***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: BACKGROUND / AIMS Vitamin K2 ( VK2 ) appears to have a potent inhibitory activity for cell growth including HCC cells . We investigated whether VK2 could reduce incidence of tumor recurrence after treatment of HCC . Forty-five patients with cured or possibly cured HCC were r and omly selected , assigning patients to treatment ( n=21 ) or control group ( n=24 ) with r and omization list . METHODOLOGY For the treatment group , forty-five mg of Glakay was given orally every day after therapy for HCC . No patients complained of adverse effects .  Abdominal ultrasonography and dynamic CT were performed at 3-month intervals . Recurrence was confirmed by abdominal angiography . RESULTS Recurrence of HCC occurred in 7 cases ( 33.3 % ) for the treatment group and 12 cases ( 50.0 % ) for the control group during mean observation periods of 19.5 and 16.5 months , respectively . Administration of VK2 was not an independent variable for the recurrence on univariate analysis . Cumulative incidence of HCC recurrence did not differ between the two groups , and the cumulative survival rate tended to be high in treatment group ( p = 0.054 ) . Cox regression analysis revealed that serum albumin concentration alone was an independent factor affecting the recurrence . CONCLUSIONS These findings suggest that VK2 does not appear to prevent recurrence of HCC after curative treatment . Our study is preliminary and large-scale trials are needed to determine whether VK2 is of benefit to decrease the recurrence of HCC BACKGROUND Despite the progression of therapeutic approaches , a high frequency of recurrence is what determines the long-term prognosis of patients with hepatocellular carcinoma ( HCC ) . In this study , the chemopreventive effects of vitamin K2 on the recurrence and survival of patients with HCC after curative therapy were evaluated . METHODS Sixty patients who were diagnosed to be free of HCC after radiofrequency ablation therapy or surgery were r and omly assigned to either the vitamin K2 group ( n = 30 patients ) or the control group ( n = 30 patients ) . All patients were positive for the hepatitis C virus ( HCV ) antibody and hepatitis B surface antigen positive patients were excluded from this study . Patients in the vitamin K2 group received an oral dose of menatetrenone at 45 mg per day . Disease recurrence and the survival rates were analyzed in patients with HCC . RESULTS The cumulative recurrence-free rates in the vitamin K2 group were 92.3 % at 12 months , 48.6 % at 24 months and 38.8 % at 36 months ; and those in the control group were 71.7 % , 35.9 % and 9.9 % , respectively ( P = 0.045 ) . The cumulative survival rates in the vitamin K2 group were 100 % at 12 months , 95.0 % at 24 months and 77.5 % at 36 months ; and those in the control group were 95.8 % , 90.2 % and 66.4 % , respectively ( P = 0.70 ) . CONCLUSIONS Vitamin K2 may have a suppressive effect on the recurrence of HCC and a beneficial effect on tumor recurrence . However , there was no significant difference in the survival rates . The chemopreventive effects of vitamin K2 are not sufficient . The development of a further regimen such as combination therapy is required A goal of cancer chemoprevention is the deletion of latent premalignant or malignant clones before they exp and to a clinical ly detectable tumor . However , such clonal deletion has not been demonstrated in clinical studies . We have evaluated serum levels of lectin-reactive alpha-fetoprotein ( AFP-L3 ) , which suggests the presence of latent hepatoma cells , in a r and omized controlled trial that used acyclic retinoid to prevent second primary hepatomas in patients who had received treatments that cured initial hepatomas . The trial involved 21 patients in each acyclic retinoid ( 600 mg daily ) and placebo group and consisted of a 12-month period of drug administration and a subsequent follow-up period . Serum AFP-L3 was determined at entry and at the end of the 12-month treatment period using lectin-affinity electrophoresis and antibody-affinity blotting . Although neither treatment affected serum levels of total AFP , acyclic retinoid significantly reduced AFP-L3 levels after a 12-month administration ( P < 0.01 ) . Acyclic retinoid not only deleted AFP-L3 from patients who had been positive for AFP-L3 at entry but also prevented the appearance of AFP-L3 in patients who had been negative at entry ( P < 0.01 ) . In contrast , placebo significantly raised the incidence of AFP-L3-positive patients after a 12-month administration from that at entry ( P < 0.05 ) . Patients positive for AFP-L3 after a 12-month treatment had a significantly higher risk of second primary hepatomas in the subsequent follow-up period ( P = 0.03 ) . Acyclic retinoid may have deleted a clone of latent hepatoma cells producing AFP-L3 and thereby inhibited second primary hepatomas . Serum AFP-L3 may be a useful intermediate biomarker in the chemoprevention of second primary hepatomas by acyclic retinoid Objective : To compare the efficacy and safety of partial hepatectomy aim ing grossly at a narrow ( 1 cm ) and a wide ( 2 cm ) resection margin in patients with macroscopically solitary hepatocellular carcinoma ( HCC ) . Summary Background Data : For HCC treated with partial hepatectomy , the extent of the margin of liver resection remains controversial despite extensive studies . Methods : We conducted a prospect i ve r and omized trial in patients with solitary HCC . From January 1999 to February 2003 , 169 patients with solitary HCC were stratified according to tumor size and r and omized to undergo partial hepatectomy aim ing grossly at either a narrow ( 1 cm ) ( n = 84 ) or a wide resection margin ( 2 cm ) ( n = 85 ) . Analyses were done on an intention-to-treat basis . Results : The demographic and pathologic data were similar in the 2 groups . The mean ± SD for the final resection margin of the narrow and the wide margin groups were 0.7 ± 0.4 cm and 1.9 ± 0.6 cm , respectively . There was no significant difference in the morbidity and in-hospital mortality between the 2 groups of patients . The 1- , 2- , 3- , and 5-year overall survival rates for the narrow and the wide margin groups were 92.9 % , 83.3 % , 70.9 % , and 49.1 % and 96.5 % , 91.8 % , 86.9 % , and 74.9 % , respectively . The difference was significant ( stratified log-rank test , P = 0.008 ) . Multivariate analysis identified the presence of micrometastases and the treatment allocation were independent risk factors for tumor-related death . At the time of censor , 75 ( 44.4 % ) patients had developed tumor recurrence . All recurrences at the margins of liver resection were observed in the narrow margin group . Multiple tumor recurrence was also significantly higher in the narrow margin group ( & khgr;2 test , P = 0.018 ) . Survival after tumor recurrence was significantly better in the wide margin group than the narrow margin group ( log-rank test , P = 0.017 ) . Conclusion : For macroscopically solitary HCC , a resection margin aim ing grossly at 2 cm efficaciously and safely decreased postoperative recurrence rate and improved survival outcomes when compared with a gross resection margin aim ing at 1 cm , especially for HCC ≤2 cm Retinoid is a collective term which indicates vitamin A ( retinol ) and its derivatives . Retinoid has a variety of functions such as growth promotion , maintenance of reproduction and dark adaptation .  Retinoid also regulates cell differentiation and tissue morphogenesis . Sinceabnormality in the differentiation induces cellular atypia and that of the morphogenesis induces structural atypia , retinoid has important effects which inhibit carcinogenesis 
    Output:
    
The beneficial effect on the overall survival was less definite .
There is evidence to suggest that chemopreventive therapy after partial hepatectomy or local ablative therapy is beneficial in prolonging disease-free survival , but the evidence is less for an effect on the overall survival .