Open AccessArticle Real-World 30-Day Mortality After the Last Dose of Immune Checkpoint Inhibitors: A Multicenter Retrospective Cohort Study in Turkey by Kadriye Başkurt Kadriye Başkurt Scilit Preprints.org Google Scholar 1,*, Orhun Akdoğan Orhun Akdoğan Scilit Preprints.org Google Scholar 2, Yasemin Sağdıç Karateke Yasemin Sağdıç Karateke Scilit Preprints.org Google Scholar 3, İlknur Deliktaş Onur İlknur Deliktaş Onur Scilit Preprints.org Google Scholar 4, Galip Can Uyar Galip Can Uyar Scilit Preprints.org Google Scholar 1, Enes Yeşilbaş Enes Yeşilbaş Scilit Preprints.org Google Scholar 1, Ozan Yazıcı Ozan Yazıcı Scilit Preprints.org Google Scholar 2, Bülent Yıldız Bülent Yıldız Scilit Preprints.org Google Scholar 3, Cengiz Karaçin Cengiz Karaçin Scilit Preprints.org Google Scholar 4, Ömür Berna Çakmak Öksüzoğlu Ömür Berna Çakmak Öksüzoğlu Scilit Preprints.org Google Scholar 1 and Osman Sütçüoğlu Osman Sütçüoğlu Scilit Preprints.org Google Scholar 2 1 Department of Medical Oncology, Ankara Etlik City Hospital, 06170 Ankara, Turkey 2 Department of Medical Oncology, Gazi University School of Medicine, 06500 Ankara, Turkey 3 Department of Medical Oncology, Eskişehir Osmangazi University School of Medicine, 26040 Eskişehir, Turkey 4 Department of Medical Oncology, Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital, 06200 Ankara, Turkey * Author to whom correspondence should be addressed. Curr. Oncol. 2026, 33(6), 340; https://doi.org/10.3390/curroncol33060340 (registering DOI) Submission received: 17 May 2026 / Accepted: 3 June 2026 / Published: 6 June 2026 Simple Summary Immunotherapy has improved outcomes for many cancer patients, but not all patients benefit equally. In some cases, treatment is continued very close to the end of life, when the likelihood of benefit is low. This study examined how often patients died within 30 days after their last dose of immunotherapy and which clinical factors were associated with this early mortality. We analyzed real-world data from multiple oncology centers and found that a significant proportion of patients died within this short time period. Poor performance status was the strongest factor linked to early death, while age, cancer type, and treatment characteristics were not clearly associated. These findings highlight the importance of careful patient selection and timely decision-making when continuing or stopping immunotherapy. Better identification of patients unlikely to benefit may help avoid unnecessary treatment and support earlier integration of palliative care. Abstract Short-term mortality following the last dose of immune checkpoint inhibitors (ICIs) is an increasingly recognized real-world outcome measure, yet its clinical predictors remain poorly characterized. This multicenter retrospective study included 458 consecutive patients with advanced melanoma, non-small cell lung cancer, or renal cell carcinoma who received ICIs at four tertiary centers in Turkey between 2018 and 2023. The primary endpoint was 30-day mortality after the final ICI dose. Among 458 patients, 71 (15.5%) died within 30 days. Multivariable logistic regression identified ECOG performance status ≥ 2, number of metastatic sites ≥ 3, and log-transformed C-reactive protein-to-albumin ratio (log-CAR) as independent predictors of 30-day mortality in Model 1 (AUC 0.954), while ECOG PS ≥ 2, brain metastasis, metastatic sites ≥ 3, and log-NLR were independent predictors in Model 2 (AUC 0.912). In the lung cancer subgroup, log-CAR and NLR remained independent predictors while ECOG PS did not. Patients who died within 30 days had significantly shorter progression-free survival (1.18 vs. 4.63 months) and overall survival (2.30 vs. 14.39 months) compared with survivors. These findings suggest that routine assessment of inflammatory and nutritional biomarkers alongside tumor burden parameters may help identify patients at high risk of early mortality and inform the timing of supportive care in ICI-treated populations. 1. Introduction Inflammatory and nutritional markers derived from routine blood tests have been evaluated as prognostic tools in ICI-treated patients. The neutrophil-to-lymphocyte ratio (NLR), which reflects the balance between innate immune activation and adaptive immune function, has been associated with worse overall survival and progression-free survival across multiple tumor types receiving ICIs [ 9]. The C-reactive protein-to-albumin ratio (CAR), which integrates systemic inflammation and nutritional reserve into a single index, has similarly shown consistent prognostic value in this setting [ 10]. Despite their established role in predicting survival outcomes, whether these markers are independently associated with early mortality following the last ICI dose has not been examined in a real-world multicenter cohort. The objective of this multi-center retrospective study was to describe real-world 30-day mortality after the last dose of ICIs and to identify demographic and clinical characteristics associated with short-term mortality in patients treated for advanced melanoma, non-small cell lung cancer, and renal cell carcinoma. 2. Materials and Methods 2.1. Study Design and Patient Cohort This multi-center retrospective study included all consecutive patients who received immune checkpoint inhibitors (ICIs) at four tertiary oncology centers in Turkey between 1 January 2018 and 30 December 2023. Eligible tumor types were metastatic melanoma, non–small cell lung cancer (NSCLC), and renal cell carcinoma (RCC). Patients participating in interventional clinical trials were excluded. A STROBE-compliant flow diagram ( Figure 1) outlines the total number of screened patients, the number excluded due to missing treatment or survival data, and the final study cohort of 458 patients. 2.2. Data Collection and Variables Data were extracted from electronic medical records and oncology clinic archives. Collected variables included demographic characteristics (age, sex, smoking status); cancer-related information (tumor type, stage, and sites of metastasis including brain and liver involvement, and number of metastatic sites); treatment characteristics (ICI agent, line of therapy (first-line vs. second-line and beyond), and treatment regimen (monotherapy vs. combination)); treatment intent (curative vs. palliative); and performance status based on the Eastern Cooperative Oncology Group (ECOG) scale. Comorbidity burden was quantified using the modified Charlson Comorbidity Index (mCCI), dichotomized as 5.0 due to critical multicollinearity with both the number of metastatic sites (tumor burden) and log-CAR (systemic inflammation). Consequently, to prevent variance inflation and preserve model stability, LDH was excluded from the multivariable steps. Multivariate Cox Proportional Hazards Regression Analyses for Progression-Free Survival (PFS) and Overall Survival (OS) from ICI Initiation. Multivariate Cox Proportional Hazards Regression Analyses for Progression-Free Survival (PFS) and Overall Survival (OS) from ICI Initiation. Predictor Variables Model A (log-CAR) Hazard Ratio (95% CI) Model A (log-CAR) p-Value Model B (log-NLR) Hazard Ratio (95% CI) Model B (log-NLR) p-Value Progression-Free Survival (PFS) Age (≥65 vs. 5.0 due to critical multicollinearity with both the number of metastatic sites (tumor burden) and log-CAR (systemic inflammation). Consequently, to prevent variance inflation and preserve model stability, LDH was excluded from the multivariable Cox regression steps. Model Performance and Comparison: The predictive accuracy and goodness-of-fit of the multivariate Cox regression models were evaluated using Harrell’s C-index and the Akaike Information Criterion (AIC), respectively. For Overall Survival (OS), Model A (incorporating log-CAR) demonstrated strong discrimination and superior model fit (C-index: 0.733, AIC: 3159.22) compared to Model B (incorporating log-NLR) (C-index: 0.728, AIC: 3164.26). Similarly, for Progression-Free Survival (PFS), Model A exhibited better predictive performance (C-index: 0.675, AIC: 4044.46) than Model B (C-index: 0.673, AIC: 4053.55). Causes of 30-Day Mortality After the Last Dose of ICI Therapy. Causes of 30-Day Mortality After the Last Dose of ICI Therapy. Causes of Mortality n = 71 % Sepsis/Infection 23 32.4 Disease Progression 21 29.6 Thromboembolic event 14 19.7 Unknown/Not available 6 8.5 Myocardial infarction 5 7.0 Immunotherapy-related toxicity 2 2.8 Note: The specific cause of mortality for 6 patients could not be definitively determined as these events occurred out-of-hospital (at home). 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Oncol. 2026, 33, 340. https://doi.org/10.3390/curroncol33060340 AMA Style Başkurt K, Akdoğan O, Sağdıç Karateke Y, Deliktaş Onur İ, Uyar GC, Yeşilbaş E, Yazıcı O, Yıldız B, Karaçin C, Çakmak Öksüzoğlu ÖB, et al. Real-World 30-Day Mortality After the Last Dose of Immune Checkpoint Inhibitors: A Multicenter Retrospective Cohort Study in Turkey. Current Oncology. 2026; 33(6):340. https://doi.org/10.3390/curroncol33060340 Chicago/Turabian Style Başkurt, Kadriye, Orhun Akdoğan, Yasemin Sağdıç Karateke, İlknur Deliktaş Onur, Galip Can Uyar, Enes Yeşilbaş, Ozan Yazıcı, Bülent Yıldız, Cengiz Karaçin, Ömür Berna Çakmak Öksüzoğlu, and et al. 2026. "Real-World 30-Day Mortality After the Last Dose of Immune Checkpoint Inhibitors: A Multicenter Retrospective Cohort Study in Turkey" Current Oncology 33, no. 6: 340. https://doi.org/10.3390/curroncol33060340 APA Style Başkurt, K., Akdoğan, O., Sağdıç Karateke, Y., Deliktaş Onur, İ., Uyar, G. C., Yeşilbaş, E., Yazıcı, O., Yıldız, B., Karaçin, C., Çakmak Öksüzoğlu, Ö. B., & Sütçüoğlu, O. (2026). Real-World 30-Day Mortality After the Last Dose of Immune Checkpoint Inhibitors: A Multicenter Retrospective Cohort Study in Turkey. Current Oncology, 33(6), 340. https://doi.org/10.3390/curroncol33060340 Article Metrics Article metric data becomes available approximately 24 hours after publication online.
