***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: To evaluate the effect of percutaneous ethanol injection ( PEI ) in the treatment of large compressive thyroid cystic nodules ( TCN ) , we studied 20 patients , potential c and i date s for surgery ( tracheal displacement , nodule volume over 10 mL at ultrasonography ) and not cured by aspiration alone : 14 experienced a recurrence after two complete evacuations of cystic fluid ( watery nodules , WN ) ; in six an aspiration was impossible because the cystic fluid was very thick ( viscous nodules , VN ) . To exclude malignancy , both cytocentrifugate from WN and the smears from VN were examined . WN were treated with 1 - 4 sessions of conventional PEI ; in VN a first PEI session was performed with the purpose of reducing the density of cystic fluid ; then if cystic fluid was successfully aspirated , one or more PEI sessions were performed . Thyroid palpation , ultrasonography with nodule volume assessment , and assays for FT3 , FT4 , and TSH were performed 1 and 6 months after the last PEI . At month 6 , 17 patients ( 85 % ) had volume reduction of more than 90 % of the initial nodule volume ; in 2 patients ( 10 % ) there was a reduction between 50 and 90 % , and in one patient ( 5 % ) an appreciable swelling persisted after 3 injections . Nodule volume was significantly decreased below baseline at month 1 ( 10.9 + /- 13.3 vs 39 + /- 24 mL , p < 0.001 ) , with a further reduction at month 6 ( 5 + /- 11.7 mL , p < 0.01 vs 1st month value ) . In most of the nodules the cystic portion completely disappeared ; the residual tissue showed fibrous features , often with calcifications . In 11 patients follow-up was prolonged over the sixth month ( 15 + /- 4 months ) ; the nodule volume did not significantly differ from the sixth month ( 3 + /- 2.2 mL ) and the end of the follow-up ( 2.8 + /- 2.3 mL ) . In conclusion , we demonstrate that PEI may be a safe and effective procedure in the treatment of large TCN PURPOSE To prospect ively evaluate the efficacy of additional radiofrequency ( RF ) ablation by comparing the results of one and two sessions . MATERIAL S AND METHODS All patients gave written informed consent to participate in this institutional review board-approved prospect i ve study . From September 2007 to February 2008 , 30 patients with benign predominantly solid thyroid nodules causing pressure symptoms and /or cosmetic problems were r and omly assigned to undergo single-session ( group 1 , n = 15 ) or two-session ( group 2 , n = 15 ) RF ablation . RF ablation was performed by using an 18-gauge internally cooled electrode with ultrasonographic guidance . Nodule volume and cosmetic and symptom scores were evaluated before ablation and at 1 , 3 , and 6 months after initial ablation , and quantitative comparisons of these were performed by using the Mann-Whitney and Wilcoxon signed rank tests ; the Spearman rank test was used for correlation between nodule volume reduction and applied energy . RESULTS At 6-month follow-up , there was significant nodule volume reduction , from 13.3 mL ± 12.9 ( st and ard deviation ) to 3.8 mL ± 4.4 in group 1 ( P = .001 ) , and from 13.0 mL ± 6.8 to 3.0 mL ± 2.2 in group 2 ( P = .001 ) . Each group showed significant improvement in cosmetic ( P < .0001 ) and symptom ( P = .001 ) scores . However , there was no significant difference in volume reduction , cosmetic score , and symptom score between two groups ( P = .078 , P > .99 , and P = .259 , respectively ) . In group 1 , three of four patients who had a pretreatment nodule volume larger than 20 mL underwent additional RF ablation because of unresolved clinical problems after the first session . CONCLUSION Single-session RF ablation showed significant volume reduction and satisfactory clinical response in most patients . Therefore , additional RF ablation should be limited to patients with a large nodule ( > 20 mL ) or unresolved clinical problems The aim of this study was to evaluate the effect of combined cyst aspiration and ultrasound-guided interstitial laser photocoagulation ( ILP ) on recurrence rate and the volume of benign cystic thyroid nodules .  10 euthyroid out patients with a solitary and cytologically benign partially cystic thyroid nodule causing local discomfort were assigned to cyst aspiration followed by ultrasound-guided ILP and followed for 12 months . The ILP was performed under continuous ultrasound-guidance and with an output power of 2.5 - 3.5 W. The volume of the nodules was assessed by means of ultrasound and determination of the amount of aspirated cyst fluid , thereby calculating the volume of the solid part . Follow-up included ultrasound and determination of thyroid function . Pressure and cosmetic complaints were evaluated on a visual analogue scale . The median initial volume of the cystic nodule decreased from 9.6 ml [ 6.8;15.5 ( quartiles ) ] to 3.5 ml [ 2.7;9.0 ( quartiles ) ] ( p = 0.0001 ) , and the median cyst volume from 3.0 ml [ 2.0;6.0 ( quartiles ) ] to 0 ml [ 0;0.5 ( quartiles ) ] ( p = 0.0001 ) during follow-up . Recurrence of the cystic part was defined as a cyst volume > 1 ml . In eight of 10 patients there was no recurrence of the cystic part . Both pressure symptoms and cosmetic complaints were significantly reduced . The only side effect was mild pain or tenderness for a few days . Our study suggests that complete cyst aspiration and subsequent ultrasound-guided ILP of benign cystic thyroid nodules is a feasible and safe technique , result ing in a significant reduction in the volume of both the solid and the cystic component . A large-scale prospect i ve r and omized study is warranted AIM OF THE STUDY To compare clinical and ultrasound ( US ) changes induced in cold thyroid nodules by US-guided percutaneous laser ablation ( PLA ) versus follow-up or levothyroxine ( LT4 ) suppressive therapy . METHODS 62 patients r and omly assigned to a single  PLA ( Group 1 ) , LT4 ( Group 2 ) , or follow-up ( Group 3 ) . Entry criteria : euthyroid patients with a solid thyroid nodule > 5 mL and benign cytological findings . TREATMENT Group 1 : PLA was performed with a 1.064 mum neodymium yttrium-aluminum-garnet laser with output power of 3 W for 10 minutes ; Group 2 : the LT4 dose was adjusted to induce thyrotropin suppression ; Group 3 : no treatment . RESULTS In Group 1 a significant nodule reduction was found 6 and 12 months after PLA ( delta volume : -42.7 + /- 13.6 % ; p = 0.001 ) . A reduction > 50 % was found in 33.3 % of cases . In Group 2 a nonsignificant nodule shrinkage was observed . A nonsignificant volume increase was observed in Group 3 . Improvement of local symptoms was registered in 81.2 % of patients in Group 1 vs. 13.3 % in Group 2 and 0.0 % in Group 3 ( p = 0.001 ) . No complications were noted . CONCLUSIONS A single PLA induced significant volume reduction and improvement of local symptoms .  PLA was more effective than LT4 . Follow-up was associated with nodule growth and progression of local symptoms .  PLA should be considered a potential mini-invasive alternative to surgery in symptomatic patients with benign cold thyroid nodules Abstract Objectives To compare the efficacy of ethanol ablation ( EA ) of cystic and predominantly cystic thyroid nodules , and to evaluate factors affecting efficacy . Methods From October 2008 to December 2010 , a total of 217 thyroid nodules were treated with EA . Nodule volumes , symptoms and cosmetic scores were evaluated before and after EA . EA efficacy in treating cystic and predominantly cystic nodules was compared ; and factors related to EA efficacy in each type , including initial volume , solid component , vascularity , fluid nature , ethanol retention time and number of EA sessions , were evaluated . Results Mean nodule volume decreased from 15.7 ± 18.1 ml to 3.0 ± 7.9 ml ( mean volume reduction , 85.2 ± 16.1 % ) and the therapeutic success rate was 90.3 % at last follow-up . EA  was significantly more effective in cystic than predominantly cystic nodules . Independent predictors of  EA  efficacy for all nodules included initial volume , solid component and vascularity . Initial volume and vascularity were independent predictors of EA efficacy in predominantly cystic nodules , but no factor was independently related to efficacy in cystic nodules . Conclusions EA is effective in both cystic and predominantly cystic nodules , especially the former . EA is less effective in large or vascular predominantly cystic nodules , but is effective in cystic nodules regardless of related factors . Key Points• Ethanol ablation under ultrasound guidance is increasingly used for cystic thyroid nodules .  • EA seems effective for cystic and predominantly cystic nodules , especially cystic nodules . • The  effectiveness of EA was reduced in large or vascular predominantly cystic nodules Methods for combining data from several studies exist and appear to be quite useful . None satisfactorily addresses the question of what studies should be combined . This issue is the most serious method ological limitation . Even studies with statistically significant interaction might still be combined if the effect were in the same direction . Thus , substantial scientific input is required as to what criteria must be met by each potential study . Much can be learned from combining or pooling data but it must be done cautiously . Pooling exercises do not replace well design ed prospect i ve clinical trials . Efforts for establishing basic design criteria to allow for multicentre and multicountry trials to be more easily combined might be useful . AIM To evaluate the long-term efficacy of interstitial laser photocoagulation ( ILP ) in solitary benign thyroid nodules . DESIGN AND METHODS A total of 78 euthyroid out patients ( 45 participating in r and omized trials ) with a benign solitary solid and scintigraphically cold thyroid nodule causing local discomfort were assigned to ILP . ILP ( using one laser fiber ) was performed under continuous ultrasound ( US ) guidance and with an output power of 1.5 - 3.5 W. Thyroid nodule volume was assessed by US and thyroid function determined by routine assays , before and during follow-up . Pressure symptoms and cosmetic complaints were evaluated on a visual analogue scale ( 0 - 10 cm ) . Of the total patients , six had thyroid surgery 6 months after ILP and three were lost to follow-up . The median follow-up for the remaining 69 patients was 67 months ( range 12 - 114 ) . RESULTS The overall median nodule volume decreased from 8.2 ml ( range 2.0 - 25.9 ) to 4.1 ml ( range 0.6 - 33.0 ; P<0.001 ) at the final evaluation , corresponding to a median reduction of 51 % ( range : -194 to 95 % ) . This correlated with a significant decrease in pressure as well as cosmetic complaints . After 12 - -96 months ( median 38 months ) of ILP , 21 patients ( 29 % ) had thyroid surgery because of an unsatisfactory result . All had benign histology . Thyroid function was unaltered throughout and side effects were restricted to mild local pain . CONCLUSION US-guided ILP results in a satisfactory long-term clinical response in the majority of patients with a benign solitary solid cold thyroid nodule . Further large-scale studies should aim at optimizing selection criteria for ILP , preferably in r and omized studies BACKGROUND Percutaneous radiofrequency thermal ablation ( RTA ) is a promising new therapeutic approach to manage thyroid nodules ( TNs ) . The aim of this study was to investigate the long-term effectiveness of RTA in inducing shrinkage of TNs as well as in controlling compressive symptoms and thyroid hyperfunction in a large series of elderly subjects with solid or mainly solid benign TNs . METHODS Ninety-four elderly patients with cytologically benign compressive TNs were prospect ively enrolled in the study ; 66 of them had nontoxic goiter and 28 had toxic or pretoxic goiter .  RTA was performed by using a RITA StarBurst Talon hook-umbrella needle inserted in every single TN under ultrasonographic real-time guidance .  TN volume , TN-related compressive symptoms and thyroid function were evaluated at baseline and 12 to 24 months after RTA . RESULTS All TNs significantly decreased in size after RTA . The mean decrease in TN volume 12 months after RTA was from 24.5 + /- 2.1 to 7.5 + /- 1.2 mL ( p < 0.001 ) , with a mean percent decrease of 78.6 + /- 2.0 % . Two years after RTA 
    Output:
    
There were no major complications after either RFA or LA .
CONCLUSIONS RFA appears to be superior to LA in reducing benign solid thyroid nodule volume , despite the smaller number of treatment sessions without major side effects