***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: PURPOSE In metastatic colorectal cancer , phase III studies have demonstrated the superiority of fluorouracil ( FU ) with leucovorin ( LV ) in combination with irinotecan or oxaliplatin over FU + LV alone . This phase III study investigated two sequences : folinic acid , FU , and irinotecan ( FOLFIRI ) followed by folinic acid , FU , and oxaliplatin ( FOLFOX6 ; arm A ) , and FOLFOX6 followed by FOLFIRI ( arm B ) . PATIENTS AND METHODS Previously untreated patients with assessable disease were r and omly assigned to receive a 2-hour infusion of l-LV 200 mg/m(2 ) or dl-LV 400 mg/m(2 ) followed by a FU bolus 400 mg/m(2 ) and 46-hour infusion 2,400 to 3,000 mg/m(2 ) every 46 hours every 2 weeks , either with irinotecan 180 mg/m(2 ) or with oxaliplatin 100 mg/m(2 ) as a 2-hour infusion on day 1 . At progression , irinotecan was replaced by oxaliplatin ( arm A ) , or oxaliplatin by irinotecan ( arm B ) . RESULT Median survival was 21.5 months in 109 patients allocated to FOLFIRI then FOLFOX6 versus 20.6 months in 111 patients allocated to FOLFOX6 then FOLFIRI ( P = .99 ) . Median second progression-free survival ( PFS ) was 14.2 months in arm A versus 10.9 in arm B ( P = .64 ) . In first-line therapy , FOLFIRI achieved 56 % response rate ( RR ) and 8.5 months median PFS , versus FOLFOX6 which achieved 54 % RR and 8.0 months median PFS ( P = .26 ) . Second-line FOLFIRI achieved 4 % RR and 2.5 months median PFS , versus FOLFOX6 which achieved 15 % RR and 4.2 months PFS . In first-line therapy , National Cancer Institute Common Toxicity Criteria grade 3/4 mucositis , nausea/vomiting , and grade 2 alopecia were more frequent with FOLFIRI , and grade 3/4 neutropenia and neurosensory toxicity were more frequent with FOLFOX6 . CONCLUSION Both sequences achieved a prolonged survival and similar efficacy . The toxicity profiles were different BACKGROUND In the non-curative setting , the sequence in which anticancer agents are used , singly or in combination , may be important if patients are to receive the maximum period of disease control with the minimum of adverse effects . We compared sequential and combination chemotherapy strategies in patients with unpretreated advanced or metastatic colorectal cancer , who were regarded as not potentially curable irrespective of response . METHODS We studied patients with advanced colorectal cancer , starting treatment with non-curative intent . 2135 unpretreated patients were r and omly assigned to three treatment strategies in the ratio 1:1:1 . Strategy A ( control group ) was single-agent fluorouracil ( given with levofolinate over 48 h every 2 weeks ) until failure , then single-agent irinotecan . Strategy B was fluorouracil until failure , then combination chemotherapy . Strategy C was combination chemotherapy from the outset . Within strategies B and C , patients were r and omly assigned to receive , as the combination regimen , fluorouracil plus irinotecan ( groups B-ir and C-ir ) or fluorouracil plus oxaliplatin ( groups B-ox and C-ox ) . The primary endpoint was overall survival , analysed by intention to treat . This study is registered as an International St and ard R and omised Controlled Trial , number IS RCT N 79877428 . RESULTS Median survival of patients allocated to control strategy A was 13.9 months . Median survival of each of the other groups was longer ( B-ir 15.0 , B-ox 15.2 , C-ir 16.7 , and C-ox 15.4 months ) . However , log-rank comparison of each group against control showed that only C-ir -- the first-line combination strategy including irinotecan -- satisfied the statistical test for superiority ( p=0.01 ) . Overall comparison of strategy B with strategy C was within the predetermined non-inferiority boundary of HR=1.18 or less ( HR=1.06 , 90 % CI 0.97 - 1.17 ) . INTERPRETATION Our data challenge the assumption that , in this non-curative setting , maximum tolerable treatment must necessarily be used first-line . The staged approach of initial single-agent treatment up grade d to combination when required is not worse than first-line combination , and is an alternative option for discussion with patients Summary Background When cure is impossible , cancer treatment should focus on both length and quality of life . Maximisation of time without toxic effects could be one effective strategy to achieve both of these goals . The COIN trial assessed preplanned treatment holidays in advanced colorectal cancer to achieve this aim . Methods COIN was a r and omised controlled trial in patients with previously untreated advanced colorectal cancer . Patients received either continuous oxaliplatin and fluoropyrimidine combination ( arm A ) , continuous chemotherapy plus cetuximab ( arm B ) , or intermittent ( arm C ) chemotherapy . In arms A and B , treatment continued until development of progressive disease , cumulative toxic effects , or the patient chose to stop . In arm C , patients who had not progressed at their 12-week scan started a chemotherapy-free interval until evidence of disease progression , when the same treatment was restarted . R and omisation was done central ly ( via telephone ) by the MRC Clinical Trials Unit using minimisation . Treatment allocation was not masked . The comparison of arms A and B is described in a companion paper . Here , we compare arms A and C , with the primary objective of establishing whether overall survival on intermittent therapy was non-inferior to that on continuous therapy , with a predefined non-inferiority boundary of 1·162 . Intention-to-treat ( ITT ) and per- protocol analyses were done . This trial is registered , IS RCT N27286448 . Findings 1630 patients were r and omly assigned to treatment groups ( 815 to continuous and 815 to intermittent therapy ) . Median survival in the ITT population ( n=815 in both groups ) was 15·8 months ( IQR 9·4–26·1 ) in arm A and 14·4 months ( 8·0–24·7 ) in arm C ( hazard ratio [ HR ] 1·084 , 80 % CI 1·008–1·165 ) . In the per- protocol population ( arm A , n=467 ; arm C , n=511 ) , median survival was 19·6 months ( 13·0–28·1 ) in arm A and 18·0 months ( 12·1–29·3 ) in arm C ( HR 1·087 , 0·986–1·198 ) . The upper limits of CIs for HRs in both analyses were greater than the predefined non-inferiority boundary . Preplanned subgroup analyses in the per- protocol population showed that a raised baseline platelet count , defined as 400 000 per μL or higher ( 271 [ 28 % ] of 978 patients ) , was associated with poor survival  with intermittent chemotherapy : the HR for comparison of arm C and arm A in patients with a normal platelet count was 0·96 ( 95 % CI 0·80–1·15 , p=0·66 ) , versus 1·54 ( 1·17–2·03 , p=0·0018 ) in patients with a raised platelet count ( p=0·0027 for interaction ) . In the per- protocol population , more patients on continuous than on intermittent treatment had grade 3 or worse haematological toxic effects ( 72 [ 15 % ] vs 60 [ 12 % ] ) , whereas nausea and vomiting were more common on intermittent treatment ( 11 [ 2 % ] vs 43 [ 8 % ] ) . Grade 3 or worse peripheral neuropathy ( 126 [ 27 % ] vs 25 [ 5 % ] ) and h and –foot syndrome ( 21 [ 4 % ] vs 15 [ 3 % ] ) were more frequent on continuous than on intermittent treatment . Interpretation Although this trial did not show non-inferiority of intermittent compared with continuous chemotherapy for advanced colorectal cancer in terms of overall survival , chemotherapy-free intervals remain a treatment option for some patients with advanced colorectal cancer , offering reduced time on chemotherapy , reduced cumulative toxic effects , and improved quality of life . Subgroup analyses suggest that patients with normal baseline platelet counts could gain the benefits of intermittent chemotherapy without detriment in survival , whereas those with raised baseline platelet counts have impaired survival and quality of life with intermittent chemotherapy and should not receive a treatment break . Funding Cancer Research UK Background Population -based colorectal cancer screening has been shown to reduce cancer specific mortality and is used across the UK . Despite evidence that older age , male sex and deprivation are associated with an increased incidence of colorectal cancer , uptake of bowel cancer screening varies across demographic groups . The aim of this study was to assess the impact of age , sex and deprivation on outcomes throughout the screening process . Methods A prospect ively maintained data base , encompassing the first screening round of a faecal occult blood test screening programme in a single geographical area , was analysed . Results Overall , 395 096 individuals were invited to screening , 204 139 ( 52 % ) participated and 6 079 ( 3 % ) tested positive . Of the positive tests , 4 625 ( 76 % ) attended for  colonoscopy  and cancer was detected in 396 individuals ( 9 % ) . Lower uptake of screening  was associated with younger age , male sex and deprivation ( all p<0.001 ) . Only deprivation was associated with failure to proceed to colonoscopy  following a positive test ( p<0.001 ) . Despite higher positivity rates in those that were more deprived ( p<0.001 ) , the likelihood of detecting cancer in those attending for colonoscopy was lower ( 8 % most deprived vs 10 % least deprived , p = 0.003 ) . Conclusion Individuals who are deprived are less likely to participate in screening  , less likely to undergo colonoscopy  and less likely to have cancer identified as a result of a positive test . Therefore , this study suggests that strategies aim ed at improving participation of deprived individuals in colorectal cancer screening should be directed at all stages of the screening process and not just uptake of the test PVI 5FU gives increased response rates and reduced toxicity when compared to bolus 5FU ( J Clin Oncol 1989 , 425–432 ) . PVI 5FU administration was reported to give highly variable ( > 1000-fold ) plasma 5FU concentrations at steady state ( FU Css ) which correlated with toxicity ( Ann Oncol 1996 , 47–53 ) ; but only 19 patients were studied . Therefore , we performed a study of  PVI 5FU in 61 patients with advanced colorectal cancer to assess the variability ( inter- and intra-subject ) in 5FU Css associated with PVI 5FU ( 300 mg m−2 day−1 ) and to attempt to correlate pharmacodynamic end-points ( anti-tumour activity , toxicity ) with 5FU Css as a prelude to ‘ exposure-guided ’ 5FU administration . All 5FU sampling was performed between 10 am and noon . PVI 5FU administration continued to 26 weeks in patients with disease improvement or stabilization . The response rate was 26 % ( 33 % stable disease ) and median survival was 11 months . H and –foot syndrome was the most common dose limiting toxicity . Variability in 5FU300Css was considerably less than previously reported ; 94 ± 25 ng ml−1(CV = 27 % ) . No relationships were demonstrated between subject mean 5FU300Css and PD end-points such as response , mucositis , diarrhoea and h and –foot syndrome . The lack of correlation suggests that measurement of 5FU concentrations should not be used to individualize dosing in patients receiving PVI 5FU for advanced colorectal cancer . © 2001 Cancer Research Background The results of R and omized Controlled Trials ( RCTs ) on time-to-event outcomes that are usually reported are median time to events and Cox Hazard Ratio . These do not constitute the sufficient statistics required for meta- analysis or cost-effectiveness analysis , and their use in secondary analyses requires strong assumptions that may not have been adequately tested . In order to enhance the quality of secondary data analyses , we propose a method which derives from the published Kaplan Meier survival curves a close approximation to the original individual patient time-to-event data from which they were generated . Methods We develop an algorithm that maps from digitised curves back to KM data by finding numerical solutions to the inverted KM equations , using where available information on number of events and numbers at risk . The reproducibility and accuracy of survival probabilities , median survival times and hazard ratios based on reconstructed KM data was assessed by comparing published statistics ( survival probabilities , medians and hazard ratios ) with statistics based on repeated reconstru 
    Output:
    
Results My5-FU assays were found to be consistent with reference liquid chromatography t and em mass spectrometry .