Real-world analysis in patients with limited-stage small-cell lung cancer who received durvalumab after concurrent chemoradiotherapy

Introduction

Small-cell lung cancer (SCLC) accounts for approximately 13–15% of all lung cancer cases and is characterized by rapid tumor proliferation, early systemic dissemination, and a strong etiologic association with tobacco exposure. Despite high initial response rates to platinum-based chemotherapy combined with radiotherapy, most patients experience disease relapse within a short period, resulting in a poor overall prognosis. The median survival time ranges from 7 to 12 months for patients with extensive-stage SCLC and 15 to 30 months for those with limited-stage SCLC (LS-SCLC).

For patients with LS-SCLC, the standard frontline treatment is platinum-etoposide-based concurrent chemoradiotherapy (cCRT), with thoracic radiotherapy typically delivered as either a once-daily regimen (60–66 Gy) or a twice-daily regimen (45 Gy). Among patients who achieve a clinical response to initial therapy, sequential prophylactic cranial irradiation (PCI) further reduces the risk of brain metastases and improves overall survival (OS) (1). However, survival outcomes have plateaued over the past three decades, with only modest improvements observed despite optimization of radiotherapy fractionation schedules (2). Recent evidence indicates that higher doses of thoracic radiotherapy, such as hyperfractionated regimens, may enhance local tumor control and improve survival; yet disease relapse rates remain unacceptably high (3).

Immunotherapy targeting immune checkpoints has revolutionized the management of multiple malignancies, including non-small-cell lung cancer (NSCLC) and melanoma (4). Programmed cell death ligand 1 (PD-L1) is frequently expressed in SCLC tissues and contributes to tumor immune evasion, providing a strong rationale for incorporating PD-1/PD-L1 inhibitors into SCLC treatment strategies (5). Preclinical and clinical studies have demonstrated that radiotherapy can synergize with immunotherapy by enhancing tumor antigen presentation and promoting T-cell infiltration into the tumor microenvironment (6).

Durvalumab, a humanized anti-PD-L1 monoclonal antibody, has demonstrated robust efficacy as consolidation therapy after cCRT in patients with unresectable stage III NSCLC, establishing a new standard of care for this disease (7). Recently, the phase III ADRIATIC trial showed that durvalumab consolidation significantly improved both progression-free survival (PFS) and OS compared with placebo in patients with LS-SCLC who had no disease progression after cCRT. The median OS was extended from 33.4 months in the placebo arm to 55.9 months in the durvalumab arm [hazard ratio (HR) 0.73; 95% confidence interval (CI): 0.57–0.93], and the median PFS was increased from 9.2 months in the placebo arm to 16.6 months in the durvalumab arm (HR 0.76; 95% CI 0.61–0.95) (8). These findings represent the first substantial therapeutic advance in LS-SCLC in decades and highlight the potential of immunotherapy to reshape the treatment paradigm for this aggressive malignancy.

Nevertheless, real-world evidence regarding durvalumab consolidation in patients with LS-SCLC remains limited. Randomized controlled trials (RCTs) are conducted in highly selected patient populations and under strictly standardized treatment protocols, which may not fully reflect treatment outcomes in routine clinical practice. In addition, the potential influence of different radiotherapy regimens—particularly hyperfractionated high-dose schedules—on the efficacy of durvalumab has not been well characterized. Furthermore, disease recurrence patterns and optimal subsequent treatment strategies following durvalumab consolidation remain poorly understood. To address these knowledge gaps, the present study retrospectively evaluates the real-world effectiveness and safety of durvalumab consolidation after cCRT in patients with LS-SCLC, with a specific focus on comparing clinical outcomes across different radiotherapy regimens, characterizing disease recurrence patterns, and documenting subsequent lines of therapy. By integrating clinical efficacy, safety, and treatment trajectory data from a real-world cohort, this study aims to complement evidence from pivotal RCTs and provide a more comprehensive understanding of how durvalumab consolidation can be optimized for patients with LS-SCLC in everyday clinical practice. We present this article in accordance with the STROBE reporting checklist (available at https://tlcr.amegroups.com/article/view/10.21037/tlcr-2026-0287/rc).

Methods

This retrospective, single-center, real-world cohort study was conducted at Peking University Cancer Hospital to evaluate the clinical effectiveness and safety of durvalumab consolidation following cCRT in patients with LS-SCLC. Eligible patients were aged 18 years or older, had histologically or cytologically confirmed LS-SCLC (stage I–III, M0, according to the AJCC 9th edition/IASLC 2016 criteria), received four cycles of platinum-etoposide chemotherapy concurrently with thoracic radiotherapy, and subsequently received at least one dose of durvalumab between January 1, 2020, and December 31, 2023. During the study period, durvalumab consolidation was administered at the discretion of treating physicians based on emerging clinical evidence supporting immunotherapy after chemoradiotherapy in thoracic malignancies and institutional multidisciplinary team discussions. Prior to the public release of the ADRIATIC trial results, the use of durvalumab in LS-SCLC was individualized and off-label. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the institutional review board of Peking University Cancer Hospital (No. 2025YJZ41). Informed consent was obtained from all patients.

Thoracic radiotherapy was required to start no later than the end of the second chemotherapy cycle, with three acceptable dosing regimens: 45 Gy in twice-daily fractions, 54 Gy using a hyperfractionated simultaneous integrated boost (BID–SIB), or 60–66 Gy in once-daily fractions (QD). Patients with mixed SCLC and NSCLC histology, incomplete treatment data, or participation in other interventional clinical studies during durvalumab therapy were excluded from the analysis.

All patients underwent CT-based simulation and were treated with volumetric-modulated arc therapy (VMAT). Involved-field radiotherapy was generally used; the clinical target volume covered the gross primary tumor and clinically involved nodal stations, while elective irradiation of clinically uninvolved nodal regions was not routinely performed (9). Thoracic radiotherapy was delivered continuously without planned split-course interruption; for twice-daily regimens, the two daily fractions were separated by an interval of at least 6 hours. Image-guided radiotherapy was routinely applied for setup verification using cone-beam computed tomography (CT) or orthogonal imaging according to institutional practice.

Positron emission tomography (PET)-CT before radiotherapy planning was performed when clinically available. For patients with available PET-CT, the findings were used to assist the identification of metabolically active primary lesions and clinically involved nodal regions and to support target delineation. Baseline staging examinations included contrast-enhanced chest and abdominal imaging, brain magnetic resonance imaging (MRI), and PET-CT when clinically available. Brain MRI was performed in all patients at initial staging to exclude brain metastasis.

Repeat simulation CT and adaptive replanning were not mandatory for all patients but were performed at the discretion of the radiation oncologist when clinically indicated. The main indications included marked tumor regression, re-expansion of atelectasis, significant weight loss or body contour change, increased setup uncertainty, inadequate target coverage, or potential violation of organ-at-risk dose constraints.

In routine clinical practice, durvalumab was administered intravenously at a fixed dose every 4 weeks. The duration of treatment was determined by disease progression, unacceptable treatment-related toxicity, or physician discretion, with a planned maximum duration of 24 months. Continuation of durvalumab beyond 24 months was permitted at the treating physician’s discretion in selected cases; in this cohort, one patient received durvalumab for 32 months.

Clinical information was retrospectively extracted from electronic medical records, including demographic characteristics, tumor stage, Eastern Cooperative Oncology Group (ECOG) performance status, smoking history, radiotherapy regimen, durvalumab exposure details, and PCI status. Tumor response assessments were conducted in accordance with institutional routine clinical practice, using contrast-enhanced CT or MRI at intervals determined by treating physicians. Data were collected from the date of pathological diagnosis until June 27, 2025, and the date of the first durvalumab administration was defined as the index date. Study quality assurance was ensured by independent cross-verification of data with original source records.

Additional data were retrospectively collected in response to reviewer comments. Radiotherapy dose-volume histogram parameters were extracted from the treatment planning system, including lung V5, lung V20, mean lung dose, maximum spinal cord dose, maximum and mean esophageal doses, mean heart dose, heart V30/V40, and gross tumor volume. Baseline comorbidities were extracted from electronic medical records, including hypertension, diabetes mellitus, cardiovascular disease, chronic pulmonary disease, metabolic disorders, renal dysfunction, thyroid dysfunction, thrombotic history, digestive disease, neurologic or psychiatric disease, and other clinically relevant conditions.

Nutritional and inflammatory parameters, including albumin, C-reactive protein (CRP), body mass index, and pretreatment weight loss, were collected when available. The Glasgow Prognostic Score was calculated in patients with both albumin and CRP data (10). Serum tumor markers and metabolic parameters, including progastrin-releasing peptide (ProGRP), neuron-specific enolase (NSE), and LDL-C, were retrospectively collected when available (11). Pre-durvalumab ProGRP and LDL-C were defined as the most recent values measured before the first dose of durvalumab; when such values were unavailable, the closest diagnostic or follow-up value was recorded for descriptive purposes only. Baseline blood-cell parameters, including neutrophil, lymphocyte, and platelet counts, were collected when available, and neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) were calculated as exploratory immune-inflammatory markers (12). PD-L1 testing status and results were extracted from pathology reports when available; PD-1 expression was not routinely tested in clinical practice.

The primary endpoint was real-world progression-free survival (rwPFS), defined as the time from the first durvalumab administration to investigator-confirmed disease progression or all-cause death, whichever occurred first. Patients who were alive without disease progression were censored at the latest date of recorded tumor assessment. Secondary efficacy endpoints included the duration of durvalumab treatment (DoT), 2-year rwPFS rate, and 2-year OS rate. Safety endpoints included the incidence, type, and severity of treatment-emergent adverse events (TEAEs) and immune-mediated adverse events (imAEs), graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. All AEs occurring from the first dose of durvalumab to 90 days after the last dose (and before the initiation of subsequent anticancer therapy) were included in the safety analysis. Disease recurrence patterns were recorded as the first site of disease relapse, and subsequent anticancer treatments were documented where available.

Statistical analysis

All efficacy analyses were performed in the full analysis set (FAS), which included all enrolled subjects who met the study inclusion and exclusion criteria. Baseline demographic and treatment characteristics were summarized using descriptive statistics. rwPFS and OS were estimated using the Kaplan-Meier method, with medians and 95% CIs calculated using the Brookmeyer and Crowley method. Survival rates at fixed time points were estimated using Greenwood’s formula.

Newly added variables requested by the reviewer were summarized descriptively. Continuous variables were reported as median with interquartile range (IQR) and range, and categorical variables were reported as frequency and percentage. Given the modest sample size and incomplete availability of some biomarkers, exploratory variables were not incorporated into formal multivariable prognostic models.

Statistical analyses were conducted using R software (version 4.3.1) and SAS software (version 9.4). Given the observational study design, effect sizes and 95% CIs were interpreted descriptively rather than inferentially.

Results

Patient characteristics

Between January 2020 and December 2023, a total of 45 patients with LS-SCLC who received cCRT followed by durvalumab consolidation were included in the FAS. The median age was 57 years (range, 38–73 years), and the majority of patients were male (71.1%). Most patients (93.3%) had stage III disease, with 35.6% having stage IIIA and 35.6% having stage IIIB disease. All patients had an ECOG performance status of 0 or 1. Thoracic radiotherapy was delivered as 45 Gy in twice-daily fractions in 15.6% of patients and as 54 Gy hyperfractionated BID-SIB in 84.4% of patients. PCI was administered to 68.9% of the study population. Concurrent chemotherapy consisted mainly of etoposide-cisplatin (EP; 77.8%) and etoposide-carboplatin (EC; 22.2%) (Table 1). Durvalumab consolidation was initiated at a median of 3 weeks (IQR, 3–6 weeks) after the completion of cCRT.

All patients received VMAT. PET-CT was performed in 20 patients (44.4%) for initial staging or radiotherapy planning, whereas 25 patients (55.6%) did not undergo PET-CT and were staged and planned using contrast-enhanced CT, brain MRI, bone scan, and other standard imaging examinations. Brain MRI was performed in all patients at initial staging. Dosimetric parameters are summarized in Table S1. The median lung V5 was 43.6% (IQR, 37.0–49.7%), the median lung V20 was 18.5% (IQR, 15.1–23.2%), and the median mean lung dose was 14.2 Gy (IQR, 10.4–17.0 Gy). The median GTV volume was 54.7 cm³ (IQR, 27.1–84.3 cm³).

Baseline comorbidities are summarized in Table S2. Overall, 33 patients (73.3%) had at least one documented comorbidity, whereas 12 patients (26.7%) had no documented comorbidity. Nutritional and inflammatory variables, ProGRP, GERD, LDL-C, and immune-inflammatory/PD-L1 information are summarized in Tables S3-S7. Because several variables were not uniformly measured at standardized time points, these parameters were reported descriptively.

Efficacy

At the data cutoff date (June 27, 2025), the median follow-up for rwPFS was 53.6 months (95% CI: 43.5–55.3). The median rwPFS was 18.6 months (95% CI: 17.6–39.9), and the 2-year rwPFS rate was 46.7% (95% CI: 31.7–60.3%) (Figure 1A). The 3-year rwPFS rate was 44.1% (95% CI: 29.3–57.9%), and the 4-year rwPFS rate was 40.9% (95% CI: 26.2–55.1%). The median follow-up for OS, calculated using the reverse Kaplan–Meier method, was 51.3 months (95% CI: 42.0–60.6). Median OS was not reached, with an estimated 2-year OS rate of 80.3% (95% CI: 68.9–93.5%) (Figure 1B). The 3- and 4-year OS rates were 80.3% (95% CI: 68.9–93.5%) and 76.3% (95% CI: 63.5–91.6%), respectively. The median DoT of durvalumab was 13.0 months (95% CI: 9.0–not reached), with a 2-year treatment continuation rate of 36.7% (95% CI: 24.2–55.6%) (Figure 1C).

Figure 1 Survival outcomes and duration of durvalumab consolidation. (A) rwPFS. (B) OS. (C) Duration of durvalumab consolidation. CI, confidence interval; DoT, duration of durvalumab treatment; NE, not estimable; NR, not reached; OS, overall survival; rwPFS, real-world progression-free survival.

Recurrence patterns and subsequent therapy

At the data cutoff date (June 27, 2025), 20 of 45 patients (44.4%) had developed disease progression. Isolated intrathoracic progression occurred in 8 patients (17.8%), isolated extrathoracic progression in 8 patients (17.8%), and simultaneous intrathoracic and extrathoracic progression in 4 patients (8.9%) (Table 2). Newly developed extrathoracic lesions were identified in 12 patients (26.7%) at the time of first disease progression. Most patients with extrathoracic progression had involvement of a single extrathoracic organ (17.8%), whereas multiorgan involvement was less common. The brain/central nervous system (CNS) was the most frequent site of newly developed extrathoracic disease (11.1%), followed by bone (8.9%), adrenal gland (6.7%), liver (4.5%), and distant lymph nodes (2.2%) (Table 3). Among the 20 patients who developed disease progression and received second-line therapy, radiotherapy was the most frequently administered treatment modality (7 patients, 35%), followed by supportive care (4 patients, 20%). Chemotherapy alone and chemotherapy combined with immunotherapy were each administered in 3 patients (15% each). Less commonly, chemoradiotherapy, chemotherapy combined with immunotherapy and radiotherapy, and chemotherapy combined with targeted therapy were each used in 1 patient (5% each) (Figure 2).

Figure 2 Distribution of second-line treatment patterns (N=20).

Safety

Overall, durvalumab consolidation therapy was well tolerated, and no treatment-related deaths were reported during the study period. Any TEAE was observed in 37 patients (82.2%). The most common TEAEs were nausea (31.1%), diarrhea (26.7%), and fatigue (17.8%), all of which were grade 1–2 in severity (Table 4). irAEs occurred in 16 patients (35.6%), primarily immune checkpoint inhibitor-induced pneumonitis (CIP; 13.3%) and hypothyroidism (13.3%). Grade 3–4 irAEs were infrequent (6.6%), including two cases of grade 3 CIP and one case of grade 3 hypothyroidism.

Hematologic toxicities were frequent in the study population: leukopenia (75.6%), neutropenia (57.8%), thrombocytopenia (48.9%), and anemia (44.4%). Grade 3–4 leukopenia and neutropenia occurred in 28.9% and 35.6% of patients, respectively; febrile neutropenia was observed in 8.9% of patients (Table 4). Durvalumab was permanently discontinued in 17.8% of patients due to treatment-related adverse events (TRAEs). No new or unexpected safety signals were identified in this real-world cohort.

Discussion

This single-center real-world analysis demonstrates that durvalumab consolidation after cCRT yields durable disease control with an acceptable toxicity profile in patients with LS-SCLC. The median rwPFS and 2-year OS rate observed in this real-world cohort are consistent with the results of the phase III ADRIATIC trial (8), supporting the external generalizability of the survival benefit of durvalumab beyond the confines of randomized clinical studies. These results also extend earlier evidence from patients with unresectable stage III NSCLC, where durvalumab consolidation after cCRT improved survival outcomes and established a new treatment paradigm (7).

The recently reported Japanese subgroup analysis of the ADRIATIC trial is important for interpreting durvalumab consolidation in Asian patients (13). The lack of a clearly positive result in the Japanese subgroup should be interpreted cautiously because subgroup analyses are exploratory and may have limited statistical power. A brief descriptive comparison also suggests differences in radiotherapy and PCI practice. In the Japanese subgroup, the proportions of once-daily and twice-daily thoracic radiotherapy were 10.5%/89.5% and 0%/100% in the two treatment groups, and the proportions of patients receiving PCI were 52.6% and 58.1%, respectively. In contrast, all patients in our cohort received twice-daily thoracic radiotherapy, and PCI was delivered to 68.9% of patients. These differences, together with differences in patient characteristics, subsequent treatment, and follow-up patterns, may contribute to regional heterogeneity. Therefore, the Japanese subgroup findings do not necessarily indicate a lack of benefit in Asian patients, but highlight the need for additional real-world data and prospective Asian studies.

Mechanistically, PD-L1 blockade restores antitumor T-cell function and reinstates immune surveillance against tumor cells (4), while radiotherapy augments tumor antigen release, upregulates major histocompatibility complex class I (MHC-I) expression, and enhances dendritic cell priming—providing a strong biological foundation for the radio-immunotherapeutic synergy observed in LS-SCLC (6,14). Our study cohort was predominantly treated with contemporary twice-daily hyperfractionated thoracic radiotherapy, suggesting that this optimized fractionation schedule can be delivered safely in combination with PD-L1 inhibition and may contribute to durable disease control. These findings complement randomized data demonstrating the efficacy of twice-daily radiotherapy schedules in patients with LS-SCLC (2). Historically, the pivotal trial by Turrisi et al. established the superiority of twice-daily radiotherapy over once-daily radiotherapy in LS-SCLC (15), providing the radiotherapeutic foundation for the integration of high-fractionation regimens with immunotherapy in this disease.

Target-volume design may be particularly relevant in the era of radio-immunotherapy. We generally used involved-field radiotherapy rather than elective nodal irradiation, which may help limit unnecessary exposure of circulating immune cells and uninvolved nodal regions (9). Prior studies evaluating elective nodal irradiation, involved-field radiotherapy, and effective dose to immune cells (EDIC) suggest that thoracic irradiation can influence lymphocyte nadir and clinical outcomes in SCLC (16,17). These data support careful balancing of target coverage and immune preservation when integrating thoracic radiotherapy with PD-L1 blockade.

Disease failure patterns in the immunotherapy era remain clinically relevant for guiding subsequent treatment strategies. Post-durvalumab management in our cohort was heterogeneous: most patients with recurrent disease received active anticancer therapy, with radiotherapy frequently used for oligometastatic or localized relapse. A considerable proportion of patients received systemic therapy (chemotherapy with or without immunotherapy), whereas a smaller subset was managed with supportive care alone. This variability in second-line treatment reflects the absence of standardized post-immunotherapy treatment protocols for relapsed LS-SCLC and highlights the need for prospective clinical trials to evaluate optimal treatment sequencing strategies in this setting.

Recent studies have shown that intracranial disease failure remains a substantial clinical challenge even in the immunotherapy era; stereotactic radiosurgery (SRS) or MRI-based surveillance has not eliminated distant brain relapse (18), suggesting that individualized integration of PCI and imaging follow-up remains essential for patients with LS-SCLC. Moreover, modern clinical reviews emphasize that the role of PCI is evolving in the era of immune checkpoint inhibitors (ICIs) and should be guided by risk stratification and neuroimaging-based decision-making pathways (19).

The safety profile of durvalumab consolidation observed in this real-world cohort was consistent with prior reports from clinical trials. The rate of grade ≥3 irAEs (6.6%) was low and comparable to that reported in the ADRIATIC trial (9), aligning with clinical experience in thoracic oncology that careful treatment planning and vigilant clinical monitoring can mitigate overlapping pulmonary toxicities when combining chest irradiation and ICIs (20). No new or unexpected toxicities were identified in our study. In contrast, hematologic toxicities were more frequently observed in our real-world cohort than in the ADRIATIC trial population. This discrepancy likely reflects differences in treatment context: in routine clinical practice, durvalumab consolidation is initiated shortly after the completion of cCRT, and hematologic adverse events may partly represent residual or delayed toxic effects of prior chemoradiotherapy rather than immune-mediated toxicity alone.

Mechanistically, prior thoracic radiotherapy may enhance immune activation in the tumor microenvironment but also confound the clinical recognition of ICI-related pneumonitis, as radiation pneumonitis and CIP share similar clinical and radiological features. Multiple clinical analyses underscore the importance of distinguishing radiation-induced pneumonitis from ICI-induced pneumonitis, establishing clear toxicity grading and management algorithms, and exercising caution when considering ICI rechallenge in patients with a history of severe pneumonitis (21-23).

Translational research advances have highlighted the molecular heterogeneity of SCLC, including distinct transcriptional subtypes (SCLC-A/N/P/I) with divergent immune microenvironments that likely modulate checkpoint inhibitor responsiveness (24-26). Additionally, retrospective studies suggest that prior radiotherapy exposure is associated with improved clinical outcomes to subsequent PD-1/PD-L1 blockade (26), implying a potential “radiation priming effect” on the antitumor immune response that warrants prospective validation in SCLC. Furthermore, longitudinal imaging and biomarker studies indicate that chronic ICI-related pneumonitis can persist or recur over time (22), reinforcing the need for standardized long-term monitoring and intervention frameworks in real-world clinical practice.

In parallel, novel systemic treatment options for relapsed SCLC—such as antibody-drug conjugates (e.g., DLL3-targeting agents) and DLL3-directed T-cell engagers—as well as rational combination strategies are being actively explored to enhance systemic disease control after relapse (27,28). These agents build on the broader success of chemo-immunotherapy in extensive-stage SCLC and the clinical activity of emerging agents in later lines of therapy. Of particular relevance, the DLL3-targeting bispecific T-cell engager tarlatamab has demonstrated a significant OS advantage over chemotherapy in the phase III DeLLphi-304 trial (29), with real-world data highlighting cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) as manageable early-cycle toxicities (30). These novel agents may complement consolidation immunotherapy and local salvage strategies to improve post-relapse systemic disease control in patients with LS-SCLC.

The strengths of this study include the uniform application of contemporary cCRT regimens, detailed capture of treatment and clinical outcome data, and long-term follow-up of the study cohort—all of which enhance the clinical relevance of the findings. However, this study also has several limitations that should be considered when interpreting the results. First, the retrospective single-institution study design is inherently subject to selection bias. Second, the modest sample size limits the ability to perform meaningful subgroup analyses and draw definitive conclusions about treatment outcomes in specific patient populations (e.g., patients with different radiotherapy regimens or ECOG performance status). Third, the lack of centralized independent imaging review may have introduced variability in the assessment of disease progression and tumor response. Despite these limitations, the concordance of our real-world results with the global trial outcomes of the ADRIATIC trial supports the robustness of our findings and their generalizability to routine clinical practice.

Additional limitations are related to the retrospective collection of comorbidities and biomarkers. Standardized comorbidity scales, such as the Charlson Comorbidity Index and MRC dyspnea scale, were not uniformly available (31). CRP, ProGRP, LDL-C, NLR/PLR, and PD-L1 were not tested at standardized time points in all patients; therefore, their prognostic value could not be formally evaluated in multivariable models (32-34). GERD was documented in only one patient, precluding survival analysis for this factor (35). These variables should be prospectively collected in future studies.

Conclusions

In summary, durvalumab consolidation after cCRT confers clinically meaningful and durable survival benefits with a manageable toxicity profile in real-world clinical practice for patients with LS-SCLC. These data reinforce the role of durvalumab as the standard of care for post-cCRT consolidation in patients with LS-SCLC and motivate further prospective clinical research to optimize the integration of radio-immunotherapy, establish evidence-based treatment strategies for relapsed disease, and deploy biomarker-guided patient selection to further improve clinical outcomes in this aggressive malignancy.

Acknowledgments

This study was previously presented as a Conference Abstract on the ESMO Immuno-Oncology and Technology webpage in 2025. The authors thank the patients and their families, as well as all clinical and research staff involved in patient care, data collection, and study coordination.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://tlcr.amegroups.com/article/view/10.21037/tlcr-2026-0287/rc

Data Sharing Statement: Available at https://tlcr.amegroups.com/article/view/10.21037/tlcr-2026-0287/dss

Peer Review File: Available at https://tlcr.amegroups.com/article/view/10.21037/tlcr-2026-0287/prf

Funding: This work was supported by AstraZeneca China, the Beijing Research Ward Excellence Program (Nos. BRWEP2024W032150100 and BRWEP2024W032150110), the Wu Jieping Medical Foundation (grant number 320.6750.2022-03-48), Beijing Nova Program (No. 20250484920), Clinical Research Fund for Distinguished Young Scholars of Peking University Cancer Hospital (grant number QNJJ202410), Science Foundation of Peking University Cancer Hospital (grant number BJCH2025GG05), and Peking University Clinical Scientist Training Program, supported by the Fundamental Research Funds for the Central Universities (grant number BMU2025PYJH041).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tlcr.amegroups.com/article/view/10.21037/tlcr-2026-0287/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the institutional review board of Peking University Cancer Hospital (No. 2025YJZ41). Informed consent was obtained from all patients.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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