Background Large language models (LLMs) such as ChatGPT (OpenAI) are increasingly discussed as potential tools for patient education in health care. In radiation oncology, where patients are often confronted with complex medical terminology and complex treatment plans, LLMs may support patient understanding and promote more active participation in care. However, the readability, accuracy, completeness, and overall acceptance of LLM-generated medical content remain underexplored. Objective This study aims to evaluate the potential of ChatGPT-4 as a supplementary tool for patient education in the context of lung cancer radiotherapy by assessing the readability, content quality, and perceived usefulness of artificial intelligence–generated responses from both clinician and patient perspectives. Methods A total of 8 frequently asked questions about radiotherapy for lung cancer were developed based on clinical experience from a team of clinicians specialized in lung cancer treatment at a university hospital. The questions were submitted individually to ChatGPT-4o (version as of July 2024) using the prompt: “I am a lung cancer patient looking for answers to the following questions.” Responses were evaluated using three approaches: (1) a readability analysis applying the Modified Flesch Reading Ease (FRE) formula for German and the 4th Vienna Formula (WSTF); (2) a multicenter expert evaluation by 6 multidisciplinary clinicians (radiation oncologists, medical oncologists, and thoracic surgeons) specialized in lung cancer treatment using a 5-point Likert scale to assess relevance, correctness, and completeness; and (3) a patient evaluation during the first follow-up appointment after radiotherapy, assessing comprehensibility, accuracy, relevance, trustworthiness, and willingness to use ChatGPT for future medical questions. Results Readability analysis classified most responses as “very difficult to read” (university level) or “difficult to read” (upper secondary school), likely due to the use of medical language and long sentence structures. Clinician assessments yielded high scores for relevance (mean 4.5, SD 0.52) and correctness (mean 4.3, SD 0.65), but completeness received slightly lower ratings (mean 3.9, SD 0.59). A total of 30 patients rated the responses positively for clarity (mean 4.4, SD 0.61) and relevance (mean 4.3, SD 0.64), but lower for trustworthiness (mean 3.8, SD 0.68) and usability (mean 3.7, SD 0.73). No harmful misinformation was identified in the responses. Conclusions ChatGPT-4 shows promise as a supplementary tool for patient education in radiation oncology. While patients and clinicians appreciated the clarity and relevance of the information, limitations in completeness, trust, and readability highlight the need for clinician oversight and further optimization of LLM-generated content. Future developments should focus on improving accessibility, integrating real-time readability adaptation, and establishing standardized evaluation frameworks to ensure safe and effective clinical use.

Due to demographic shifts, the population is aging, and patients are experiencing more comorbidities. Stereotactic body radiotherapy (SBRT) offers high rates of local control for patients with medically inoperable early-stage non-small cell lung cancer (NSCLC). However, obtaining histopathological confirmation can be challenging due to severe comorbidities, small tumors, or unfavorable anatomical locations. Between 2011 and 2022, we retrospectively analyzed a cohort of patients who underwent lung SBRT for presumed early-stage NSCLC at our institution. Out of 486 consecutive patients treated during this period, 56 patients (11.5

Background:Stereotactic body radiation therapy (SBRT) is the established standard of care for medically inoperable early-stage non-small cell lung cancer (ES-NSCLC). When a biopsy is unfeasible, it is often delivered empirically, yet long-term outcomes and failure patterns remain underreported. Methods:A total of 56 patients with clinically staged T1-T3N0M0 lung tumors treated with empiric SBRT (2011-2022) were retrospectively analyzed. Nineteen patients with recurrence were assessed for failure patterns and survival. Overall survival (OS), progression-free survival (PFS), local failure-free survival (LFFS), regional failure-free survival (RFFS), and distant metastasis-free survival (DMFS) were estimated using the Kaplan-Meier method. Competing risk analysis was performed with death treated as a competing event. Results:At a median follow-up of 80.4 months (95% CI: 65.2-95.6), 17 patients (30.4%) were alive. Median PFS and OS were 28.5 months (95% CI: 16.4-40.8) and 41.7 months (95% CI: 14.0-69.4), respectively. LFFS was 84.1% at 5 years and 67.3% at 10 years, RFFS was 64.7% at 5 years and 58.8% at 10 years, and DMFS was 62.4% at 5 years and 56.1% at 10 years. Pathologic confirmation of recurrence was obtained in 10 patients, identifying NSCLC in six, small cell lung cancer in three, and urothelial carcinoma in one. Local failures were infrequent and occurred early (median 8.3 months), whereas regional and distant recurrences occurred later (median 13.5 and 22.8 months). At 10 years, the estimated cumulative incidence function was 6.3% for local failure, 14.8% for regional failure, 16.6% for distant failure, and 55.8% for death. Conclusion:Empiric SBRT provides durable local control in presumed early-stage NSCLC, but outcomes are limited by comorbid mortality and systemic progression. These findings emphasize its effectiveness as a local therapy and the need for prolonged surveillance and systemic strategies.

BACKGROUND:Due to demographic shifts, the population is aging, and patients are experiencing more comorbidities. Stereotactic body radiotherapy (SBRT) offers high rates of local control for patients with medically inoperable early-stage non-small cell lung cancer (NSCLC). However, obtaining histopathological confirmation can be challenging due to severe comorbidities, small tumors, or unfavorable anatomical locations. METHODS:Between 2011 and 2022, we retrospectively analyzed a cohort of patients who underwent lung SBRT for presumed early-stage NSCLC at our institution. Out of 486 consecutive patients treated during this period, 56 patients (11.5%) with a total of 61 lesions were identified and included in this retrospective study. All included patients lacked histopathological confirmation prior to treatment and had no evidence of other active malignancies. The primary objective of this analysis was to evaluate pulmonary function tests before and after SBRT, including long-term follow-up. RESULTS:The median overall survival (OS) after empiric SBRT was 50.7 months (95% confidence interval [CI] 12.8-88.7). Survival rates at 1 year and 2 years were 88.4 and 71.1%, respectively. The 1‑, 2‑ and 3‑year local control rates were 96.6%, 92.3% and 87.1%. Pulmonary function tests indicated a relative increase in the mean forced expiratory volume in 1 s (FEV1) of 0.55% (SD 13.5) and 2.0% (SD: 20.0) at 6 and 12 months, respectively. In contrast, the mean diffusing capacity of the lungs for carbon monoxide (DLCO) showed a relative decline of 7.4% (SD 16.6) and 6.3% (SD 26.1) at 6 and 12 months, respectively. Patients with lower comorbidity scores (CCI ≤ 5) exhibited significantly improved OS (p = 0.011). Long-term oxygen therapy (LTOT) prior to SBRT was associated with shorter OS (p = 0.02) and a relatively high incidence of grade 2-3 pulmonary disorders. Chronic obstructive pulmonary disease (COPD) was identified as a possible risk factor for severe treatment-related toxicity. Notably, all patients who experienced grade 3 pulmonary disorders required LTOT before SBRT. CONCLUSION:Empiric SBRT is a safe and effective treatment for presumed early-stage NSCLC in patients without histopathological confirmation. Even in patients requiring oxygen therapy and with severe comorbidities, long-term survival is feasible with acceptable treatment-related toxicity. Optimal dose fractionation and biologically effective dose (BED) levels for frail patients without histological confirmation remain undefined. Prospective trials are warranted to determine the most effective and safe SBRT regimens for this vulnerable patient population.

Background:Large language models (LLMs) such as ChatGPT (OpenAI) are increasingly discussed as potential tools for patient education in health care. In radiation oncology, where patients are often confronted with complex medical terminology and complex treatment plans, LLMs may support patient understanding and promote more active participation in care. However, the readability, accuracy, completeness, and overall acceptance of LLM-generated medical content remain underexplored. Objective:This study aims to evaluate the potential of ChatGPT-4 as a supplementary tool for patient education in the context of lung cancer radiotherapy by assessing the readability, content quality, and perceived usefulness of artificial intelligence-generated responses from both clinician and patient perspectives. Methods:A total of 8 frequently asked questions about radiotherapy for lung cancer were developed based on clinical experience from a team of clinicians specialized in lung cancer treatment at a university hospital. The questions were submitted individually to ChatGPT-4o (version as of July 2024) using the prompt: "I am a lung cancer patient looking for answers to the following questions." Responses were evaluated using three approaches: (1) a readability analysis applying the Modified Flesch Reading Ease (FRE) formula for German and the 4th Vienna Formula (WSTF); (2) a multicenter expert evaluation by 6 multidisciplinary clinicians (radiation oncologists, medical oncologists, and thoracic surgeons) specialized in lung cancer treatment using a 5-point Likert scale to assess relevance, correctness, and completeness; and (3) a patient evaluation during the first follow-up appointment after radiotherapy, assessing comprehensibility, accuracy, relevance, trustworthiness, and willingness to use ChatGPT for future medical questions. Results:Readability analysis classified most responses as "very difficult to read" (university level) or "difficult to read" (upper secondary school), likely due to the use of medical language and long sentence structures. Clinician assessments yielded high scores for relevance (mean 4.5, SD 0.52) and correctness (mean 4.3, SD 0.65), but completeness received slightly lower ratings (mean 3.9, SD 0.59). A total of 30 patients rated the responses positively for clarity (mean 4.4, SD 0.61) and relevance (mean 4.3, SD 0.64), but lower for trustworthiness (mean 3.8, SD 0.68) and usability (mean 3.7, SD 0.73). No harmful misinformation was identified in the responses. Conclusions:ChatGPT-4 shows promise as a supplementary tool for patient education in radiation oncology. While patients and clinicians appreciated the clarity and relevance of the information, limitations in completeness, trust, and readability highlight the need for clinician oversight and further optimization of LLM-generated content. Future developments should focus on improving accessibility, integrating real-time readability adaptation, and establishing standardized evaluation frameworks to ensure safe and effective clinical use.

Artificial intelligence models like ChatGPT have advanced significantly, with GPT-4o offering improved accuracy and contextual understanding. In healthcare, ChatGPT provides accessible explanations of complex medical concepts, aiding patient education and reducing clinician workload. It is particularly effective in simplifying medical jargon, addressing patient questions, and fostering engagement. However, limitations include misinformation risks, outdated data, and potential biases. For lung cancer, the leading cause of cancer-related deaths globally, patients require reliable, comprehensive, and accessible educational tools, particularly for complex treatments like radiotherapy. ChatGPT offers potential as a supplementary resource to meet these needs, though careful oversight is required to address its shortcomings. This study aims to evaluate the educational capabilities and limitations of GPT-4 for patients undergoing radiotherapy for lung cancer, focusing on clinician-led assessments of relevance, accuracy, and completeness, patient-led evaluations of educational content, and a readability analysis to assess response accessibility. Eight questions related to lung cancer radiotherapy were posed to GPT-4 (July 2024) via OpenAI’s web interface. Responses were assessed for readability using the Modified Flesch Reading Ease (FRE) Formula and the 4th Vienna Formula (WSTF). Six clinicians (two radiation oncologists, two medical oncologists, and two thoracic surgeons) experienced in the treatment of lung cancer rated relevance, correctness, and completeness on a five-point Likert scale (1 = strongly disagree, 5 = strongly agree). Patients evaluated comprehensibility, accuracy, relevance, trustworthiness, and willingness to use ChatGPT for future medical questions during post-radiotherapy follow-up. Data were analyzed using descriptive statistics (median, mean, standard deviation) in Microsoft Excel (version 2410). Figures were created in Python (version 3.8) using Matplotlib, with data structured in Pandas DataFrames for analysis and visualization. ChatGPT's responses were classified as "very difficult" or "difficult to read" in the readability analysis using the Modified Flesch Reading Ease (FRE) and the 4th Vienna Formula (WSTF) (FRE: 23.36 ± 11.16, WSTF: 13.81 ± 2.01). Clinicians rated relevance (3.7–4.3), correctness (3.5–4.3), and completeness (3.5–4.2), with ChatGPT's response to the question "What follow-up care is required after radiotherapy for lung cancer?'' scoring highest across all dimensions. Thirty consecutive patients (48 – 87 years, median: 66 years) who received radiotherapy for lung cancer rated clarity highly ("easy to understand": 4.4 ± 0.61), but trustworthiness and usability scored lower ("confidence in information": 4.0 ± 0.84). These results highlight ChatGPT's strengths in accessibility and relevance, with room for improvement in trustworthiness and usability. ChatGPT shows promise as a supplementary tool for patient education in radiation oncology, offering clear and relevant information. However, limitations in completeness and trustworthiness necessitate careful review and supplementation by healthcare professionals. Further advancements and standardized evaluation criteria are essential for its effective integration into clinical practice.

e20603 Background: Assessment of salvage treatment for newly developed metastases in patients previously treated with curative-intent concurrent chemoradiation (cCRT) +/- immune checkpoint inhibition (ICI) for unresectable stage III NSCLC. Methods: We analysed data of 136 patients treated from 2011 to 2020 in as single tertiary cancer centre. Location of first observed distant metastasis (DM) were categorized as brain/intracranial metastasis (BM), organ metastasis (OM) and skeletal metastasis (SM). Treatment with radiotherapy (RT) and systemic therapy (ST); sub-divided into chemo- (CT), immuno (IT) and tyrosine kinase inhibitor therapy (TKI) was assessed. Results: All patients received definitive cCRT ≥ 60 Gy with 2 courses of chemotherapy. Thirty-six (26%) patients received ICI. Median follow-up was 49.7 months, median PFS was 9.9 (95%CI: 7.0-12.7) months, 12- and 24-month PFS-rates were 42% and 29%, respectively. Median OS was 31.2 months (95% CI 16.9 – 45.6), 12- und 24-month-OS-rates were 74% und 53%. Sixty-one patients (45%) developed metastasis: 21 (15%) BM, 20 (15%) OM und 20 (15%) SM. Median OS of patients with BM, OM and SM was 27.4, 25.5 and 17.9 months, respectively (p = 0.821). In total 45/61 patients were initially treated with cCRT and 16 with cCRT+ICI. Median OS was 26.5 (cCRT+ICI) vs. 23.4 (cCRT) months (p = 0.121); 12- and 24- month survival rates were 94% vs. 64% and 63% vs. 47%. Patients with SM survived significantly longer, if the initial treatment included ICI (Median not reached vs. 7.5 months; p = 0.042). Fifty-three (87%) of 61 patients received the following salvage therapy: 28 (53%) RT, 10 (19%) ST and 15 (28%) combined RT + ST. Patients with SM showed a trend towards longer OS after RT-alone (p = 0.069). Thirteen patients with adenocarcinoma received ST: 7 CT and 6 TKI with a significant longer OS (40.1 months TKI vs. 12.1 months CT; p = 0.040). All 21 patients with BM were treated with RT. Patients treated with stereotactic radiosurgery (SRS) showed a significant longer OS of 40.1 months vs. 12.2 months for patients treated with whole brain radiotherapy (WBRT) (p = 0.016). Conclusions: Patients with SM had a significantly longer OS if their initial therapy consisted of cCRT+ICI vs. cCRT alone. Patients with BM as first site of metastasis had a significantly longer OS when treated with SRS vs. WBRT. Salvage treatment with TKI resulted in a significantly longer OS compared to salvage CT in patients with adenocarcinomas.

Purpose The aim of this study was to investigate a first-site-metastasis pattern (FSMP) in unresectable stage III NSCLC after concurrent chemoradiotherapy (cCRT) with or without immune checkpoint inhibition (ICI). Methods We defined three patient subgroups according to the year of initial multimodal treatment: A (2011–2014), B (2015–2017) and C (2018–2020). Different treatment-related parameters were analyzed. Observed outcome parameters were brain metastasis-free survival (BMFS), extracranial distant metastasis-free survival (ecDMFS) and distant metastasis-free survival (DMFS). Results 136 patients treated between 2011 and 2020 were included with ≥ 60.0 Gy total dose and concurrent chemotherapy (cCRT); thirty-six (26%) received ICI. Median follow-up was 49.7 (range:0.7–126.1), median OS 31.2 (95% CI:16.4–30.3) months (23.4 for non-ICI vs not reached for ICI patients, p = 0.001). Median BMFS/ecDMFS/DMFS in subgroups A, B and C was 14.9/16.3/14.7 months, 20.6/12.9/12.7 months and not reached (NR)/NR/36.4 months ( p = 0.004/0.001/0.016). For cCRT+ICI median BMFS was 53.1 vs. 19.1 months for cCRT alone ( p = 0.005). Median ecDMFS achieved 55.2 vs. 17.9 ( p = 0.003) and median DMFS 29.5 (95% CI: 1.4–57.6) vs 14.93 (95% CI:10.8–19.0) months ( p = 0.031), respectively. Multivariate analysis showed that age over 65 (HR:1.629; p = 0.036), GTV ≥ 78 cc (HR: 2.100; p = 0.002) and V20 ≥ 30 (HR: 2.400; p = 0.002) were negative prognosticators for BMFS and GTV ≥ 78 cc for ecDMFS (HR: 1.739; p = 0.027). After onset of brain metastasis (BM), patients survived 13.3 (95% CI: 6.4–20.2) months and 8.6 months (95% CI: 1.6–15.5) after extracranial-distant-metastasis (ecDM). Patients with ecDM as FSMP reached significantly worse overall survival of 22.1 (range:14.4–29.8) vs. 40.1 (range:18.7–61.3) months ( p = 0.034) in the rest of cohort. In contrast, BM as FSMP had no impact on OS. Conclusion This retrospective analysis of inoperable stage III NSCLC patients revealed that age over 65, V20 ≥ 30 and GTV ≥ 78 cc were prognosticators for BMFS and GTV ≥ 78 cc for ecDMFS. ICI treatment led to a significant improvement of BMFS, ecDMFS and DMFS. ecDM as FSMP was associated with significant deterioration of OS, whereas BM as FSMP was not.

Purpose/aim The international standard for patients with large inoperable stage III NSCLC is durvalumab consolidation after concurrent chemoradiotherapy (CRT). In this single centre observational study based on individual data, we prospectively evaluated the role of concurrent/sequential versus sequential immune checkpoint inhibition (ICI). Methods and patients In total, 39 stage III NSCLC patients were prospectively enrolled, 11 (28%) patients were treated with simultaneous and consolidation therapy with PD-1 inhibition (nivolumab) (SIM-cohort) and 28 (72%) patients received PD-L1 inhibition (durvalumab) as consolidation treatment up to 12 months after the end of CRT (SEQ-cohort). Results For the entire cohort, median progression-free survival (PFS) was 26.3 months and median survival (OS), locoregional recurrence-free survival and distant metastasis-free survival were not reached. For the SIM-cohort, median OS was not reached and PFS was 22.8 months, respectively. In the SEQ-cohort, neither median PFS nor OS were reached. After propensity score matching, PFS at 12/24 months were 82/44% in the SIM-cohort and 57/57% in the SEQ-cohort ( p = 0.714), respectively. In the SIM-cohort, 36.4/18.2% of patients showed grade II/III pneumonitis; in the SEQ-cohort 18.2/13.6% after PSM ( p = 0.258, p = 0.55). Conclusion Both concurrent/sequential and sequential ICI show a favorable side effect profile and promising survival in treated patients with inoperable large stage III NSCLC. Concurrent ICI showed a numerical non-significant improvement regarding 6- and 12-months PFS and distant control compared to sequential approach in this small study. However, concurrent ICI to CRT was associated with a non-significant moderate increase in grade II/III pneumonitis.

e20578 Background: To investigate the impact of treatment patterns in inoperable stage III NSCLC following concurrent chemoradiotherapy with or without immune checkpoint inhibition (cCRT±ICI). Methods: Patients were stratified by treatment year and divided into three subgroups: A (2011–2014), B (2015–2017) and C (2018–2020). Patient- and treatment-related characteristics regarding to PFS and OS were analyzed. Survival parameters were calculated from the last day of thoracic radiotherapy (TRT). Results: 136 consecutive enrolled patients were included. Median follow-up (FU) was 35.7 months; median age was 66.9 years. All patients completed TRT to a total dose ≥60.0 Gy; Median radiotherapy planning target volume (PTV) was 700 cc (range: 172.5–2293.2). Thirty-six (26%) patients received ICI. Median PFS in subgroups A, B and C was 8.0, 8.2 and 26.3 months (p = 0.007). Median OS was 19.9 months, 23.4 months and not reached in subgroups A, B and C (p < 0.05). In subgroup C, median PFS was 14.2 vs. 26.3 months in patients treated with and without ICI. On multivariate analysis for the entire cohort, PTV > 700cc was a negative prognosticator of PFS (HR: 1.522; p = 0.042) and OS (HR: 2.671; p = 0.001); ICI was a predictor of improved PFS (HR: 0.571; p = 0.071) and longer OS (HR: 0.401; p = 0.062). In the Non-ICI cohort, multivariate analyses revealed PTV > 700cc (HR: 1.630; p = 0.047) and SUVmax > 13.75 (HR: 1.859; p = 0.012) were predictors of reduced PFS; PTV > 700cc (HR: 1.958; p = 0.017), SUVmax > 13.75 (HR: 2.405; p = 0.002) and total lung V20 > 30 (HR: 3.357; p < 0.05) were predictors of longer OS. Conclusions: Regardless of ICI, patients receiving multimodal therapy after 2018 demonstrated improved survival compared to patients treated earlier. Both PTV > 700cc and ICI were predictive for PFS and OS in the entire cohort.

NUT carcinoma (NC) is a rare and extremely aggressive form of cancer, usually presenting with intrathoracic or neck manifestations in adolescents and young adults. With no established standard therapy regimen and a median overall survival of only 6.5 months, there is a huge need for innovative treatment options. As NC is genetically driven by a single aberrant fusion oncoprotein, it is generally characterized by a low tumor mutational burden, thus making it immunologically cold and insusceptible to conventional immunotherapy. Recently, we have demonstrated that oncolytic viruses (OVs) are able to specifically infect and lyse NC cells, thereby turning an immunologically cold tumor microenvironment into a hot one. Here, we report an intensive multimodal treatment approach employing for the first time an OV (talimogene laherparepvec (T-VEC); IMLYGIC®) together with the immune checkpoint inhibitor pembrolizumab as an add-on to a basic NC therapy (cytostatic chemotherapy, radiation therapy, epigenetic therapy) in a patient suffering from a large thoracic NC tumor which exhibits an aberrant, unique BRD3:NUTM1 fusion. This case demonstrates for the first time the feasibility of this innovative add-on immunovirotherapy regimen with a profound, repetitive and durable replication of T-VEC that is instrumental in achieving tumor stabilization and improvement in the patient´s quality of life. Further, a previously unknown BRD3:NUTM1 fusion gene was discovered that lacks the extraterminal domain of BRD3.

To investigate the impact of treatment time and patterns in inoperable stage III non-small cell lung cancer (NSCLC) following concurrent chemoradiotherapy (cCRT) ± immune checkpoint inhibitors (ICIs). Patients were stratified by treatment year: A (2011–2014), B (2015–2017) and C (2018–2020). Tumor- and treatment-related characteristics regarding locoregional recurrence-free survival (LRRFS), progression-free survival (PFS) and overall survival (OS) were investigated. One hundred and thirty-six consecutive patients were analyzed. All patients completed thoracic radiotherapy (TRT) to a total dose ≥ 60.0 Gy; 36 (26

e20557 Background: The present study evaluates outcome after chemoradiotherapy (CRT) with concurrent and/or sequential Programmed Cell Death 1 (PD-1) or Ligand 1 (PD-L1) immune checkpoint inhibition (CPI) for inoperable stage III NSCLC patients depending on planning target volume (PTV). Methods: Prospective data of thirty-nine consecutive patients with inoperable stage III NSCLC who completed CRT with sequential durvalumab (72%, 28 patients) or concurrent and sequential nivolumab (28%, 11 patients) were analyzed. Different cut offs for PTV as well as PTV as a continuous variable were evaluated for association with progression-free survival (PFS) and extracranial metastasis-free survival (eMFS). Results: All patients were treated with conventionally fractionated TRT to a total dose of at least 60 Gy (range: 60-63.6Gy), 97% (27 patients) received two cycles of concurrent platinum-based chemotherapy. Median follow-up for the entire cohort was 23.2 (range: 6.0-42.6) months; median overall survival (OS) and eMFS were not reached. Median Progression-free survival (PFS) was 22.8 (95% CI: 10.3-35.2) months. Age (65 years), gender and UICC stage had no significant impact on PFS. There was no significant difference between durvalumab and nivolumab patients. Patients with PTV ≥ 900ccm had a significantly shorter PFS (11.77 vs 26.3 months, p = 0.049) and eMFS (11.7 months vs not reached, p = 0.019). Furthermore, patients with PTV ≥ 900ccm and stage IIIC disease (TNM 8th Ed.) achieved a dismal median PFS of only 3.6 months (vs. 26.3 months p < 0.001). PTV as a continuous variable showed a trend for association with PFS (p = 0.064) and was a significant negative prognosticator for eMFS (p = 0.030; HR: 4.065; 95%CI: 1.148-14.397). Conclusions: PTV has a significant impact on the PFS and eMFS after CRT combined with concurrent and/or sequential CPI in inoperable stage III NSCLC. Patients with PTV ≥ 900ccm had a significantly shorter PFS and eMFS.