Abstract： Background Despite psycho-oncological concerns and studies having thrived these past decades,sparse reports illustrate to what extent Chinese cancer patients are involved and influenced by comorbid mental health problems.To investigate the mental health condition of cancer patient,as well as its possible impacts on prognosis,the first large-scale survey was performed in the west of China.Methods For standardizing and facilitating the assessment of mental illness in inpatients with cancer,a multidisciplinary rating flow was designed and established.On the basis of this system,between May 1st and 31st 2009,2279 cancer inpatients from nine medical centers received preliminarily screening executed by oncologists using screening scales Mental Health Screening Questionnaire (MHSQ),Zung self-rating depression scales (SDS),Zung self-rating anxiety scale (SAS),and posttraumatic stress disorder checklist-civilian version (PCL-C).Further analyses of the ones screened positively were conducted by psychiatrists applying corresponding symptom-rating scales (HAMA/HAMD/BPRS).We summarized the overall proportion of patients with impaired mental health based on the data acquired from preliminary screening,and then calculated occurrence rates of each clinical syndrome of mental disorder according to symptom conclusions.The impact of comorbid mental illness was evaluated through the follow-up scheduled 1 year later,by comparing the survival rate,progression of disease,and quality of life (QoL) between subgroup patients with or without clinical syndrome of mental disorder.Results In preliminary screenings,26.1％ (595/2279) yielded positive results.Further symptom conclusions confirmed 15.8％ (359/2279) with clinical syndrome of mental disorder.Regarding specific type of syndrome,the occurrence rates of depression,anxiety,psychotic symptoms,and stress-related disorders were 13.3％,10.2％,2.8％,and 1.4％,respectively.Follow-up assessments were successfully performed in 1918 subjects (84.2％).Further analyses indicated that although insignificant influence was observed in terms of 1-year survival rate and disease progression,cancer patients with a clinical syndrome of mental disorder obtained significantly lower levels (P ＜0.05) in five domains of QoL (scored by QLQ-C30).Conclusion In China,at least 26％ of cancer patients experienced impaired mental health,of which 60％ already had a detectable clinical syndrome of mental disorder,which could significantly undermine their QoL.