Objectives To clarify the relationship between Phase of Illness at the time of admission to palliative care units and symptoms of patients with advanced cancer.

Methods This study was a secondary analysis of the East Asian collaborative cross-cultural Study to Elucidate the Dying process. Palliative physicians recorded data, including Phase of Illness, physical function and the Integrated Palliative care Outcome Scale. We used multinomial logistic regression to analyse ORs for factors associated with Phase of Illness. Twenty-three palliative care units in Japan participated from January 2017 to September 2018.

Results In total, 1894 patients were analysed—50.9% were male, mean age was 72.4 (SD±12.3) years, and Phase of Illness at the time of admission to the palliative care unit comprised 177 (8.9%) stable, 579 (29.2%) unstable, 921 (46.4%) deteriorating and 217 (10.9%) terminal phases. Symptoms were most distressing in the terminal phase for all items, followed by deteriorating, unstable and stable (p<0.001). The stable phase had lower association with shortness of breath (OR 0.73, 95% CI 0.57 to 0.94) and felt at peace (OR 0.73, 95% CI 0.56 to 0.90) than the unstable phase. In the deteriorating phase, weakness or lack of energy (OR 1.20, 95% CI 1.02 to 1.40) were higher, while drowsiness (OR 0.82, 95% CI 0.71 to 0.97) and felt at peace (OR 0.81, 95% CI 0.71 to 0.94) were significantly lower.

Conclusion Our study is reflective of the situation in palliative care units in Japan. Future studies should consider the differences in patients’ medical conditions and routinely investigate patients’ Phase of Illness and symptoms.

Trial registrarion number UMIN000025457