***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Background : Although early gastric cancer ( T1 , NX ) in Japan has been reported to have an excellent prognosis , the experience with this cancer in the United States is limited . The treatment of these tumors in Japan is becoming less aggressive as “ good prognostic factors ” are increasingly recognized . Our objective was to identify predictors of nodal disease and survival in a large cohort of Western patients with T1 tumors . Methods : A retrospective review of our prospect i ve data base from July 1985 to March 1998 revealed 165 patients undergoing surgical resection for T1 gastric tumors . Clinicopathological factors analyzed and compared included presence of positive nodes , tumor size ( 4.5 vs.,4.5 cm ) , depth ( mucosal vs. submucosal ) , grade ( poor vs. moderate and well ) , and tumor site ( proximal vs. distal ) , presence of venous or perineural invasion , and Lauren ’s classification . Factors predicting lymph node involvement and disease-specific survival were evaluated by univariate and multivariate analysis . Results : Median follow-up time was 36 months . The actuarial 5-year survival was 88 % . Thirteen patients ( 8 % ) died of disease . Lymph node involvement was present in 31 tumors ( 19 % ) , with a 5-year survival of 91 % with negative nodes vs. 78 % with positive nodes . On univariate and multivariate analysis , the presence of tumor submucosal invasion ( P,.05 ) , venous invasion ( P 5.02 ) , and size of 4.5 cm and larger ( P 5.02 ) was significantly associated with an increased risk for nodal positivity . On univariate analysis of survival , node-positive tumors ( P 5.02 ) and tumors 4.5 cm and larger ( P 5.008 ) were significantly associated with decreased survival . On multivariate analysis , only node-positive tumors were significantly ( P 5.01 ) associated with decreased survival . Those tumors that were limited to the mucosa and less than 4.5 cm in size ( n = 47 ) had a 4 % rate of positive nodes . In contrast , those tumors that were 4.5 cm and larger and had penetrated into the submucosa ( n = 16 ) had a 56 % chance of positive nodes . Conclusions : Early gastric carcinoma in North America has an excellent prognosis , similar to that in Japan . Tumors that are limited to the mucosa and smaller than 4.5 cm could be considered for limited resection without lymphadenectomy BACKGROUND In Japan the surgical approach to treatment of potentially curable gastric cancer , including extended lymphadenectomy , seems in retrospective surveys to give better results than the less radical procedures favoured in Western countries . There has , however , been no evidence from r and omised trials that extended lymphadenectomy ( D2 gastric resection ) confers a survival advantage . This question was addressed in a trial involving thirty-two surgeons in Europe . METHODS In a prospect i ve r and omised controlled trial , D1 resection ( level 1 lymphadenectomy ) was compared with D2 resection ( levels 1 and 2 lymphadenectomy ) . Central r and omisation ( 200 patients in each arm ) followed a staging laparotomy . FINDINGS The D2 group had greater postoperative hospital mortality ( 13 % vs 6.5 % ; p=0.04 [ 95 % Cl 9 - 18 % for D2 , 4 - 11 % for D1 ] and higher overall postoperative morbidity ( 46 % vs 28 % ; p<0.001 ) ; their postoperative stay was also longer . The excess postoperative morbidity and mortality in the D2 group was accounted for by distal pancreaticosplenectomy and splenectomy . In the whole group ( 400 patients ) , survival beyond three years was 30 % in patients whose gastrectomy included en-bloc pancreatico-splenic resection versus 50 % in the remainder . INTERPRETATION D2 gastric resections are followed by higher morbidity and mortality than D1 resections . These disadvantages are consequent upon additional pancreatectomies and distal splenectomies , and in long-term follow-up the higher mortality when the pancreas and spleen are resected may prove to nullify any survival benefit from D2 procedures The contention that the R2 radical gastrectomy for localized and potentially curable gastric carcinoma may be superior to gastrectomy without lymphadenectomy ( R1 ) was assessed by r and omized trial . Five years after commencement 403 patients have been evaluated at surgery and only 43 ( 11 per cent ) found eligible ( S0–2 , P0 , H0 , N0–1 ) , 22 of whom underwent R1 and 21 R2 gastrectomy .  Seven patients had final histological stages in excess of the protocol . The R2 group had a longer operating time ( P<0.005 ) , a greater blood transfusion requirement ( P<0.005 ) , a longer hospital stay ( 0.05>P>0.025 ) and required reoperation in four cases . There were no postoperative deaths . Four patients have died from the disease in the R1 group and five in the R2 group , there being no difference in the probability of survival at a median follow‐up of 3.1 years . The small proportion of patients suitable for radical R2 surgery , the high associated morbidity and the fact that survival advantage has yet to be proven in trial suggest that this procedure should not yet be performed outside of controlled clinical trials This prospect i ve r and omized study compared the survival of patients with tumour node metastasis ( TNM ) stage T2 N1–2 gastric cancer treated by gastrectomy alone or gastrectomy followed by uracil – tegafur BackgroudApplication of laparoscopy-assisted distal gastrectomy ( LADG ) for early gastric cancer ( EGC ) is still controversial because of scant evidence of long-term safety and feasibility . We evaluated the long-term outcome of LADG compared with conventional open distal gastrectomy ( ODG ) for EGC . Methods Between March 1999 and July 2006 , 106 patients underwent LADG and 105 patients underwent ODG for EGC .  Clinicopathologic characteristics , postoperative outcomes , hospital course , postoperative morbidity , postoperative mortality , and long-term outcomes , including cancer recurrence and survival , were retrospectively compared between the two groups . Survival of all patients was confirmed with 55-month median follow-up . Results Postoperative recovery was significantly faster in the LADG group ; passing flatus occurred earlier , starting a liquid diet began sooner , and postoperative hospital stay was shorter ( p < 0.05 ) . Mean operation time was significantly longer in the LADG group . Postoperative complications in the LADG group occurred less frequently compared with in the ODG group ( 4.7 % versus 13.3 % , p = 0.046 ) . Tumor recurrence occurred in two cases ( 0.9 % ) and death related to recurrence occurred in only one patient ( 0.5 % ) . Overall 5-year survival rate ( 5-YSR ) of all patients was 95.5 % , while disease-specific 5-YSR was 98.8 % . There was no significant difference in survival rates between the two groups ; overall 5-YSR of the ODG and LADG groups was 94.9 % and 95.9 % , respectively . Conclusions Our data suggest that LADG for EGC is feasible and safe . We expect the results of the present study to be confirmed by prospect i ve r and omized analysis Curative resection is the treatment of choice for potentially curable gastric cancer . Two major Western studies in the 1990s failed to show a benefit from D2 dissection . They showed extremely high postoperative mortality after D2 dissection , and were criticised for the potential inadequacy of the pretrial training in the new technique of D2 dissection , prior to the phase III studies being initiated . The inclusion of pancreatectomy and splenectomy in D2 dissection was associated with increased morbidity and mortality . Following these results , we started a phase II trial to evaluate the safety and efficacy of pancreas-preserving D2 dissection . The results of this trial regarding the safety of pancreas preserving D2 dissection were published in 1998 . In this paper , we present the survival results of this phase II trial to confirm the rationale of carrying out a phase III study comparing D1 vs D2 dissection for curable gastric cancer . Italian patients with histologically proven gastric adenocarcinoma were registered in the Italian Gastric Cancer Study Group Multicenter trial . The study was carried out based on the General Rules of the Japanese Research Society for Gastric Cancer . A strict quality control system was achieved by a supervising surgeon of the reference centre who had stayed at the National Cancer Center Hospital , Tokyo , to learn the st and ard D2 gastrectomy and the postoperative management . The st and ard procedure entailed removal of the first and second tier lymph nodes . During total gastrectomy , the pancreas was preserved according to the Maruyama technique . Complete follow-up was available to death or 5 years in 100 % of patients and the median follow-up time was 4.38 years . Out of 297 consecutive patients registered , 191 patients were enrolled in the study between May 1994 and December 1996 . The overall morbidity rate was 20.9 % . The postoperative in-hospital mortality was 3.1 % . The overall 5-year survival rate among all eligible patients was 55 % . Survival was strictly related to stage , depth of wall invasion , lymph node involvement and type of gastrectomy ( distal vs total).Our results suggest a survival benefit for pancreas-preserving D2 dissection in Italian patients with gastric cancer if performed in experienced centres . A phase III trial among exclusively experienced centres is urgently needed BACKGROUND A multicenter , r and omized , clinical trial was initiated to evaluate the possible benefits of extended D2 ( D2 + ) lymphadenectomy after potentially curative resection of gastric cancer . METHODS St and ard D2 lymphadenectomy was defined according to the Japanese Gastric Cancer Association classification . D2 + lymph node dissection additionally included the removal of para-aortic nodes . RESULTS Of 781 patients screened , 275 were r and omized to st and ard D2 ( n = 141 ) or extended D2 + ( n = 134 ) lymphadenectomy . The overall morbidity rates were comparable in D2 ( 27.7 % ; 95 % confidence interval [ CI ] , 20.3 - 35.1 ) and D2 + ( 21.6 % ; 95 % CI , 13.7 - 29.5 ) groups ( P = .248 ) . Pre-existing cardiac disease , splenectomy , and excessive blood loss were identified as risk factors for overall and nonsurgical complications . Postoperative mortality rates were 4.9 % ( 95 % CI , 1.4 - 8.5 ) and 2.2 % ( 95 % CI , 0 - 4.7 ) , respectively ( P = .376 ) . CONCLUSIONS The interim safety analysis failed to show any significant difference with regard to the extent of lymph node dissection . The surgical outcome was not different between the 2 surgeries Background The prognosis of patients with gastric cancer and para-aortic lymph node ( PALN ) metastasis is poor . Recent Japanese r and omized trials concluded that prophylactic PALN dissection is not effective for curable advanced gastric cancer . However , the value of curative resection in patients with pathologically positive PALN is not determined yet . Methods We retrospectively identified 178 patients with pathologically positive PALN who underwent curative resection at the Cancer Institute Hospital from 1980 to 2004 . Patient characteristics were analyzed and independent prognostic factors for death were identified by Cox proportional hazard model . Results Partial gastrectomy was the most frequently performed procedure ( 142 of 178 ) . Postoperative morbidity and mortality rates were 30 and 2 % , respectively , with a 5-year survival rate of 13.0 % . Multivariate analysis revealed the total number of positive nodes ( hazard ratio , 1.804 ; 95 % confidence interval , 1.221–2.665 ) and macroscopic type ( hazard ratio , 1.697 ; 95 % confidence interval , 1.138–2.530 ) as independent prognostic factors , while age , sex , histology , pathological tumor depth , and degree of PALN dissection were not statistically significant . The 5-year survival rate increased to 28.6 % in patients with ≤15 positive nodes and macroscopic type other than type 4 . Conclusions Prophylactic PALN dissection can not be justified in curable advanced gastric cancer . However , R0 resection including PALN retrieval might be beneficial in patients with pathologically positive PALN , providing patients are carefully selected and operations are performed safely BACKGROUND / AIMS A r and omized study was performed to evaluate morbidity and mortality after D2 ( level 1 and 2 lymphadenectomy ) and D4 ( D2 plus lymphadenectomy of para-aortic lymph nodes ) dissection for advanced gastric cancer . METHODOLOGY Two hundred and fifty-six patients with advanced gastric adenocarcinoma were enrolled ( 128 to each group ) . Patients were r and omly allocated into D2 ( N = 128 ) or D4 ( N = 128 ) group . The first and second tiers of lymph nodes 
    Output:
    
Two large western r and omized trials , meta-analyses and a recent systematic review were unable to demonstrate overall benefit from extended lymphadenectomy .