***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 We conducted a r and omized , placebo-controlled , double-blind trial to determine whether the epidermal growth factor receptor inhibitor erlotinib prolongs survival in non-small-cell lung cancer after the failure of first-line or second-line chemotherapy . METHODS Patients with stage IIIB or IV non-small-cell lung cancer , with performance status from 0 to 3 , were eligible if they had received one or two prior chemotherapy regimens .  The patients were stratified according to center , performance status , response to prior chemotherapy , number of prior regimens , and prior platinum-based therapy and were r and omly assigned in a 2:1 ratio to receive oral erlotinib , at a dose of 150 mg daily , or placebo . RESULTS The median age of the 731 patients who underwent r and omization was 61.4 years ; 49 percent had received two prior chemotherapy regimens , and 93 percent had received platinum-based chemotherapy .  The response rate was 8.9 percent in the erlotinib group and less than 1 percent in the placebo group ( P<0.001 ) ; the median duration of the response was 7.9 months and 3.7 months , respectively . Progression-free survival was 2.2 months and 1.8 months , respectively ( hazard ratio , 0.61 , adjusted for stratification categories ; P<0.001 ) . Overall survival was 6.7 months and 4.7 months , respectively ( hazard ratio , 0.70 ; P<0.001 ) , in favor of erlotinib . Five percent of patients discontinued erlotinib because of toxic effects . CONCLUSIONS Erlotinib can prolong survival in patients with non-small-cell lung cancer after first-line or second-line chemotherapy PURPOSE To evaluate the efficacy and tolerability of two doses of gefitinib ( Iressa [ ZD1839 ] ; AstraZeneca , Wilmington , DE ) , a novel epidermal growth factor receptor tyrosine kinase inhibitor , in patients with pretreated advanced non-small-cell lung cancer ( NSCLC ) . PATIENTS AND METHODS This was a r and omized , double-blind , parallel-group , multicenter phase II trial . Two hundred ten patients with advanced NSCLC who were previously treated with one or two chemotherapy regimens ( at least one containing platinum )  were r and omly assigned to receive either 250-mg or 500-mg oral doses of gefitinib once daily . RESULTS Efficacy was similar for the 250- and 500-mg/d groups . Objective tumor response rates were 18.4 % ( 95 % confidence interval [ CI ] , 11.5 to 27.3 ) and 19.0 % ( 95 % CI , 12.1 to 27.9 ) ; among evaluable patients , symptom improvement rates were 40.3 % ( 95 % CI , 28.5 to 53.0 ) and 37.0 % ( 95 % CI , 26.0 to 49.1 ) ; median progression-free survival times were 2.7 and 2.8 months ; and median overall survival times were 7.6 and 8.0 months , respectively . Symptom improvements were recorded for 69.2 % ( 250 mg/d ) and 85.7 % ( 500 mg/d ) of patients with a tumor response . Adverse events ( AEs ) at both dose levels were generally mild ( grade 1 or 2 ) and consisted mainly of skin reactions and diarrhea . Drug-related toxicities were more frequent in the higher-dose group . Withdrawal due to drug-related AEs was 1.9 % and 9.4 % for patients receiving gefitinib 250 and 500 mg/d , respectively . CONCLUSION Gefitinib showed clinical ly meaningful antitumor activity and provided symptom relief as second- and third-line treatment in these patients . At 250 mg/d , gefitinib had a favorable AE profile . Gefitinib 250 mg/d is an important , novel treatment option for patients with pretreated advanced NSCLC [ corrected Purpose : Elevated levels or increases in circulating tumor cells ( CTC ) portend poor prognosis in patients with epithelial cancers . Less is known about CTCs as surrogate endpoints or their use for predictive biomarker evaluation . This study investigated the utility of CTC enumeration and characterization using the Cell Search platform , as well as mutation detection in circulating tumor DNA ( ctDNA ) , in patients with advanced non – small cell lung cancer ( NSCLC ) . Experimental Design : Forty-one patients were enrolled in a single-arm phase II clinical trial of erlotinib and pertuzumab .  Peripheral blood was analyzed for CTC enumeration , EGFR expression in CTCs , and detection of oncogenic mutations in CTCs and ctDNA . Changes in CTC levels were correlated with 2[18F]fluoro-2-deoxy-d-glucose – positron emission tomographic ( FDG-PET ) and computed tomographic ( CT ) imaging and survival endpoints . Results : CTCs were detected ( ≥1 CTC ) at baseline in 78 % of patients . Greater sensitivity for mutation detection was observed in ctDNA than in CTCs and detected mutations were strongly concordant with mutation status in matched tumor . Higher baseline CTC counts were associated with response to treatment by Response Evaluation Criteria in Solid Tumors ( RECIST , P = 0.009 ) and decreased CTC counts upon treatment were associated with FDG-PET and RECIST response ( P = 0.014 and P = 0.019 ) and longer progression-free survival ( P = 0.050 ) . Conclusion : These data provide evidence of a correlation between decreases in CTC counts and radiographic response by either FDG-PET or RECIST in patients with advanced NSCLC . These findings require prospect i ve validation but suggest a potential role for using CTC decreases as an early indication of response to therapy and ctDNA for real-time assessment of mutation status from blood . Clin Cancer Res ; 18(8 ) ; 2391–401 . © 2012 AACR CONTEXT More persons in the United States die from non-small cell lung cancer ( NSCLC ) than from breast , colorectal , and prostate cancer combined . In pre clinical testing , oral gefitinib inhibited the growth of NSCLC tumors that express the epidermal growth factor receptor ( EGFR ) , a mediator of cell signaling , and phase 1 trials have demonstrated that a fraction of patients with NSCLC progressing after chemotherapy experience both a decrease in lung cancer symptoms and radiographic tumor shrinkages with gefitinib . OBJECTIVE To assess differences in symptomatic and radiographic response among patients with NSCLC receiving 250-mg and 500-mg daily doses of gefitinib .  DESIGN , SETTING , AND PATIENTS Double-blind , r and omized phase 2 trial conducted from November 2000 to April 2001 in 30 US academic and community oncology centers . Patients ( N = 221 ) had either stage IIIB or IV NSCLC for which they had received at least 2 chemotherapy regimens . INTERVENTION Daily oral gefitinib , either 500 mg ( administered as two 250-mg gefitinib tablets ) or 250 mg ( administered as one 250-mg gefitinib tablet and 1 matching placebo ) . MAIN OUTCOME MEASURES Improvement of NSCLC symptoms ( 2-point or greater increase in score on the summed lung cancer subscale of the Functional Assessment of Cancer Therapy-Lung [ FACT-L ] instrument ) and tumor regression ( > 50 % decrease in lesion size on imaging studies ) . RESULTS Of 221 patients enrolled , 216 received gefitinib as r and omized . Symptoms of NSCLC improved in 43 % ( 95 % confidence interval [ CI ] , 33%-53 % ) of patients receiving 250 mg of gefitinib and in 35 % ( 95 % CI , 26%-45 % ) of patients receiving 500 mg . These benefits were observed within 3 weeks in 75 % of patients . Partial radiographic responses occurred in 12 % ( 95 % CI , 6%-20 % ) of individuals receiving 250 mg of gefitinib and in 9 % ( 95 % CI , 4%-16 % ) of those receiving 500 mg . Symptoms improved in 96 % of patients with partial radiographic responses . The overall survival at 1 year was 25 % . There were no significant differences between the 250-mg and 500-mg doses in rates of symptom improvement ( P = .26 ) , radiographic tumor regression ( P = .51 ) , and projected 1-year survival ( P = .54 ) . The 500-mg dose was associated more frequently with transient acne-like rash ( P = .04 ) and diarrhea ( P = .006 ) . CONCLUSIONS Gefitinib , a well-tolerated oral EGFR-tyrosine kinase inhibitor , improved disease-related symptoms and induced radiographic tumor regressions in patients with NSCLC persisting after chemotherapy Purpose : Activating mutations in the epidermal growth factor receptor ( EGFR ) are associated with enhanced response to EGFR tyrosine kinase inhibitors in non-small cell lung cancer ( NSCLC ) , whereas KRAS mutations translate into poor patient outcomes . We hypothesized that analysis of plasma for EGFR and KRAS mutations from shed tumor DNA would have clinical utility . Methods : An allele-specific polymerase chain reaction assay using Scorpion-amplification refractory mutation system ( DxS , Ltd ) was used to detect mutations in plasma DNA from patients with advanced stage NSCLC treated as second- or third-line therapy on a phase I/II trial of docetaxel plus intercalated erlotinib .  Results : EGFR mutations were detected in 10 of 49 patients ( 20 % ) . Six ( 12 % ) had single activating mutations in EGFR , associated with improved progression-free survival ( median , 18.3 months ) , compared with all other patients ( median , 3.9 months ; p = 0.008 ) , or those with wild-type EGFR ( median , 4.0 months ; p = 0.012 ) . Four of 49 patients harbored a de novo T790 M resistance mutation ( median progression-free survival , 3.9 months ) . EGFR mutational status was associated with clinical response ( 45 assessable , p = 0.0001 ) ; in the six patients with activating mutations , all achieved complete ( 33 % ) or partial ( 67 % ) response . All CR patients had E19del detectable in both tumor and plasma . KRAS mutations were detected in two of 49 ( 4 % ) patients , both of whom had rapid progressive disease . Conclusions : Activating EGFR mutations detected in shed DNA in plasma are significantly associated with favorable outcomes in patients with advanced NSCLC receiving docetaxel plus intercalated erlotinib . The addition of docetaxel in this schedule did not diminish the efficacy of erlotinib against patients with EGFR activating mutations Introduction : In IPASS ( IRESSA Pan-Asia Study ) , clinical ly selected patients with pulmonary adenocarcinoma received first-line gefitinib or carboplatin/paclitaxel . This preplanned , exploratory analysis was conducted to increase underst and ing of the use of surrogate sample s , such as serum , versus tumor biopsy sample s for determining EGFR mutation status in the Japanese cohort ( n = 233 ) . Methods : EGFR mutations were assessed using tumor tissue-derived DNA ( n = 91 ) and circulating free ( cf ) DNA from pretreatment serum sample s ( n = 194 ) . Results : Fewer patients were  EGFR mutation positive when assessed using pretreatment cfDNA ( 23.7 % ) versus tumor tissue-derived DNA ( 61.5 % ) . cfDNA results identified no false positives but a high rate of false negatives ( 56.9 % ) . There was a significant interaction between cfDNA EGFR mutation status and treatment for progression-free survival ( PFS ) ( p = 0.045 ) . PFS was significantly longer and objective response rate ( ORR ) higher with gefitinib than carboplatin/paclitaxel in the cfDNA EGFR mutation-positive subgroup ( PFS : hazard ratio [ HR ] , 0.29 ; 95 % confidence interval [ CI ] , 0.14–0.60 ; p < 0.001 ; ORR : odds ratio [ OR ] , 1.71 ; 95 % CI , 0.48–6.09 ; 75.0 % versus 63.6 % ; p = 0.40 ) . There was a slight numerical advantage in PFS and ORR for gefitinib over carboplatin/paclitaxel in the cfDNA EGFR mutation-negative subgroup , likely due to the high rate of false negatives within this subgroup . Conclusions : These results merit further investigation to determine whether alternative sources of tumor DNA , such as cfDNA in serum , could be used for determining EGFR mutation status in future ; currently , where a sample is available , analysis of tumor material is recommended BACKGROUND Patients with non- 
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Importantly , the association of the mutations with the 3 clinical outcomes for serum was similar to that for tumor tissue and higher than that for plasma .
Blood , in particular serum , is a good substitute when tumor tissue is absent or insufficient for testing EGFR mutations to guide EGFR TKIs treatment in patients with NSCLC .