endometrial cancer ( ec ) is one of the most common gynecologic malignancies , occupying the sixth place in malignant tumor throughout the world with an increasing trend .
the initial treatment of ec is comprehensive staging surgery , which consists of total hysterectomy , bilateral salpingo - oophorectomy , pelvic and para - aortic lymphadenectomy and peritoneal cytology .
laparotomy is the traditional approach , but laparoscopic surgery is widely proposed recent years since it was first reported using for the treatment of ec in 1992 by childers and surwit . in lots of retrospective and prospective studies ,
laparoscopy has been showed with many advantages compared to laparotomy , such as smaller incision , less pain , and faster recovery .
it seems that laparoscopic surgery for ec also has similar recurrence rate and survival outcome with laparotomy procedure .
however , most of these studies have focused on patients with early stage or low - risk disease and few specifically on patients with advanced stage or high risk .
what 's more , data of long - term survival outcomes about laparoscopic surgery remain limited .
willis et al have published an article about laparoscopic hysterectomy in a high - risk series of patients with ec , showed that laparoscopy provide all the benefits inherent in minimal access surgery with no compromise in terms of outcomes , but there was no laparotomy data as control .
therefore , to compare the long - term safety and efficacy between laparoscopic surgery and laparotomy in patients with high - risk ec , we conducted a retrospective analysis based on our decade of clinical data using propensity score matching ( psm ) in this research .
a total of about 400 medical case notes of patients with histologically confirmed ec who has been received surgical treatment in beijing chao - yang hospital affiliated capital medical university from 2000 to april 2014 were reviewed .
we selected subjects according to the following criteria : high - risk ( grade 2 , histologic nonendometrioid , myometrial invasion 1/2 , positive pelvic or para - aortic nodes or stages ii 
iv ) patients who had undergone comprehensive surgical staging in the form of peritoneal cytology , total hysterectomy , bilateral salpingo - oophorectomy , pelvic lymphadenectomy and para - aortic lymphadenectomy or sampling , + / cytoreductive surgery by the same experienced surgical team via laparotomy ( total abdominal hysterectomy , tah ) or laparoscopy ( total laparoscopic hysterectomy , tlh ) .
para - aortic lymphadenectomy was performed when para - aortic lymph nodes sampled positive and nonendometrioid carcinomas .
patients who were enrolled ( excepted staged i ag2 with histologic endometrioid ) received postoperative adjuvant therapy including 3 to 6 cycles of chemotherapy ( paclitaxel , 175  mg / m  +  carboplatin , area under the concentration 
time curve [ auc ] 5 or adriamycin , 45  mg / m  +  cisplatin , 50  mg / m  +  paclitaxel , 160  mg / m ) and vaginal cuff brachytherapy or pelvic irradiation ( 45  gy over 5 weeks ) .
patients had antibiotic prophylaxis ( cephalosporins or quinolones ) half an hour before operation and venous thrombosis prophylaxis after operation by using molecular weight enoxaparin ( 0.4  ml every day for 45 days ) and lower extremity sequential compression device or graduated compression stocking .
patients associated with severe cardiopulmonary disease ( myocardial infarction , heart failure , or cerebral infarction ) , other malignancies or a bulky uterus 12 weeks of gestation were excluded . because our data source was case notes and the missing data were few , we deleted the individuals with missing data .
the collected data of patients included age , body mass index ( bmi ) , the scope of operation , operating time , blood loss , intraoperative and postoperative complications , first flatus time , postoperative hospital stay , surgical stage , histologic type and grade , number of lymph nodes dissection , and clinical outcome .
the staging of patients was done according to the international federation of gynecology and obstetrics ( figo ) 2009 staging classification .
intraoperative complications included injuries to bladder , ureter , intestine or large vessels , bleeding requiring blood transfusion , conversion from laparoscopy to laparotomy and transferred to intensive care unit ( icu ) for any unintended reasons .
postoperative complications included fever ( > 38c ) after 24  hours postoperatively , wound infection or dehiscence , deep - vein thrombosis ( dvt ) , and pulmonary embolism ( pe ) within 30 days after operation .
the overall survival ( os ) was defined as the period from the date of surgery to death or the date of last contact for living people .
follow - up is completed by telephone , e - mail , or outpatient service .
all procedures were approved by the ethics committee for human experiments of the capital medical university . because parts of the baseline characteristics were statistical different between patients received laparoscopic surgery and laparotomy
eight covariates entered in the propensity model , including age , bmi , the scope of operation , myometrial invasion , pathologic type and grade , lymph node metastasis , and surgical stage .
propensity scores were calculated using a nonparsimonious multivariable logistic regression model to estimate the conditional probability of a patient receiving a surgery approach .
then a 1:1 match between the laparoscopy and laparotomy groups was performed by using the nearest available neighbor matching . after matching ,
data of patient baseline characteristics , operation outcome and incidence of intraoperative and postoperative complication were compared using t test , chi - square test , or fisher exact test .
survival data were estimated using kaplan  meier curves and compared between groups by log - rank statistics . the 5- and 10-year survival rate and os were reported .
all of the statistical analysis was completed by spss 19.0 ( spss version 19.0 ; spss , inc . , chicago , il ) . statistical significance was defined as p  <  0.05 .
three hundred eighty - two case notes were reviewed including 255 patients with high - risk ec . among these 225 patients ,
31 individuals with severe cardiopulmonary disease , other malignancies or uterus 12 weeks of gestation were excluded ; 4 individuals with missing surgical or pathological data were deleted .
finally , a total of 220 patients with high - risk ec met the study criteria , 107 were treated by laparotomy and 113 by laparoscopy .
table 1 provides details of patient characteristics across the laparotomy and laparoscopy group pre- and postpropensity score matching . before matching
, significant differences were not found in age , myometrial invasion , pathological type , and grade and lymph node metastasis between 2 groups but in bmi , scope of operation , and figo stage which could be the confounding factors . after matching , 81 pairs of patients were matched successfully . in the matched cohorts
baseline patient characteristics pre- and postpropensity score matching the mean operative time was similar between 2 groups , 253  minutes in laparoscopy group and 258  minutes in laparotomy group .
the mean blood loss were significant less in laparoscopy group ( 107  ml ) than laparotomy group ( 414  ml ) ( p  <  0.01 ) .
the laparoscopy cohort also has significant shorter first flatus time ( 2.0 days vs. 2.4 days , p  <  0.01 ) and postoperative hospital stay ( 14.7 days vs. 17.7 days , p  =  0.02 ) than laparotomy which meant that patients received laparoscopic surgery had more rapid recovery than that received laparotomy .
the mean numbers of pelvic lymph nodes dissected by laparoscopy were 16.6 compared 21.9 by laparotomy with significant difference ( p  <  0.01 ) .
however , the mean numbers of para - aortic lymph nodes were comparable between 2 groups ( p  =  0.11 ) ( table 2 ) .
comparison of operation outcome intraoperative complications were significant different between the 2 groups ( 6.2% for laparoscopy and 25.9% for laparotomy , p  <  0.01 ) .
the patients received transfusion during surgery in laparotomy group was statistically more than that in laparoscopy ( p  <  0.01 ) . for the incidence of transferred to icu on account of poor cardiopulmonary resuscitation , it was also statistically higher in patients treated by laparotomy than by laparoscopy . moreover , no injury to bladder , ureter , or large vessels occurred in both 2 groups , only 1 patient in laparotomy group had the intestine injury because of heavy pelvic adhesion that had been received intestinal repair .
there was no significant difference in postoperative complications between the 2 groups ( 19.8% for laparoscopy and 29.6% for laparotomy , p  =  0.14 ) .
dvt occurred more often in laparotomy patients than laparoscopy patients , 14.8% versus 3.7% ( p  =  0.01 ) .
six patients developed pe in laparotomy group compared 1 in laparoscopy with no statistically difference ( table 3 ) .
comparison of intraoperative and postoperative complications clinical outcome of 2 groups was shown in table 4 .
the median follow - up was 45 months ( rang 5176 ) . during the follow - up time
, there were 16 ( 9.9% ) recurrences which were similar between the 2 treatment cohorts , 7 ( 8.6% ) were observed in laparotomy group at peritoneal , liver , lung , vaginal , and abdominal incision versus 9 ( 11.1% ) in laparoscopy group at peritoneal , liver , lung , and vaginal .
twenty patients died , 11 in the laparotomy group and 9 in the laparoscopy group .
the kaplan  meier estimate for survival rate in laparotomy and laparoscopy at 5 years was 89.2% , 85.3% and at 10 years was 75.8% , 85.3% , respectively .
no statistically significant difference was found between the 2 groups when os was compared ( p  =  0.97 ) ( figure 1 ) .
it showed that no significant difference between laparotomy and laparoscopy cohorts ( 75.8% vs. 85.3% , p  =  0.97 ) .
three hundred eighty - two case notes were reviewed including 255 patients with high - risk ec . among these 225 patients ,
31 individuals with severe cardiopulmonary disease , other malignancies or uterus 12 weeks of gestation were excluded ; 4 individuals with missing surgical or pathological data were deleted .
finally , a total of 220 patients with high - risk ec met the study criteria , 107 were treated by laparotomy and 113 by laparoscopy .
table 1 provides details of patient characteristics across the laparotomy and laparoscopy group pre- and postpropensity score matching . before matching
, significant differences were not found in age , myometrial invasion , pathological type , and grade and lymph node metastasis between 2 groups but in bmi , scope of operation , and figo stage which could be the confounding factors . after matching , 81 pairs of patients were matched successfully . in the matched cohorts
the mean operative time was similar between 2 groups , 253  minutes in laparoscopy group and 258  minutes in laparotomy group .
the mean blood loss were significant less in laparoscopy group ( 107  ml ) than laparotomy group ( 414  ml ) ( p  <  0.01 ) .
the laparoscopy cohort also has significant shorter first flatus time ( 2.0 days vs. 2.4 days , p  <  0.01 ) and postoperative hospital stay ( 14.7 days vs. 17.7 days , p  =  0.02 ) than laparotomy which meant that patients received laparoscopic surgery had more rapid recovery than that received laparotomy .
the mean numbers of pelvic lymph nodes dissected by laparoscopy were 16.6 compared 21.9 by laparotomy with significant difference ( p  <  0.01 ) .
however , the mean numbers of para - aortic lymph nodes were comparable between 2 groups ( p  =  0.11 ) ( table 2 ) .
intraoperative complications were significant different between the 2 groups ( 6.2% for laparoscopy and 25.9% for laparotomy , p  <  0.01 ) . none of the laparoscopic cases was converted into open procedures .
the patients received transfusion during surgery in laparotomy group was statistically more than that in laparoscopy ( p  <  0.01 ) . for the incidence of transferred to icu on account of poor cardiopulmonary resuscitation
, it was also statistically higher in patients treated by laparotomy than by laparoscopy . moreover , no injury to bladder , ureter , or large vessels occurred in both 2 groups , only 1 patient in laparotomy group had the intestine injury because of heavy pelvic adhesion that had been received intestinal repair .
there was no significant difference in postoperative complications between the 2 groups ( 19.8% for laparoscopy and 29.6% for laparotomy , p  =  0.14 ) .
dvt occurred more often in laparotomy patients than laparoscopy patients , 14.8% versus 3.7% ( p  =  0.01 ) .
six patients developed pe in laparotomy group compared 1 in laparoscopy with no statistically difference ( table 3 ) .
the median follow - up was 45 months ( rang 5176 ) . during the follow - up time
, there were 16 ( 9.9% ) recurrences which were similar between the 2 treatment cohorts , 7 ( 8.6% ) were observed in laparotomy group at peritoneal , liver , lung , vaginal , and abdominal incision versus 9 ( 11.1% ) in laparoscopy group at peritoneal , liver , lung , and vaginal .
twenty patients died , 11 in the laparotomy group and 9 in the laparoscopy group .
the kaplan  meier estimate for survival rate in laparotomy and laparoscopy at 5 years was 89.2% , 85.3% and at 10 years was 75.8% , 85.3% , respectively .
no statistically significant difference was found between the 2 groups when os was compared ( p  =  0.97 ) ( figure 1 ) .
it showed that no significant difference between laparotomy and laparoscopy cohorts ( 75.8% vs. 85.3% , p  =  0.97 ) .
for accurately estimating the effect of intervention , randomized controlled trial ( rct ) is considered the optimal approach but often limited by ethic and other problems .
psm can eliminate the imbalance between groups and reduce the effects of confounding to achieve a random effect in observational studies . in the present study ,
the patient baseline characteristics of laparotomy and laparoscopy group were adequately balanced after matching , and then , the surgery outcomes achieved comparability .
this retrospective study demonstrated that laparoscopic technique is effective and even safer compared with laparotomy for patients with high - risk ec . in 2009 , gynecologic oncology group ( gog ) compared laparoscopy and laparotomy for comprehensive surgical staging of ec in a randomized multicenter trial which involved 2616 patients and reported that laparoscopic surgery resulted in fewer complications and shorter hospital stay but longer operation time . in another large randomized trial published in 2010 , laparoscopic surgery was associated with a shorter hospital stay and less amount of blood loss , but no beneficial effect was observed in terms of major complications and operation time .
however , our data showed evidence of less blood loss , lower proportion of major complications and shorter hospital stay with laparoscopy versus laparotomy and a similar operation time .
operation time is much related to the experience of the surgical team and learning curve .
as the improvement of surgical technique , it is a trend that laparoscopic operation time becomes shorter .
moreover , our study indicated that the first flatus time was shorter in laparoscopy group than in laparotomy .
patients treated with laparoscopic surgery had smaller incision and less pain compared to those treated with laparotomy .
laparoscopy can also bring out an earlier resumption of bowel function and shorter hospital stays .
we found that the postoperative hospital stays in our data were longer than that reported in most of the previously studies and just similar to kong 's study in korea .
kong reported a mean hospitalization of 16.4 days for laparoscopy and 23.3 days for laparotomy .
but in gog study , the median hospital stays was 3 days for laparoscopy and 4 days for laparotomy .
patients in china are accustomed to a longer hospitalization , which is mainly decided by the social factors . in chinese traditional opinion , patients are willing to discharge from hospital only when they have complete recovery ( after removing drainage tube and urinary catheter or taking out stitches ) , what 's more , they need not worry about the medical expense because of the coverage of insurance .
so , some patients even have been in hospital until the end of the first chemotherapy . in the present study ,
intraoperative complications were significantly lower in the laparoscopy group and no injuries to bladder , ureter , or large vessels occurred .
the incidence of major complications can be highly reduced when the procedure was performed by experience surgeon .
however , it seems that laparoscopy had no benefit in the incidence of postoperative complications .
but we found dvt occurred significantly often in patients treated by laparotomy than those treated by laparoscopy . in gog study , there was no significant difference in incidence of venous thromboembolism ( vte ) and pe between different approaches .
in contrast , fader 's study showed that the laparoscopy cohort had significantly fewer episodes of vte .
lots of studies indicate that the combination of underlying malignancy and pelvic surgery is the risk for developing a vte . in a japanese large research about risk factors for vte , the age ( 50 or 55 years ) , a diagnosis of cancer , operating time ( 4  hours ) , blood loss ( 1000  ml ) , and blood transfusion ( 2000  ml ) were reported significantly related to postoperative vte .
it may account for the difference of dvt incidence between the 2 groups that laparotomy had longer operating time and more blood loss in our study . what 's more , trendelenburg position during laparoscopic surgery may play a role in preventing vte .
most of the previous studies demonstrate that the pelvic or para - aotic lymph nodes count removed by laparoscopy approach were similar to those dissected by laparotomy .
laparoscopy has been proven to be even more efficient in lymphadenectomy because of its clearer vision .
however , obermair and kalogiannidis reported lower number of lymph node dissections in the laparoscopy group . in the present study , the mean number of dissected para - aotic lymph nodes was comparable between the 2 groups , but the pelvic lymph nodes were significant fewer in laparoscopy cohort than laparotomy .
two large rcts reported by benedett and kitchener showed no evidence that lymphadenectomy could decrease the risk of recurrence or mortality rate in patients with early ec .
conversely , another retrospective research gave a result that lymphadenectomy improved the survival of patients with high - risk ec and stage i b to stage iv .
moreover , an article published in lancet in 2010 reported that para - aotic had a significantly benefit in terms of os for patients with ec at mediate or high risk .
it seems that the difference of pelvic lymph nodes count between the laparoscopy and laparotomy groups had not influenced the os in our study .
lots of previous studies have proven that laparoscopy surgery was similar to laparotomy in short - term survival . a meta - analysis reported in 2012
based on 8 rcts showed that there was no significant difference in disease - free survival , cancer - related survival , or os .
cho et al reported a similar 5-year os and progression - free survival between laparoscopy and laparotomy groups based on 10-year experience . in 2012 , the gog published the survival data of their large rct in 2009 that the 5-year os was almost identical in both laparoscopy and laparotomy cohorts at 89.8% . between 2000 and 2010
, we conducted a randomized trial and reported that the 5-year os rates were 91% of laparotomy and 96% of laparoscopy with no significantly difference . in another retrospective study focus on high - grade ec in 2012 , progression - free and os were not significantly different between the surgical cohorts at 44-month median follow - up . in the present study , parts of patients were follow - up more than 10 years . with a median follow - up time of 45 months ,
the 5- and 10-year survival rate for the laparotomy were 89.2% and 75.8% compared with 85.3% and 85.3% for the laparoscopy .
there was no significant difference in os between 2 cohorts and also the recurrence rate .
although the patients enrolled were not assigned to different approaches randomly which was a limitation of our study , we performed a psm and successfully to control a certain confounding factors yet .
when randomized trial was limited by the objective conditions , psm might be a feasible alternative to reduce selection bias . in conclusion
, it seems that laparoscopic surgery is as effective as laparotomy in the long term and can be safely carried out in patients with high - risk ec for surgery treatment .
furthermore , other long - term follow - up data on high - risk ec of randomized trials is still needed to confirm these results .
 abstractthe aim of this study was to compare the long - term safety and efficacy of laparoscopic surgery and laparotomy for high - risk endometrial cancer ( ec).a retrospective analysis based on our decade of clinical data of patients with high - risk ec who were comprehensively surgically staged by laparotomy or laparoscopy was performed . 
 the surgical outcomes were compared between different approaches using propensity score matching ( psm).eighty - one pairs of patients from the initial 220 enrolled ones were matched by psm . 
 the mean operative time is similar between laparotomy and laparoscopy groups ( 258  minutes vs. 253  minutes ) . 
 the laparoscopy cohort has less blood loss ( 107  ml vs.414  ml , p  <  0.01 ) , shorter hospital stay ( 14.7 days vs. 17.7 days , p  =  0.02 ) and significant fewer intraoperative complications ( 6.2% vs. 25.9% , p  <  0.01 ) . 
 the pelvic lymph nodes dissected by laparoscopy ( 16.4 ) were significant less than that dissected by laparotomy ( 21.9 ) . 
 the 5- and 10-year survival rate for laparotomy were 89.2% and 75.8% compared with 85.3% and 85.3% for the laparoscopy . 
 there was no significant difference in overall survival ( p  =  0.97).laparoscopy is as effective as laparotomy in the long term and can be safely carried out in patients with high - risk ec for surgery treatment . 
INTRODUCTION
MATERIALS AND METHODS
RESULTS
Baseline Characteristics
Operation Outcome
Intraoperative and Postoperative Complication
Clinical Outcome
DISCUSSION