metastases to the adrenal glands represent the second most common type of adrenal mass after adrenal adenomas . lung , breast , stomach , and kidney cancers and melanomas and lymphomas most commonly metastasize to the adrenal glands . management strategy of adrenal metastases ( am ) varies depending on the different clinical situation and can include close observation , chemotherapy , local ablative therapy , radiotherapy , or surgical resection [ 36 ] . several studies have confirmed prolonged survival after an adrenal metastasectomy in selected patients who presented with isolated am when that is the only site of disease spread [ 710 ] . over the last few decades , laparoscopic technique radically changed adrenal surgery , making access to the adrenal glands easier and less traumatic . laparoscopic adrenalectomy ( la ) has become the gold standard for removing benign tumors of the adrenal glands because it offers lower morbidity rates , reduced postoperative pain , shorter hospital stay , perfect cosmetic results , and other benefits compared to open surgery [ 11 , 12 ] . the advantages of the transperitoneal approach include the wider working space and readily identifiable anatomic landmarks . the retroperitoneal approach was considered to be associated with more direct access to the gland , avoidance of intraperitoneal organs , avoidance of adhesions in previously operated patients , and the ability to perform bilateral adrenalectomy without repositioning . different surgical methods could be selected according to the characteristics of patients , such as tumor diameter , location , histologic type , extent of deterioration , and metastasis . advantages of laparoscopic surgery have prompted interest in expanding this method to the treatment of adrenal malignancies [ 1719 ] . long - term survival after la for isolated am was demonstrated in several reports [ 3 , 7 ] ; however , the utility of laparoscopic methods for malignancies is less certain because of concerns regarding the risk of tumor cell spillage . although controversial , la was recommended as an appropriate initial approach for isolated am in some studies , because it achieved the same level of results of tumor control and less traumas compared with open surgery [ 2123 ] . furthermore , there was no quantitative assessment concerning the association between retroperitoneal adrenalectomy and patients with am . in response , we conducted the study to evaluate the efficacy and effectiveness of endoscopic retroperitoneal adrenalectomy ( era ) for am . from june 2004 to january 2014 , 145 era were performed at vilnius university hospital santariskiu klinikos . the diagnosis of am from primary tumor was suspected in any case of newly diagnosed adrenal mass , characterized by growing size on sequential imaging studies ( abdominal ultrasonosgraphy and computed tomography ( ct ) ) . all patients were evaluated with the assistance of an oncologist , with tumor - specific markers and global imaging ( ct of the chest , abdomen , and pelvis ) to search for other sites of metastatic involvement . the hormonal examination for adrenal metabolic dysfunction era was decided for patients with solitary adrenal mass inferior to 6  cm without evidence of periadrenal malignant infiltration or regional lymphadenopathy on imaging examinations , negative serologic tests for adrenal metabolic dysfunction , and patient history of malignant disease . patient demographic characteristics ( age , gender , tumor size and side , diagnosis of primary malignancy , and operative history ) are summarized in table 1 . operation reports were reviewed to obtain operative time , estimated blood loss , need for conversion to transperitoneal la or open adrenalectomy , status of resection margin , and complications . in addition , information regarding postoperative course ( postoperative hospital stay , postoperative complications , the use of adjuvant therapy within 1 year of the procedure , and survival rates ) was recorded . metastases were considered as synchronous ( < 6 months ) or metachronous ( 6 months ) depending on the interval after primary surgery . the completeness of adrenal surgery was defined in terms of r0 ( complete resection with no microscopic residual tumor ) , r1 ( complete resection with no grossly visible tumor as defined by the surgeon , but margins are microscopically positive according to the pathologist ) , r2 ( partial resection , with grossly visible tumor left behind ) , and rx ( presence of residual tumor can not be assessed ) . local recurrence was defined as radiological or biopsied confirmation of a recurrent disease in the adrenal bed . after surgery , the patients were followed up by endocrinologist and an oncologist every 6  months by physical examination and systemic ct , or sooner if they become symptomatic . overall survival was calculated from the time of adrenalectomy up to death or end of the follow - up . the posterior retroperitoneal approach was used for all era as described by walz et al . . after induction of general anesthesia , the patient is placed prone , in the jackknife position . a 2  cm sized transverse skin incision is made just below the tip of the 12th rib . the abdominal wall of the back is then opened and the retroperitoneal space exposed . a small cavity in the retroperitoneum a 10  mm trocar is then inserted through as second incision ( 4  cm removed medially from the first incision ) guided by an index finger inserted through the first incision . a third skin incision for another 10  mm trocar is made along with the lowest margin of the 11th rib 4  cm laterally from the first incision . a 10  mm blunt trocar is inserted through the first incision , and carbon dioxide is insufflated to 20  mm  hg for creation of capnoretroperitoneum . the skin sutures were secured around the gas port preventing a gas leak . after creating the retroperitoneal working space , gerota 's fascia is opened , perirenal fat is dissected , and the kidney upper pole is mobilized to expose the adrenal gland . dissection of gland starts with lower margin detachment from the upper kidney pole in a lateral to medial direction using 5  mm ultrasonic dissector . after exposing adrenal gland from surrounding tissue and medial isolation of the main suprarenal vein , the surgical specimens were always extracted in a bag and retrieved via the first trocar site . categorical variables are expressed as frequencies and percentages and continuous variables as mean and standard deviation ( sd ) . we conducted all statistical analyses using spss version 13.0 for windows ( spss inc . ) . the mean age of all patients undergoing era for am was 66.4  3.6  years . all am were unilateral ( left : five patients ; right : four patients ) . the most common primary tumor site was kidney ( 4 patients , 44% ) , followed by colon ( 2 patients , 22% ) . all patients have been operated on for primary malignancy previously . the surgical procedure consisted of contralateral era in all patients with previous kidney cancer . the mean tumor size in the preoperative radiologic imaging studies was 37  4.5  mm . five ( 56% ) patients presented with synchronous metastases , while four ( 44% ) patients presented with metachronous metastases . perioperative and postoperative data are presented in table 2 . the mean operative time and estimated blood loss during era were 132  10.4  min and 31  7  ml , respectively . one conversion to transperitoneal la occurred because of dense adhesions and difficult interpretation of anatomical structures of retroperitoneal space caused by previous left colon resection . after open insertion of the first optical trocar in to the abdominal cavity we found few intra - abdominal adhesions that do not interfere successfully to perform la . five patients ( 55,5% ) had complete macroscopic resection and negative margins ( r0 resection ) . four patients ( 44,5% ) had complete macroscopic resection too but margins on pathology examination were not assessed because the surgical specimen was morcellated with forceps in a bag to make it easier to remove via trocar incision ( rx resection ) . in all cases , pathological examinations revealed the diagnosis of metastasis related to primary malignancies . the mean specimen weight in the pathologic studies was 45.9  11.4  g. the mean observed follow - up ( fu ) was 20 ( range : 242 ) months . the median overall survival was 11 months ( range : 242  months , figure 1 ) . survival at 1 year was 50% ( 95% ci , 1577 ; figure 1 ) and at 3 years , 25% ( 95% ci , 164 ) . the difference between the median survival for patients with standard duration and long duration of surgery was significant ( p = 0,024 ) ( figure 2 ) . in patients with standard duration of surgery ( 120  min ) median survival was 38 months ( 95% ci , 23 , 2544 , 75 ) compared with long duration of surgery ( > 120  min ) where median survival was 6 months ( 95% ci , 4 , 410 , 93 ) . the differences between the median survival for patients with small and big tumors ( p = 0,180 ; figure 3 ) , with different origin of metastases ( p = 0,103 ; figure 4 ) and with synchronous and metachronous metastases ( p = 0,711 ; figure 5 ) , were not significant . at the end of the study , 4 ( 45% ) patients were alive with a mean fu of 20 months . three patients were alive without evidence of disease 42 , 26 , and 24 months after era . the longest survival ( 42  months ) was observed in a female patient with metachronous am and primary malignancy of kidney . causes of death in the 4 patients who did not survive 1 year were progression of disease in 3 ( 75% ) and causes unrelated to the malignant disease in 1 ( 25% ) . no local tumor recurrence or port - site metastases the number of patients successfully undergoing la reported by most authors is small , and many studies have failed to stratify patients according to whether they had primary adrenal cancer or metastatic disease [ 9 , 18 , 19 , 27 ] . metastasis to the adrenal gland should be suspected in patients with adrenal incidentaloma and a history of cancers most frequently metastasizing to the lung , breast , kidney , or colon . many reports in the literature have demonstrated success of la in cases with solitary metastases , achieving a very low incidence of local recurrences or peritoneal dissemination [ 17 , 29 , 30 ] . the main aspect to consider for the success of laparoscopy is a small size of the adrenal tumor . in present study , the mean diameter of such metastases was 3.7  cm and we performed era in all cases . the main concern of the surgical procedure is to make the patient tumor - free and it is therefore of a great importance to follow oncological principles . we recommend excision of any adrenal metastases without touching the tumor or the gland ; the surgeon should start the procedure from the perirenal fat tissue , to avoid the risk of tumor spillage or incomplete resection . we evaluated the safety and efficiency of era for am and found a trend toward decreased operation time ( 132  min versus 144  min ) , blood loss ( 31  ml versus 130  ml ) , and complication rate ( 0% versus 8,35% ) in our study group compared to results of la for metastasis in other published series summarized in table 3 [ 7 , 20 , 23 , 28 , 3038 ] . reported that despite the narrower working space and unfamiliar retroperitoneal landmarks , the era was associated with decreased operative time and rapid patient recovery . the local recurrence rate was satisfied , which may be attributed to the en bloc resection of metastases in era . the mean postoperative hospital stay 3,7 days was similar like that in other studies [ 9 , 22 , 23 ] . approving that era for am is superior to la based on our data is still too early due to lack of a control group and low number of cases in our series . despite potential improved surgical outcomes , the oncological outcomes of laparoscopic approach have remained in question with concerns about inadequate oncological resection . in the largest series to date of patients undergoing adrenal metastasectomy , strong et al . when they compared the survival rate between the open and laparoscopic groups , they found no differences , suggesting equal oncological outcomes between the two approaches . moreno et al .   also reported that the median overall survival was 29 months and 5-year survival rate was 35% after adrenalectomy for solid tumor . in our study , the median overall survival was 11 months and 1 and 3 years survival rates were 50% and 25% . the longest survival was found in patients with metastases for renal carcinoma and colorectal cancer . even in situations of single metastasis , the survival rate was less than two years and only three patients were in complete remission of their disease . one reason for these differences may come from the populations studied . in the literature , the prognostic factors for survival after resection for adrenal metastasis were variable , including tumor type , tumor size , operation occasion ( synchronous or metachronous ) , margin status , and previous surgery for metastases . .   found that body mass index ( bmi ) , tumor type , tumor size , and margin status were four independent prognostic factors of survival . concluded that increased bmi is associated with increased risk of common and less common malignancies . lo et al .   suggested that patients with metastases from adenocarcinoma had the best chances of survival . however , in our material , kidney cancer had the best survival period , whereas patients with melanoma and colon cancer had the worst survival . the difference in survival period may be attributed to the intrinsic biological behavior of different tumor types or presence of occult concurrent metastases in other organs . therefore all patients have to carefully undergo preoperative staging including chest , abdominal , and cerebral ct scans before the operation . strong et al .   reported that the < 4.5  cm group had a better survival period than the 4.5  cm group . in our study , the median survival period of the 3  cm group was 38 versus 6 months for the > 3  cm group . the difference may be attributed to the increased size of adrenal lesions correlated with the operative complexity and possible subsequent disease behavior . we also found that standard duration of surgery is statistically significant associated with better survival rate ( p = 0,024 ) , but these findings are limited by the low number of cases in our series . this result can be attributed to the different intrinsic biology of the tumors in the two groups ( metachronous versus synchronous ) . in the current study , the median survival period of the metachronous group was 10 versus 11 months for the synchronous group . the difference between the median survival for the patients with synchronous and metachronous metastases was not significant in our material ; thus we can not consider the time between findings of the primary tumor and the metastasis in adrenal gland as a strong survival predictor . in conclusion , many studies have documented that surgery for am contributes to a more favorable prognosis than when these tumors are not resected [ 3 , 30 ] . in agreement with zografos et al . our study shows that the retroperitoneal approach can be justified and is feasible for adrenal metastases less than 6  cm . minimally invasive surgery gives us an opportunity to minimize surgical trauma which also may be more tolerable to a patient with several previous surgical procedures . in summary , we found that era for am offers the same advantages as those amply reported for benign adrenal disease , with no morbidity and mortality , and the acceptable oncological results .
objectives . to evaluate whether retroperitoneal approach for adrenalectomy is a safe and effective treatment for adrenal metastases ( am ) . methods . from june 2004 to january 2014 , 
 nine consecutive patients with am were treated with endoscopic retroperitoneal adrenalectomy ( era ) . 
 a retrospective study was conducted , and clinical data , tumor characteristics , and oncologic outcomes were acquired and analyzed . results . 
 renal cancer was the primary site of malignancy in 44.4% of cases . 
 the mean operative time was 132    10.4  min . 
 there were 5 synchronous and 4 metachronous am . 
 one patient required conversion to transperitoneal laparoscopic procedure . no mortality or perioperative complications were observed . 
 the median overall survival was 11  months ( range : 242  months ) . 
 survival rates of 50% and 25% were identified at 1 and 3 years , respectively . at the end of the study , 
 4 patients were alive with a mean observed follow - up of 20 months . 
 no patients presented with local tumor relapse or port - site metastases . 
 conclusions . 
 this study shows that era is a safe and effective procedure for resection of am and advances the surgical treatment of adrenal disease . 
 the use of the retroperitoneal approach for adrenal tumors less than 6  cm can provide very favorable surgical outcomes .