Thymic epithelial tumors (TETs) are rare thymic neoplasms. There are approximately 1.5 cases per million TETs per year. They are the most common anterior mediastinal tumors in adults. Due to limited activity of available treatment options novel strategies and treatment options are needed and treatment with immune checkpoint inhibitors is an attractive option. Thymic epithelial tumors have one of the lowest tumor mutational burden among all cancer in adults, but high expression of PD-L1 on tumor cells and abundant CD8+ lymphocytes provide a strong rational for implementing immune checkpoint inhibitors (ICIs) which target PD-1/PD-L1 pathway in the treatment of TETs. Few small early stage clinical trials were published so far evaluating efficacy of pembrolizumab and avelumab in thymoma and thymic carcinoma patients. Al trials showed reasonable response rates and progression-free survival. Higher PD-L1 expression was predictor of response in all trials. However, increased incidence of immune-related adverse events was seen in TET patients treated with immune checkpoint inhibitors compared to patients with other cancers. At the moment, ICIs are not standard of care for patients with TET and larger trials are needed to establish the right role of ICIs regarding efficacy and safety of these agents.

Small cell lung cancer (SCLC) is an aggressive malignancy characterized by rapid proliferation, early dissemination, acquired therapy resistance, and poor prognosis. Early diagnosis of SCLC is crucial since most patients present with advanced/metastatic disease, limiting the potential for curative treatment. While SCLC exhibits initial responsiveness to chemotherapy and radiotherapy, treatment resistance commonly emerges, leading to a five-year overall survival rate of up to 10%. New effective biomarkers, early detection, and advancements in therapeutic strategies are crucial for improving survival rates and reducing the impact of this devastating disease. This review aims to comprehensively summarize current knowledge on diagnostic options, well-known and emerging biomarkers, and SCLC treatment strategies and discuss future perspectives on this aggressive malignancy.

Results: The median age of presentation was 57 years, and 47% (n ¼ 57) patients were aged 40-60 years. There were with 55 % males (n ¼ 67), 86 % (n ¼ 104) of all patients were non smokers. PDL1 was positive in 38.8 % (n ¼ 47) patients, with 12.4 % (n ¼ 15) patients having PDL1 ! 50%. PDL1 positivity was not significantly different among gender, smoking status or age or various EGFR mutations. Of all the patients, 15 patients did not take therapy. So survival analysis was possible only for 106 patients. Progression free survival (PFS) for PDL1 negative patients was 11 months (95% C.I. 8.6-13.6 months), while for PDL1 positive patients was 13 months (95% C.I. 6.3-19.6 months) p ¼ 0.986 (not significant). The analysis also showed that PFS in patients with PDL1 positive with DEL 19 mutation was 15 months v/s7 months in L858R mutation(p ¼ 0.09). In PDL1 negative patients, PFS was 12 months v/s 10 monthsin Del 19 v/s L858R mutation. Conclusions: The present study showed a higher PDL1 positivity rate in EGFR mutant patients than what is previously reported. Also, the median PFS was not stastically different in PDL1 negative vs PDL1 positive patients. This is in contradiction to data previously presented. However, it could also be due to the fact that most of our patients were non smokers and could also represnt a geographic variation in PDL1 expression. Further studies are warranted to clarify this data.

e21110 Background: In extensive stage small-cell lung cancer (ES-SCLC) immune check-point inhibitors, atezolizumab and durvalumab, when combined with chemotherapy in the first-line setting show better efficacy than chemotherapy alone with safety profile similar as the adverse events of individual agents. Methods: We administered atezolizumab, etoposide and platinum, either carboplatin or cisplatin, in the first-line treatment in 24 newly diagnosed patients with ES-SCLC. Patients were treated until disease progression or unacceptable toxicity. Results: Out of 24 treated patients 13 were males and 11 were females, median age 61 (ranging from 44 to 80). Majority of patients were ECOG 1. Median number of atezolizumab doses was 8 (ranging from 2 to 11). We observed median progression free survival of 6 months (95%CI 4,28-7,72), while median overall survival was not reached. 10 patients (41%) are still undergoing treatment and 9 patients (37%) have died. Immune-related adverse events occurred in 6 patients (25%). Four patients developed pneumonitis (all of them CTCAE grade 2), two patients colitis (CTCAE grade 2 and 3) and one patient rash, CTCAE grade 3. Median treatment pause was 5 weeks (ranging from 3 to 12 weeks). There were no treatment discontinuations due to adverse events nor treatment related deaths. Conclusions: Atezolizumab combined with chemotherapy in ES-SCLC showed good tolerability and effectiveness in real world setting. Our data are consistent with published clinical trial data. There was no new safety signal in our patient cohort. Limitations of our report are small sample size and short follow-up time.

Non–small cell lung cancer (NSCLC) has become the best example of precision oncology’s impact on outcomes in everyday clinical practice, significantly changing the expectations of all stakeholders, including medical professionals, society, and most importantly, patients. Consequently, the implementation of the precision oncology concept in medical systems, in order to achieve optimal and proven curative effects in NSCLC, is imperative. In this study, we investigated the development, challenges, and results associated with the implementation of precision oncology in NSCLC on a national level in Croatia. We conducted a multicenter, retrospective, cross-sectional analysis on the total population of Croatian patients with metastatic lung cancer, on whose tumors specimen comprehensive genomic profiling (CGP) testing was performed during 2020 and 2021. A total of 48 patients were included in the study. CGP revealed clinically relevant genomic alterations (CRGA) in 37 patients (79%), with a median of 2 (IQR 1–3) CRGA per patient. From the panel of recommended tests, KRAS, MET, and EGFR were the most common alterations, detected in 16 (34%), 5 (11%), and 3 (6%) patients, respectively. CGP revealed additional targetable mutations in 29 (60%) patients who would not have been tested (and consequently, whose mutations would not have been detected) according to the existing everyday standard of practice in Croatia. The tumor mutational burden was reported as high (≥10 Muts/Mb) in 19 patients (40%). CGP analysis reported some kind of targeted therapy for 34 patients (72%). CGP revealed other potentially targetable mutations, and it also determined TMB to be high in a significant number of patients. In conclusion, when possible, CGP should be used as an upfront backbone diagnostic and treatment-oriented work-up in patients with NSCLC.