Screening for untreated depression in cancer patients: a Japanese experience. 
Guidelines for supportive care in cancer patients have recommended routine psychological screening in clinical practice, and a Japanese national project has recommended screening for depression using the Distress and Impact Thermometer.  However, a previous study advocating the validity of the Distress and Impact Thermometer may have overestimated its effectiveness, as the study included already-treated patients who were not screening targets.  This study re-evaluated the performance and usefulness of the Distress and Impact Thermometer using an adequate sample size and appropriate study design.  Patients were consecutively recruited at two highly specialized hospitals and three university hospitals in Japan.  Inclusion criteria were (i) undergoing aggressive anti-cancer treatment, (ii) the Eastern Cooperative Oncology Group performance status score <3 and (iii) age >20 years.  Patients who were receiving psychiatric treatment were excluded from the study.  After completing the Distress and Impact Thermometer, patients were evaluated with the gold-standard Composite International Diagnostic Interview by researchers who were blinded to the patients' Distress and Impact Thermometer scores.  Forty-four patients (9%) who were receiving psychiatric treatment were excluded.  Of 468 subjects included in the final analysis, only 3 had current depression (0.6%).  Using cutoff points recommended by the previous study, the positive and negative predictive values were 0.02 and 0.99, respectively.  Our data indicated that screening for untreated depression in cancer patients was not useful in the specific clinical settings that were studied, and such screening should be implemented in appropriate contexts.  Since there are no evidence-based recommendations regarding contexts in which psychological screening is essential, further research is needed.