness on hCG trigger day, the clinical pregnancy rate and the live birth rate of the two groups were compared.Results:Before matching, the estradiol level on hCG triger day in OC group [3 118.00(2 529.00) ng/L] was lower than that in non-OC group [3 422.00(2 733.00) ng/L], with statistically significant difference ( P=0.001), there was no significant difference between OC group and non-OC group in the number of harvested oocytes and mature oocytes, fertilization number, number of viable embryos, endometrial thickness on hCG trigger day, the clinical pregnancy rate and the live birth rate. However, after adjusting for confounding factors through multi-factor logistics regression analysis, OC group was the negative factor to reduce the live birth rate compared with non-OC group (clinical pregnancy rate OR=0.83, 95% CI=0.68-1.02; live birth rate OR=0.82, with 95% CI=0.88-0.99). After matching, the clinical pregnancy rate and the live birth rate of OC group and non-OC group had no statistically significant differences (clinical pregnancy rate OR=0.94, 95% CI=0.75-1.14, P=0.59; live birth rate OR=0.91, 95% CI=0.74-1.13, P=0.38). A post-hoc power caculation demonstrated that the study sample size yielded >80% power to detect a no less than 3.7% difference between groups in the primary outcome. Conclusion:The pretreatment of oral contraceptives has no significant effect on the outcome of modified long down-regulation protocol.

Objective:To compare the effects of pituitary down-regulation in combination with hormone replacement therapy endometrial preparation protocol and conventional hormone replacement therapy endometrial preparation protocol on outcomes of frozen-thawed embryo transfer (FET) in patients without endometriosis.Methods:The retrospective study included 3562 FET cycles was carried out between January 2012 and December 2017 in Reproductive Medicine Center, 73rd Group Army Hospital of PLA. Among them, 807 cycles were under hormone replacement therapy in combination with pituitary down-regulation with gonadotropin-releasing hormone agonist (GnRH-a) (experimental group) and 2755 cycles were under conventional hormone replacement therapy (control group). Association between endometrial preparation protocols and pregnancy and live birth was analyzed with multivariate logistic regression.Results:In experimental group, the maternal age [(31.19±4.58) years old] and endometrial thickness [(8.95±1.75) mm] were higher than those in control group [(29.84±4.23) years old, (8.46±1.41) mm, all P<0.001], the proportion of cycles with at least one good-quality embryo transferred (9.2%) was lower than that in control group (19.5%, P<0.001). The pregnancy rate (55.3%) was higher than that in control group (51.3%, P=0.045). The live birth rate showed an increasing trend in experimental group in comparison with that in control group, but the difference was not statistically significant ( P=0.78). In multivariate logistic regression with adjustment of confounding factors including maternal age, duration of infertility, endometrial thickness on the day of endometrial transition, number of embryos transferred, blastocyst transfer and at least one good-quality embryo transferred, the odds ratio ( OR) for pregnancy comparing experimental group with control group was 1.209 (95% CI=1.023-1.429) and OR for live birth was 1.246 (95% CI=1.053-1.474). Conclusion:Pituitary down-regulation in combination with hormone replacement therapy as endometrial preparation protocol for FET may achieve higher pregnancy rate and live birth rate than conventional hormone replacement protocol.

Objective:To compare the effects of pituitary down-regulation in combination with hormone replacement therapy endometrial preparation protocol and conventional hormone replacement therapy endometrial preparation protocol on outcomes of frozen-thawed embryo transfer (FET) in patients without endometriosis.Methods:The retrospective study included 3562 FET cycles was carried out between January 2012 and December 2017 in Reproductive Medicine Center, 73rd Group Army Hospital of PLA. Among them, 807 cycles were under hormone replacement therapy in combination with pituitary down-regulation with gonadotropin-releasing hormone agonist (GnRH-a) (experimental group) and 2755 cycles were under conventional hormone replacement therapy (control group). Association between endometrial preparation protocols and pregnancy and live birth was analyzed with multivariate logistic regression.Results:In experimental group, the maternal age [(31.19±4.58) years old] and endometrial thickness [(8.95±1.75) mm] were higher than those in control group [(29.84±4.23) years old, (8.46±1.41) mm, all P<0.001], the proportion of cycles with at least one good-quality embryo transferred (9.2%) was lower than that in control group (19.5%, P<0.001). The pregnancy rate (55.3%) was higher than that in control group (51.3%, P=0.045). The live birth rate showed an increasing trend in experimental group in comparison with that in control group, but the difference was not statistically significant ( P=0.78). In multivariate logistic regression with adjustment of confounding factors including maternal age, duration of infertility, endometrial thickness on the day of endometrial transition, number of embryos transferred, blastocyst transfer and at least one good-quality embryo transferred, the odds ratio ( OR) for pregnancy comparing experimental group with control group was 1.209 (95% CI=1.023-1.429) and OR for live birth was 1.246 (95% CI=1.053-1.474). Conclusion:Pituitary down-regulation in combination with hormone replacement therapy as endometrial preparation protocol for FET may achieve higher pregnancy rate and live birth rate than conventional hormone replacement protocol.