Objectives Explanation about the impending death of imminently dying patients with cancer is important for their families. However, little is known about how clinicians explain impending death and how families perceive the explanation. We aimed to clarify bereaved families’ perception of the need for improvements in the explanation about impending death and to explore the factors contributing to the need.

Methods In a nationwide survey of 818 bereaved families of patients with cancer admitted to inpatient hospices in Japan, we evaluated family-perceived need for improvements in the explanation about impending death and families’ experiences of the explanation.

Results Among all the participants (n=516, 63%), 35 (6.8%), 123 (24%) and 297 (58%) families felt that much/considerable, some and no improvements were needed, respectively. Independent determinants of the need were a younger patient age (OR=0.97; 95% CI 0.95 to 0.99; P=0.009); not receiving an ‘explicit explanation about physical signs of impending death’ (OR=0.67; 95% CI 0.51 to 0.88; P=0.004); not receiving an ‘explanation of how long the patient and family could talk’ (OR=0.67; 95% CI 0.51 to 0.88; P<0.001); receiving an ‘excessive warning of impending death’ (OR=1.45; 95% CI 1.03 to 2.03; P=0.033) and having a feeling of ‘uncertainty caused by vague explanations about future changes’ (OR=1.77; 95% CI 1.38 to 2.27; P<0.001).

Conclusions Nearly a third of the bereaved families perceived some need to improve the explanation about impending death. To better help patients/families prepare for their end-of-life, clinicians should recognise and explain various impending death signs; find a balance between detailed explanation and excessive warning and address how long they could talk in the remaining time.