AIMS AND OBJECTIVES: Appropriately timed cessation of systemic anticancer treatments is an important part of a patient's quality of life (QoL). We aimed to determine the right time to discontinue systemic anticancer therapy (SACT) and switch to the best supportive care for patients with advanced breast cancer (BC) who are nearing the end of life. METHODS: We identified 200 BC patients who died within 30 days after palliative SACT. Laboratory parameters and Eastern Cooperative Oncology Group (ECOG) performance status (PS) were recorded when the patients received their last SACT and at the time of their penultimate treatment. The (Neutrophil-ECOG-LDH-Bilirubin) 'NELBI' score, created on the basis of the optimum cut-off points of ECOG PS, neutrophil count, bilirubin level, and lactate dehydrogenase (LDH) level, which can predict mortality within 30 days after SACT, was scored between 0 and 4. Patients were stratified on the basis of the NELBI score. RESULTS: A total of 4164 patients receiving palliative treatment for advanced BC were examined. A total of 4.8% of patients died within 30 days after SACT. The percentage of patients who died within 30 days after SACT among all deceased patients was 19.4%. The median time from the last systemic treatment to death was 19.5 ± 7.85 (95% CI 18.06-20.26) days, and the median time from the penultimate treatment to death was 43.0 ± 24.65 (95% CI 46.81-53.85) days. A total of 21.3%, 58.0%, 70.7%, and 88.9% of patients with NELBI scores of 0, 1, 2, and 3-4, respectively, died within 30 days after SACT. Compared with a NELBI score of 0, a NELBI score of 1 (OR = 5.095
95% CI 2.654- 9.784
p <
0.001), a NELBI score of 2 (OR = 8.911
95% CI 4.299-18.474
p <
0.001), and a NELBI score of 3-4 (OR = 29.500
95% CI 6.135- 141.847
p <
0.001) was associated with significantly greater 30-day mortality. The AUC of the NELBI scoring for 30-day mortality prediction after SACT was 0.713. CONCLUSIONS: The 'NELBI' scoring system has the potential to significantly improve patient care by guiding the appropriate discontinuation of SACTs in patients with BC.