***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: We previously reported that the Charlson Comorbidity Index ( CCI ) was useful for predicting outcomes in patients undergoing allogeneic hematopoietic cell transplantation ( HCT ) . However , the sample size of patients with scores of 1 or more , captured by the CCI , did not exceed 35 % . Further , some comorbidities were rarely found among patients who underwent HCT . Therefore , the current study was design ed to ( 1 ) better define previously identified comorbidities using pretransplant laboratory data , ( 2 ) investigate additional HCT-related comorbidities , and ( 3 ) establish comorbidity scores that were suited for HCT . Data were collected from 1055 patients , and then r and omly divided into training and validation sets . Weights were assigned to individual comorbidities according to their prognostic significance in Cox proportional hazard models . The new index was then vali date d. The new index proved to be more sensitive than the CCI since it captured 62 % of patients with scores more than 0 compared with 12 % , respectively . Further , the new index showed better survival prediction than the CCI ( likelihood ratio of 23.7 versus 7.1 and c statistics of 0.661 versus 0.561 , respectively , P < .001 ) . In conclusion , the new simple index provided valid and reliable scoring of pretransplant comorbidities that predicted nonrelapse mortality and survival . This index will be useful for clinical trials and patient counseling before HCT Chemotherapy is associated with toxicity in elderly patients with potentially curable malignancies , posing the dilemma of whether to intensify therapy , thereby improving the cure rate , or de-escalate therapy , thereby reducing toxicity , with consequent risks for under- or overtreatment . Adequate tools to define doses and combinations have not been identified for lymphoma patients . We conducted a prospect i ve trial aim ed to evaluate the feasibility and efficacy of chemotherapy modulated according to a modified comprehensive geriatric assessment ( CGA ) in elderly ( aged ≥70 years ) patients with diffuse large B-cell lymphoma ( DLBCL ) . In June 2000 to March 2006 , 100 patients were stratified using a CGA into three groups ( fit , unfit , and frail ) , and they received a rituximab plus cyclophosphamide , doxorubicin , vincristine , and prednisone modulated in dose and drugs according to comorbidities and activities of daily living ( ADL ) and instrumental ADL scores . Treatment was associated with a complete response rate of 81 % and mild toxicity : grade 4 neutropenia in 14 % , anemia in 1 % , and neurological and cardiac toxicity in 2 % of patients . At a median follow-up of 64 months , 51 patients were alive , with 5-year disease-free , overall , and cause-specific survival rates of 80 % , 60 % , and 74 % , respectively . Chemoimmunotherapy adjustments based on a CGA are associated with manageable toxicity and excellent outcomes in elderly patients with DLBCL . Wide use of this CGA-driven treatment may result in better cure rates , especially in fit and unfit patients The objective of this study was to develop a prospect ively applicable method for classifying comorbid conditions which might alter the risk of mortality for use in longitudinal studies . A weighted index that takes into account the number and the seriousness of comorbid disease was developed in a cohort of 559 medical patients . The 1-yr mortality rates for the different scores were : " 0 " , 12 % ( 181 ) ; " 1 - 2 " , 26 % ( 225 ) ; " 3 - 4 " , 52 % ( 71 ) ; and " greater than or equal to 5 " , 85 % ( 82 ) . The index was tested for its ability to predict risk of death from comorbid disease in the second cohort of 685 patients during a 10-yr follow-up . The percent of patients who died of comorbid disease for the different scores were : " 0 " , 8 % ( 588 ) ; " 1 " , 25 % ( 54 ) ; " 2 " , 48 % ( 25 ) ; " greater than or equal to 3 " , 59 % ( 18 ) . With each increased level of the comorbidity index , there were stepwise increases in the cumulative mortality attributable to comorbid disease ( log rank chi 2 = 165 ; p less than 0.0001 ) . In this longer follow-up , age was also a predictor of mortality ( p less than 0.001 ) . The new index performed similarly to a previous system devised by Kaplan and Feinstein . The method of classifying comorbidity provides a simple , readily applicable and valid method of estimating risk of death from comorbid disease for use in longitudinal studies . Further work in larger population s is still required to refine the approach because the number of patients with any given condition in this study was relatively small CONTEXT Patients with cancer often have other medical ailments , referred to as comorbidity . Comorbidity may impact treatment decision-making , prognosis , and quality of care assessment . OBJECTIVE To assess whether comorbidity information can provide important prognostic information in a hospital-based cancer registry . DESIGN , SETTING , AND PARTICIPANTS An observational prospect i ve cohort study using comorbidity data collected by trained hospital-based cancer registrars . Comorbidity was obtained through medical record review using the Adult Comorbidity Evaluation 27 , a vali date d chart-based comorbidity instrument . A total of 17,712 patients receiving care between January 1 , 1995 , and January 31 , 2001 , for the primary diagnosis of new cancer of the prostate , lung ( nonsmall cell ) , breast , digestive system , gynecological , urinary system , or head and neck were included . MAIN OUTCOME MEASURE Duration in months of overall survival . RESULTS A total of 19,268 patients were included in the study ; median duration of follow-up was 31 months . Of these patients , 1556 ( 8.0 % ) were excluded due to missing or unknown data . Severity of comorbidity strongly influenced survival in a dose-dependent fashion and the impact of comorbidity was independent of cancer stage . Compared with patients without comorbidity , the adjusted hazard ratio associated with mild comorbidity was 1.21 ( 95 % confidence interval [ CI ] , 1.13 - 1.30 ) , moderate comorbidity was 1.86 ( 95 % CI , 1.73 - 2.00 ) , and severe comorbidity was 2.56 ( 95 % CI , 2.35 - 2.81 ) . Adjusted Kaplan-Meier survival curves revealed that at any point in time the patients with more severe levels of comorbidity had worse survival ( partial chi2(3 ) due to comorbidity , 523.54 ; P<.001 ) . Model discrimination ranged from 0.71 for head and neck to 0.86 for prostate cancers . CONCLUSIONS Comorbidity is an important independent prognostic factor for patients with cancer . The inclusion of comorbidity in hospital-based cancer registries will increase the value and use of observational research High-dose chemotherapy followed by autologous peripheral blood stem cell transplantation is a widely applied treatment for advanced non-Hodgkin lymphoma ( NHL ) , but few studies have analyzed the tolerability and outcomes in older patients compared with younger patients treated in a homogeneous manner . We retrospectively review ed 152 consecutive patients who underwent autologous stem cell transplantation ( ASCT ) following BEAM conditioning ( carmustine , etoposide , cytarabine , and melphalan ) for NHL from January 2000 through August 2004 at our institution . We compared 59 patients age > or = 60 years and 93 patients age < 60 years . Supportive care was identical for all patients . The frequency of comorbidities was similar between both groups . CD34 + cell doses , days to neutrophil recovery , and days to platelet count > 20,000/mm3 were similar in younger and older patients , although days to platelet count > 50,000/mm3 were longer in the older patients ( median 30.0 days versus 22.5 days , P = .01 ) . Patients over the age of 60 were more likely to develop grade III/IV mucositis than their younger counterparts ( 37.7 % versus17.4 % , P = .0063 ) . Otherwise , the frequency of other grade III/IV toxicities were similar between younger and older patients . Treatment-related mortality ( TRM ) was similar between older and younger patients ( 8.5 % versus 5.4 % , P = .45 ) . Although age was not associated with TRM , the Charlson Comorbidity Index Score was significantly correlated with TRM ( P = .03 ) . Median disease-free survival was similar between older and younger patients ( 21.8 months versus 29.9 months , P = .93 ) , as was overall survival ( OS ) ( 47.7 months versus 62.5 months , P = .20 ) . After controlling for age , the Charlson Comorbidity Index Score influenced OS [ P = .013 ] . Overall , our cohort of patients with NHL over the age of 60 who underwent ASCT following BEAM conditioning experienced toxicities and survival similar to their younger counterparts . Comorbidities significantly influenced TRM and OS in this retrospective cohort . Future study should focus on improving tolerability of conditioning and careful prospect i ve evaluation of comorbidities and their association with outcomes Over 60 % of patients aged over 70 years , diagnosed with non‐Hodgkin 's lymphoma ( NHL ) in the Netherl and s have serious comorbidity . We studied the independent influence of comorbidity on choice of treatment , dose reductions , treatment‐related toxicity and prognosis , using data from a r and om sample of 381 patients from the population ‐based Eindhoven Cancer Registry . About 45 % of patients over 60 years of age with NHL had high impact comorbidity at the time of cancer diagnosis . The proportion of patients with aggressive NHL who received chemotherapy  decreased from 85 % in patients aged 40–60 years to 70 % in those over 60 years . About 65 % of systematic ally treated patients with aggressive NHL suffered from treatment‐related toxicity . Toxicity appeared to be more common among females and those with high‐intermediate or high International Prognostic Index ( IPI ) risk . Among patients with aggressive NHL , the chance of dying for those with high impact comorbidity was twice as high compared with those without comorbidity . This was independent of the IPI risk . Dose reductions are frequently unavoidable for patients with severe comorbidity , poor performance status or chemotherapy‐related toxicity . Whether the less frequent prescription of ( full dose ) chemotherapy for patients with advanced age and /or with comorbidity is justified remains a question for debate Data on outcome , prognostic factors , and treatment for very elderly non‐Hodgkin lymphomas ( NHL ) is sparse . We conducted a multicentre retrospective analysis of NHL patients ≥80 years ( at diagnosis ) treated between 1999 and 2009 . Detailed characteristics were obtained including geriatric syndromes , activities of daily living ( ADLs ) , and co‐morbidities using the Cumulative Illness Rating Scale‐Geriatrics ( CIRS‐G ) . We identified 303 patients : 170 aggressive NHL ( 84 % B cell/16 % T cell ) and 133 indolent NHL ( 82 % B cell/18 % T cell ) . Median age was 84 years ( 80–95 ) .  A geriatric syndrome was present in 26 % of patients , 18 % had ≥1 grade 4 CIRS‐G , and 14 % had loss of ADLs . At 49‐month median follow‐up , 4‐year progression‐free ( PFS ) and overall survival ( OS ) for aggressive NHLs were 31 % and 44 % respectively ( stage I/II : PFS 53 % and OS 66 % ; stage III/IV : PFS 20 % and OS 32 % ; P < 0·0001 and 0·0002 , respectively ) . Four‐year PFS and OS for indolent NHL were 44 % and 66 % respectively , regardless of stage . Multivariate regression analysis identified two key factors that predicted inferior PFS and OS for both NHL groups : lack of CR and loss of ADLs . Prospect i ve studies for very elderly NHL that incorporate geriatric tools , especially ADLs , are warranted PURPOSE The treatment of patients with diffuse large B-cell lymphoma ( DLBCL ) with cardiac comorbidity is problematic , because this group may not be able to receive anthracycline-containing chemoimmunotherapy . We design ed a single-arm phase II multicenter trial of rituximab , gemcitabine , cyclophosphamide , vincristine , and prednisolone ( R-GCVP ) in patients considered unfit for anthracycline-containing chemoimmunotherapy because of cardiac comorbidity . PATIENTS AND METHODS Sixty-one of 62 patients received R-GCVP  , administered on day 1 with gemcitabine repeated on day 8 of a 21-day cycle . Median age was 76.5 years . All patients had advanced disease ; 27 ( 43.5 % ) had left ventricular ejection fraction of ≤ 50 % , and 35 ( 56.5 % ) had an ejection fraction of > 50 % and comorb 
    Output:
    
The majority of studies demonstrated significant impact of comorbidity on survival , reporting poorer survival rates for patients with comorbidities compared to those with no comorbidities .