TOPIC: Disorders of the Pleura TYPE: Original Investigations PURPOSE: Onset of a malignant pleural effusion (MPE), whether as a newly diagnosed malignant disease or as progression of an already known malignancy, is an important marker for rapid clinical deterioration. This motivates a need to reassess prognosis, not only to better explain the clinical significance of events to the patient, but also to weigh in on treatment options. The PROMISE Score for MPE predicts a 3-month mortality rate for this population. We assessed the clinical application of the PROMISE score and analyzed predictors of survival in our center. METHODS: Retrospective study including patients with confirmed MPE. PROMISE score was calculated using hemoglobin levels, serum white blood cells count, serum C-Reactive Protein levels, ECOG Performance Status, cancer type and a history of previous chemotherapy and/or radiotherapy. Each patient was assigned a 3-month mortality rate according to their Clinical PROMISE Score: Group 1 (Score: 0-20), <25% mortality; Group 2 (Score: 21-27), 25 to <50% mortality; Group 3 (Score: 28-35), 50 to <75% mortality; and Group 4 (Score: >35), ≥75% mortality. Survival was determined by Kaplan-Meier curves and compared by log-rank test. A multivariate analysis was performed using Cox proportional hazard model. RESULTS: We studied a total of 273 patients, divided as follows according to PROMISE score: Group 1 (n=97), Group 2 (n=95), Group 3 (n=74) and Group 4 (n=7); 50.5% of the patients were male, and mean age at MPE diagnosis was 67.1±12.9 years old. Two-thirds of the patients had an ECOG <2. More than half (57.2%) the patients had a large-volume pleural effusion at the time of diagnosis; lung was the most frequent primary malignancy site (52.7% vs 47.3% non-pulmonary malignancies). Treatment strategies were continued in 64.1% of all patients; a best supportive care strategy was opted for the remaining 35.9%. Overall median survival was 95 (95%CI, 70.6-117.4) days. Median survival was significantly different between PROMISE score risk groups (p<.001): 275 (95%CI, 180.1-369.1) days in Group 1, 95 (95%CI, 70.4-119.6) days in Group 2, 22 (95%CI, 12.6-31.4) days in Group 3 and 10 (95%CI, 4.9-15.1) days in Group 4. After adjusting for age, sex and cancer-treatment, PROMISE score was an independent predictor of survival among patients of all risk groups (Group 2 vs Group 1: HR 2.24 [CI 95%, 1.64-3.06]; Group 3 vs Group 1: HR 4.17 [CI 95%, 2.93-5.95]; Group 4 vs Group 1: HR 7.07 [CI 95%, 3.11-16.08]; p<.001). Mortality rates at the 3-month mark were as follows: 22.7% mortality in Group 1; 47.4% mortality in Group 2; 81.1% mortality in Group 3; and 100% mortality in Group 4. CONCLUSIONS: The PROMISE score demonstrated to be a valuable tool for predicting survival among MPE patients. In respect to 3-month mortality rates, our sample maintained a similar risk stratification as the one originally proposed by the PROMISE score, with a tendency towards the higher thresholds. CLINICAL IMPLICATIONS: Usage of the PROMISE score in the context of newly diagnosed MPE provides an important risk stratification and enables the clinician to better reassess prognosis in this subset of patients. By accurately predicting 3-month mortality rates, its application helps clinicians in the treatment decision process, identifying those patients more likely to benefit from supportive measures alone, such as repeat thoracentesis, rather than definitive treatment options like pleurodesis or tunneled catheter placement. DISCLOSURES: No relevant relationships by Helder Bastos, source=Web Response No relevant relationships by David Coelho, source=Web Response No relevant relationships by maria gabriela fernandes, source=Web Response No relevant relationships by Claudia Freitas, source=Web Response No relevant relationships by maria magalhães, source=Web Response No relevant relationships by Pedro Magalhães Ferreira, source=Web Response No relevant relationships by Beatriz Martins, source=Web Response no disclosure on file for Natália Melo; No relevant relationships by Mariana Serino, source=Web Response No relevant relationships by Rita Trovisco, source=Web Response