***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 There is no conclusive evidence that screening based on serum prostate-specific antigen ( PSA ) tests decreases  prostate-cancer mortality . Since its introduction in the USA around 1990 , uptake of PSA testing has been rapid in the USA , but much less common in the UK . Our aim was to study trends over time in  prostate-cancer mortality and incidence in the USA and UK in 1975 - 2004 , and compare these patterns with trends in screening and treatment . METHODS Joinpoint regression analysis of cancer-mortality statistics from Cancer Research UK ( London , UK ) and from the US National Cancer Institute Surveillance , Epidemiology and End Results ( SEER ) programme from 1975 to 2004 was used to estimate the annual percentage change in prostate-cancer mortality in both countries and the points in time when trends changed . The ratio of USA to UK age-adjusted prostate-cancer incidence was also assessed . FINDINGS Age-specific and age-adjusted prostate-cancer mortality peaked in the early 1990s at almost identical rates in both countries , but age-adjusted mortality in the USA subsequently declined after 1994 by -4.17 % ( 95 % CI -4.34 to -3.99 ) each year , four-times the rate of decline in the UK after 1992 ( -1.14 % [ -1.44 to -0.84 ] ) . The mortality decline in the USA was greatest and most sustained in patients aged 75 years or older ( -5.32 % [ -8.23 to -2.32 ] ) , whereas death rates had plateaued in this age group in the UK by 2000 . The mean ratio of USA to UK age-adjusted prostate-cancer incidence rates in 1975 - 2003 was 2.5 , with a pronounced peak around the time that PSA testing was introduced in the USA . Numbers needed to treat to prevent one death from prostate cancer were 33 000 in the 55 - 64-year age group . INTERPRETATION The striking decline in prostate-cancer mortality in the USA compared with the UK in 1994 - 2004 coincided with much higher uptake of PSA screening in the USA . Explanations for the different trends in mortality include the possibility of an early effect of initial screening rounds on men with more aggressive asymptomatic disease in the USA , different approaches to treatment in the two countries , and bias related to the misattribution of cause of death . Speculation over the role of screening will continue until evidence from r and omised controlled trials is published OBJECTIVE To assess the reasons for the dramatic surge in prostate cancer incidence from 1986 to 1991 . DESIGN Population -based study of incidence rates and procedures used to detect and diagnose prostate cancer derived from Medicare cl aims data and the National Cancer Institute 's Surveillance , Epidemiology , and End Results ( SEER ) program from 1986 to 1991 . SETTING Four SEER areas ( Connecticut ; Atlanta , Ga ; Detroit , Mich ; and Seattle -- Puget Sound , Wash ) covering approximately 6 % of the US population . PARTICIPANTS A 5 % r and om sample of male fee-for-service Medicare beneficiaries aged 65 years and older without cancer , and all men with prostate cancer diagnosed at 65 years of age and older residing in the four areas . MAIN OUTCOME MEASURES The age-adjusted rates of prostate cancer incidence , prostate needle biopsy , transurethral resection of the prostate , serum prostate-specific antigen ( PSA ) testing , and transrectal ultrasound .  RESULTS The age-adjusted incidence rate of prostate cancer among men aged 65 years and older in the four SEER areas rose 82 % from 1986 to 1991 , with the largest annual increases occurring in 1990 ( 20 % ) and 1991 ( 19 % ) . Prostate needle biopsy rates increased while the use of transurethral resection of the prostate declined from 1986 to 1991 . The rising needle biopsy rate has been driven by an exponential increase in PSA testing in the general population from 1988 to 1991 and , to a much lesser extent , the increasing use of transrectal ultrasound since 1986 . The use of PSA or transrectal ultrasound  has increased across age and race groups and in different geographic areas . However , there remain wide geographic variations in the use of PSA screening . CONCLUSIONS The recent dramatic epidemic of prostate cancer is likely the result of the increasing detection of tumors result ing from increased PSA screening . The magnitude and rapidity of the incidence rise suggest that changes in the intensity of medical surveillance is the most plausible explanation for this trend . IMPLICATION S The rapid diffusion of screening interventions that have the ability to detect latent asymptomatic disease leads to important concerns regarding costs and patient quality of life for men aged 65 years and older . Geographic variability in the adoption of PSA testing underscores uncertainty and disagreement about its value for reducing prostate cancer mortality . More research is required to determine the effectiveness of screening for prostate cancer BACKGROUND The neutrophil-lymphocyte ratio ( NLR ) , proposed as an indicator of cancer-related inflammation , has known prognostic value in prostate cancer . We examine its association with survival ( OS ) and response in patients treated with second-line chemotherapy .  METHODS We analysed patients with metastatic castration-resistant prostate cancer ( mCRPC ) treated in the TROPIC trial , evaluating cabazitaxel versus mitoxantrone . Cox regression models were used to investigate the association of baseline NLR ( BLNLR ) with OS and the significance of a change in NLR count with treatment . Logistic regression models were used to determine the association of BLNLR counts with prostate specific antigen ( PSA ) and RECIST responses . The optimal NLR cut-off was established based on the concordance index of different values . RESULTS Data from 755 , 654 and 405 patients was available for OS , PSA and RECIST response analysis respectively . Median OS was 14.0 months [ 95 % confidence interval ( CI ) 13.2 - 14.8 ] . Median NLR was 2.9 ( IQR : 1.9 - 5.1 ) . BLNLR was associated with survival ( HR 1.5 , 95 % CI 1.1 - 2.1 , P = 0.011 ) in multivariable analysis ( MVA ) independently of variables included in the Halabi nomogram , treatment arm and corticosteroid use . The optimal cut-off for a dichotomous NLR was selected at 3.0 based on its higher c-index related to survival . BLNLR ≥3.0 was associated with lower PSA response ( 40.1 % versus 59.9 % ; P < 0.001 ) and RECIST response ( 7.7 % versus 15.6 % , P = 0.022 ) in MVA . Conversion from high ( ≥3 ) to low ( <3 ) NLR was associated with improved survival ( HR 0.66 ; 95 % CI 0.51 - 0.85 ; P = 0.001 ) and higher PSA response rates ( 66.4 % versus 33.6 % ; P = 0.000 ) . Use of corticosteroids at baseline did not modify the association between NLR and survival . CONCLUSIONS NLR is a valid prognostic biomarker in CRPC and is associated with survival , PSA and RECIST responses in patients treated with second-line chemotherapy . Changes in NLR counts with treatment may indicate benefit . NLR prognostic value is independent of prior use of corticosteroids . CLINICAL TRIALSGOV NCT00417079 
    Output:
    
Our results suggest that an elevated NLR might be employed as a prognostic marker of biochemical changes and prognosis to facilitate risk stratification and decision making for individual treatment of PCa patients .