endometriosis is one of the most common benign diseases affecting quality of life and fertility of women .
endometriosis is diagnosed by visual inspection of the pelvis during laparoscopy and positive histology confirms the diagnosis , but negative histology does not exclude it .
the most important one is regurgitation of menstrual blood , but cytokines play a critical role in facilitation of the implantation of ectopic endometrial tissues .
numerous data indicate that eutopic endometrial glandular and stromal cells may be functioning differently in women with endometriosis compared to normal endometrium in disease - free women .
expression of importin13 , a possible marker for endometrial stem cells , compared to secretory endometrium , might support the hypothesis that this disease originates from stem cells .
the most prominent symptoms of endometriosis are dyspareunia , dysmenorrhea , pelvic pain , and infertility .
some medical treatments have been suggested for endometriosis , including oral contraceptive pills , medroxy progesterone acetate , and gonadotropin - releasing hormone agonists ( gnrha ) . in some studies statins were effective in prevention of endometriotic cells proliferation in vitro .
statins are potent inhibitors of cholesterol biosynthesis to reduce serum cholesterol in patients with hyperlipidemia .
statins act by inhibiting 3-hydroxy-3-methyl glutaryl coenzyme a ( hmg - coa ) reductase to block the conversion of hmg - coa to l - mevalonate , a rate - limiting step in cholesterol synthesis .
statins were effective in inhibiting the mechanisms of cell proliferation and angiogenesis in experimental models for the development of endometriosis - like tissue [ 57 ] . in 1 study using a nude mouse model ,
simvastatin induced a dose - dependent decrease of the number and size of endometrial implants in mice . at the highest dose of simvastatin ,
the number of endometrial implants decreased by 87% and the volume by 98% . in another study on endometriotic cyst walls and endometrial biopsy in vitro ,
atorvastatin treatment had no effect on 17e2 levels in endometriotic stromal cell culture supernatant , and concluded that atorvastatin can be used as a treatment for endometriosis in humans .
different studies have suggested that the role of statins in inhibition of aromatase activity may represent a new therapeutic option for endometriosis .
after approval by ethics committee of tehran university of medical sciences ( tums ) and after counseling with patients with pelvic endometriosis , we compared the clinical symptoms of patients after prescription of gnrha with simvastatin .
this study was conducted as a prospective , randomized , controlled trial to compare the effectiveness of simvastatin with that of gnrha treatment , after surgery for endometriosis , on pain due to endometriosis . in our gynecology ward ,
all the patients with the laparoscopic diagnosis of pelvic endometriosis were included in the study .
, the surgeons tried to excise or ablate all the endometriotic implants and performed adhesiolysis .
the cause of laparoscopy and the severity of dyspareunia , dysmenorrhea , and pelvic pain were estimated by use of the visual analogue scale test ( vas test ) , with a score of 0 being no pain and 10 being the most severe pain ever experienced .
after the operation , the severity of endometriosis was entered into the data collection form as revised according to the american society for reproductive medicine classification for endometriosis .
the staging was done intraoperatively by the 2 surgeons who were involved in the operations . following ethics committee approval and obtaining informed consent in cases of simvastatin prescription , we prescribed simvastatin ( film - coated tablet simvahexal , 20 mg daily for 4 months ) or gnrha ( decapeptyl 3.75 mg i m each 28 day period for 4 doses ) at the time of discharge .
the patients were randomly assigned to either the simvastatin or decapeptyl group ( assigned to each group alternately in order of admission ) . although the patient selection was random , in patients who wanted to become pregnant immediately , we had the obligation to prescribe simvastatin rather than gnrha .
each group had 30 patients and we tried to match the two groups for age , the severity of endometriosis and severity of endometriotic pain .
we analyzed the data by spss 13 , using the ks test ( one - sample kolmogorov - smirnov test ) for normality of data distribution , levene s test for equality of variances , and independent samples t - test for equality of means for comparing quantitative normal data between the 2 groups , paired sample t - tests for comparing quantitative normal data between before and after treatment in each group and pearson chi - square test for matching and comparing categorical variables between the 2 groups . according to the ks test ,
we compared the non - normal quantitative data by mann - whitney u nonparametric test between the 2 groups and wilcoxon signed ranks test for comparing before and after treatment data in each group .
in these 60 patients , 40 had endometrioma of ovary ; the size of endometrioma was most often 310 centimeters ( n=37 ) . in this study , marital status of the 2 patient groups 
the simvastatin group ( s ) and the gnrha group ( g )  was matched ( p=0.793 ) , but the difference for presence of endometrioma between the two groups was significant ( p=0.045 ) , ( table 1 ) .
the major reasons for laparoscopy in the simvastatin group were infertility ( 40.0% ) and ovarian cyst ( 33.3% ) and ovarian cyst ( 40.0% ) and dysmenorrhea ( 30.0% ) in the gnrha group ( table 2 ) .
severity of endometriosis in the 2 patient groups was not significantly different ( p=0.253 ) ( table 3 ) .
the severity of dyspareunia , dysmenorrhea , and pelvic pain before and after treatment were not significantly different between the 2 groups ( table 4 ) .
however , after treatment , the severity of dyspareunia , dysmenorrhea , and pelvic pain in the 2 groups was significantly reduced and the difference between before and after treatment in 3 parameters in each group was significant ( table 5 ) .
none of the patients showed adverse effects of simvastatin and all continued medical treatment for 4 months .
the major finding of this prospective , randomized , double - blind trial of simvastatin versus decapeptyl in the treatment of endometriotic pains was that after ablative surgery , prescription of simvastatin or decapeptyl resulted in no significant difference in outcome .
laparoscopy is recognized as the first option for diagnosis and treatment of endometriosis , but the rate of pain recurrence after conservative surgery is high .
gnrh agonists have long been used successfully in the treatment of endometriosis [ 1,1115 ] , but because of their adverse effects ( loss of bone minerals and vasomotor symptoms ) , physicians need better choices .
statins , inhibitors of 3-hydroxy-3methylglutaryl - coenzyme a reductase ( hmgcr ) , have been shown to decrease proliferation of several mesenchymal tissues .
actions of statins may be related to decrease in availability of cholesterol , as well as intermediate metabolites of mevalonate pathway downstream of hmgcr .
this could be important in non - hormonal and non - surgical treatment of endometriosis .
proliferation of endometrial stromal cells has been inhibited with simvastatin in endometrial tissue obtained from 4 women with endometriosis .
therefore , it is suggested that simvastatin could potentially be a therapeutic agent for treatment of endometriosis .
the in vitro studies demonstrated that simvastatin induced a concentration - dependent inhibition of human endometrial stromal cell proliferation , evidenced by reduced dna synthesis and a decrease in number of viable cells .
it has also shown that simvastatin inhibits the proliferation of stromal cells derived from human endometriotic implants in ovaries .
simvastatin reduced both the number and volume of endometriotic lesions in nude mice in a dose - dependent manner .
about 85% of the mice in the control group developed lesions , whereas 58% of the mice receiving low - dose simvastatin and only 17% of those given high - dose simvastatin had lesions .
these findings suggested that the use of statins for treatment of endometriosis can be effective . in our study , after conservative surgical treatment , the result of prescription of simvastatin ( 20 mg daily for 4 months ) was similar to decapeptyl ( 3.75 mg i m for 4 doses ) in control of endometriotic pain .
the sample size was small and the study must be repeated with larger sample sizes and with other doses of simvastatin . in addition , none of the patients accepted second - look laparoscopy to evaluate size and number of endometriotic lesions after medical treatment .
finally , our study lacked a third group without medical treatment after conservative surgical treatment .
the important aspect of this study is that it is the first to evaluate use of simvastatin to relieve endometriotic pains .
further investigations without the limitations of the present study should provide more precise assessment of the effects of simvastatin on endometriotic lesions .
the study must be repeated with larger sample sizes and with other doses of simvastatin . in addition , none of the patients accepted second - look laparoscopy to evaluate size and number of endometriotic lesions after medical treatment .
finally , our study lacked a third group without medical treatment after conservative surgical treatment .
the important aspect of this study is that it is the first to evaluate use of simvastatin to relieve endometriotic pains .
further investigations without the limitations of the present study should provide more precise assessment of the effects of simvastatin on endometriotic lesions .
gnrha is one of the most accepted medical treatments of endometriosis , but the role of statins in endometriosis had been assessed only in vitro or in animal models .
our study assessed the effect of simvastatin on symptoms of endometriosis and found that it is comparable with decapeptyl .
 backgroundto compare efficacy of simvastatin with gnrha ( decapeptyl 3.75 mg ) on endometriosis - related pains following surgery for endometriosis.material/methodssixty women with pelvic endometriosis , after laparoscopic diagnosis and conservative laparoscopic surgery , were treated with either simvastatin ( n=30 ) for 16 weeks or decapeptyl ( n=30 ) every 4 weeks for 4 doses.resultsusing vas , the score of dyspareunia , dysmenorrhea , and pelvic pain 6 months after laparoscopic surgery declined significantly in both groups ( p=0.001 ) , but the difference between results of the 2 groups was not significant ( p>0.05).conclusionsboth treatment modalities showed comparable effectiveness in the treatment of pains related to endometriosis . 
Background
Material and Methods
Results
Discussion
Limitations of study
Conclusions