Malignant pleural effusion (MPE) occurs in approximately 10–15% of patients with advanced cancers, most frequently lung and breast carcinoma (1,2). Its presence generally signifies disseminated disease and limited life expectancy, often ranging from 3 to 12 months (3,4). Prognostic scoring systems have been developed to guide therapeutic approaches, balancing aggressive interventions against palliative care (5,6). The LENT score incorporates lactate dehydrogenase (LDH), ECOG performance status, neutrophil-to-lymphocyte ratio (NLR), and tumor type (9). In contrast, the PROMISE score combines clinical and laboratory parameters to categorize patients into mortality risk strata (10). Although both models have shown clinical utility, their comparative performance, particularly across heterogeneous cancer subtypes, remains an area of ongoing research (11–13). This study aimed to evaluate the prognostic performance of the LENT and PROMISE scores in predicting survival among patients with MPE in an Indian tertiary care population.

Study Design and Population We conducted a retrospective cohort study of patients diagnosed with MPE at a tertiary care hospital of western Rajasthan, between January 2021 and December 2024. Inclusion criteria were: 1. Age ≥18 years 2. Cytological or histological confirmation of MPE 3. Availability of complete laboratory and clinical data Exclusion criteria include suspected but unconfirmed MPE and inadequate clinical records. Data Collection We collected data on patients’ demographic details such as age, sex, smoking status, occupation etc. Furthermore, data on primary tumor type, prior therapy (chemotherapy/radiotherapy), ECOG performance, laboratory parameters like hemoglobin, WBC counts, CRP, and pleural fluid LDH were extracted from records. Scoring • LENT score was calculated as per published criteria (9), categorizing patients into low (0–1), moderate (2–4), and high risk (5–7). • Clinical PROMISE score was applied, stratifying patients into Categories A, B, C or D (10). Outcomes and Statistical Analysis The statistical analysis was done using SPSS software version 21 (SPSS Inc. Chicago, IL, USA). The categorical data were expressed as frequencies and percentages while continuous data were expressed as median and IQR. Overall survival was measured from diagnosis of MPE until death or last follow-up. Survival distributions were analysed using Kaplan–Meier estimates. Cox regression was used to assess predictors of mortality. Statistical significance was set at p<0.05.

Out of 156 screened records of the patients, 142 were included for the final analysis after applying inclusion and exclusion criteria. Median age was 62 years, with 85 (60%) males and 57 (40%) females. We were able to retrieve smoking record of only 90 patients whom 61 patients (68%) were ever-smoker and 29 (32%) were non-smoker. Primary malignancies included lung (102, 72%), breast (16, 11%), mesothelioma (12, 8%), gynaecological (5, 3.5%) & gastrointestinal and others (7, 5%) (Table 1). Table 1. Baseline Characteristics of Patients (n = 142) Variables Distribution N, % Age Median (IQR) 62 (54-70) Sex Male Female 85 (59.9) 57 (40.1) Smoking (n=90) Ever smoker Non-smoker 61 (67.8) 29 (32.2) Primary cancer Lung carcinoma Breast cancer Mesothelioma Gynaecological Gastrointestinal/haematological/ Renal 102 (71.8) 16 (11.3) 12 (8.5) 5 (3.5) 7 (5.0) Previous treatment Chemotherapy Radiotherapy 88 (62.0) 48 (33.8) Timing of pleural effusion At the time of diagnosis On follow up 105 (73.9) 37 (26.1) ECOG performance Good (0-1) Fair (2) Poor (3-4) 36 (25.4) 40 (28.2) 66 (46.4) PROMISE categories A B C D 48 44 36 14 33.8 31.0 25.4 9.8 Pleural effusion was present in 105 (74%) patients at the time of the diagnosis of malignancy whereas 48 patients (34%) developed effusion during the course of the disease. As per the record, 88 patients (62%) had received chemotherapy whereas 48 patients (34%) received radiotherapy for their illness. In terms of ECOG performance status, 76 patients (54%) had score 0-2 whereas 66 patients (46%) had score 3-4. In survival analysis, the median overall survival was 6 months (95% CI: 4.5-7.5). Further, ECOG 3–4 patients had median survival of 2 months versus 10 months for ECOG 0–2 (p<0.001). Prognostic score performance: LENT score: Low risk (n=15), intermediate risk (n=47) and high risk (n=80) patients had had median survival of approximately 11 months, 5 months and 3 months, respectively (table 2). PROMISE score: Data on the distribution of the patients has been displayed in the table 2. Patients were categorised in group A, B, C or D. Group A, B, C and D constitute 48 patients (34%), 44 patient (36%), 31 patients (25%) and 14 patients (10%), respectively. Their median overall survival was 13, 5, 2, 1 month, respectively. Table 2: Survival outcome by LENT risk group LENT group Patients, (n) Median survival (months) 6-months survival (%) 12-months survival (%) Deaths (n) Low risk (0-1) 15 10.9 80.0 46.7 12 Intermediate risk (2-4) 47 4.9 44.7 27.7 45 High risk (5-7) 80 3.0 32.5 10.0 80 Table 3: PROMISE score category and overall survival PROMISE group Patients, n (%) Median overall survival (months) IQR Mortality at 6 months (%) Mortality at 12 months (%) A 48 (33.8) 13 10-16 42.0 74.0 B 44 (31.0) 5 3-7 61.4 86.4 C 36 (25.4) 2 1-3 83.3 91.7 D 14 (9.8) 1 0.5-2 100.0 100.0

Patients with malignant pleural effusion tends to have limited overall survival. The utility of the prognostic tools in such cases is the utmost need so that it can be decided that which patient needed more aggressive treatment. Further, by segregating the patients in this way, the overall cost of the treatment could also be optimised. To predict the survival in cases of malignant pleural effusion, Clive et al developed the LENT score (9). It includes pleural fluid LDH, ECOG performance status, neutrophil to lymphocyte ratio and tumour type. As different tumours has variation in the response to chemotherapy, the role of LENT score became limited (12). To overcome these issues, Psallidas et al developed a new score (PROMISE score) using more comprehensive data (10). It additionally includes chemotherapy and radiotherapy apart from laboratory data that definitely alter the overall survival. Our study demonstrates that both LENT and PROMISE scores are valuable prognostic tools for MPE, but the PROMISE model shows superior predictive accuracy across varying time points (9,10). The LENT score stratifies patients effectively at baseline but underestimates risk beyond short-term survival, consistent with previous literature (6,12). The strong prognostic impact of ECOG status highlights the need to integrate functional assessment into treatment decisions (7). PROMISE, by incorporating multiple clinical and laboratory parameters, provides a more accurate risk assessment and may facilitate better selection of patients for interventions such as pleurodesis or systemic therapy (10,13). There are few limitations to the present study. Firstly, the present study is retrospective in nature. Secondly, we did not have biomarker-based PROMISE scoring due to resource constraints.

The PROMISE score provides superior and consistent prognostic accuracy compared to the LENT score in patients with MPE. Incorporating PROMISE into routine practice may improve individualized care and decision-making for this high-risk population

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