Major depression is a well-documented risk factor for suicide in cancer pat
ients as well as in the general population. However there are no data expla
ining why some cancer patients suffering from major depression have suicida
l ideation, while others do not. The authors investigated the background di
fferences among cancer patients suffering from major depression with and wi
thout suicidal ideation by analyzing the consultation data of patients refe
rred to the psychiatry division. Among the 1,721 referred patients, 220 (12
.8%) were diagnosed with major depression, and of these 113 (51.4%) had sui
cidal ideation. Logistic regression analysis indicated that poor physical f
unctioning and severe depression were significant risk factors. These preli
minary findings suggest that the severity of major depression and physical
functioning are important indicators of suicidal ideation among cancer pati
ents.