Enhancing prognostic precision: exploring the role of lung immune prognostic index in immunotherapy-treated soft tissue sarcoma patients-a retrospective study.

[BACKGROUND] Soft tissue sarcoma (STS), is a rare and heterogeneous malignant mesenchymal tumor that has seen limited therapeutic advances in the past five decades, resulting in limited therapeutic efficacy and a poor prognosis in cases with metastasis or recurrence. The Lung Immune Prognostic Index (LIPI), integrating pretreatment-derived neutrophil-to-lymphocyte ratio (dNLR) and lactate dehydrogenase (LDH), has been associated with adverse outcomes in various cancers. However, its role in STS remains unclear.

[METHODS] The retrospective study collected and analyzed clinical data, including PLR, NLR, dNLR, LDH, LIPI and the combined positive score (CPS) for PD-L1 expression, of 109 STS patients who were diagnosed and treated with immunotherapy at Sichuan University's West China Hospital. We evaluated the prognostic value of pre-treatment PLR, NLR, dNLR, LDH, LIPI and CPS separately in STS patients. The correlation between the LIPI and metastasis was analyzed using the Kaplan-Meier method and Cox regression analysis, reporting hazard ratios (HRs) and 95% confidence intervals (CIs). Univariate and multivariate analyses were conducted to identify the independent risk factors for metastasis. A nomogram model was established using R software (version 4.1.0).

[RESULTS] The area under the curve (AUC) and the best cutoff values were 0.591 and 200.58 for PLR, 0.574 and 2.34 for NLR, 0.635 and 3.01 for dNLR, and 0.559 and 170.5 for LDH, respectively. The LIPI, composed of LDH and dNLR, demonstrated a larger AUC than other hematological factors in the time-dependent receiver operating characteristic (t-ROC) curve. This study enrolled 109 patients with STS, of whom 44 (40.4%), 36 (33.0%), and 29 (26.6%) were classified into three LIPI-based categories: good, intermediate, and poor, respectively. In univariate analysis, tumor metastasis, Eastern Cooperative Oncology Group Performance Status (ECOG PS), CPS, and LIPI were significantly associated with overall survival (OS). Hazard ratios (HRs) for these variables were as follows: tumor metastasis HR = 3.60 (P < 0.001), ECOG PS HR = 2.80 (P < 0.001), CPS HR = 2.29 (P < 0.001), and LIPI HR = 3.50 (P < 0.001). Through multivariate analysis, ECOG PS and LIPI emerged as independent prognostic markers, with HRs of 1.84 (P = 0.004) and 2.12 (P = 0.017), respectively. Finally, a nomogram was constructed by integrating the significant prognostic factors. The concordance index (C-index) was 0.71, and the calibration curve indicated that the nomogram could accurately predict the 3- and 5-year overall survival (OS) of patients with STS.

[CONCLUSION] For patients receiving immunotherapy, the LIPI scoring system-integrating dNLR and LDH demonstrated superior prognostic performance compared to individual biomarkers (PLR, dNLR or LDH alone) in early survival prediction and distant metastasis prognosis assessment. This scoring system may serve as a potential method for clinical prognostic assessment in these patients.