Consolidative Thoracic Radiation Therapy After First-Line Chemotherapy and Immunotherapy in Extensive-Stage Small Cell Lung Cancer: A Multi-Institutional Case Series

The effect and toxicity profile of consolidative or salvage thoracic radiotherapy following chemoimmunotherapy in patients with extensive stage small cell lung cancer

This study evaluated the efficacy and safety of thoracic radiotherapy (TRT) after first-line chemotherapy or chemoimmunotherapy in patients with extensive-stage small cell lung cancer (ES-SCLC), focusing on the impact of different TRT timing strategies (consolidative vs. salvage) on survival. A total of 54 ES-SCLC patients treated between January 2019 and July 2022 were retrospectively analyzed. Patients receiving consolidative TRT (cTRT) within 3 months after first-line treatment completion were compared to those receiving salvage TRT (sTRT) following disease progression. Primary endpoints included overall survival (OS), progression-free survival (PFS), locoregional-free survival (LRFS), and distant metastasis-free survival (DMFS); safety was a secondary endpoint. The cTRT group (n=41) showed significantly longer median OS (26.6 vs. 14.8 months, P=0.048), PFS (12.9 vs. 3.5 months, P< 0.0001), and DMFS (10.7 vs. 3.4 months, P= 0.0044) than the sTRT group (n=13). Multivariate analysis identified cTRT as an independent favorable prognostic factor. No significant differences in OS or LRFS were found between high-dose (≥50 Gy) and low-dose (<50 Gy) TRT. Hematologic and respiratory toxicities were the most common adverse events, with acceptable tolerability. In conclusion, consolidative TRT after chemoimmunotherapy significantly improves survival outcomes in ES-SCLC patients, and low-dose TRT may be a suitable option.

Current and future perspectives in extensive-stage small-cell lung cancer

Small-cell lung cancer (SCLC) is a highly aggressive and rapidly proliferative malignancy that has historically had limited therapeutic advancements. Recent advancements in the understanding of SCLC have led to attempts at subtyping the disease based on transcription factor characteristics, offering new insights into its biology and potential therapeutic targets. In addition, significant progress has been made in developing treatment regimens, providing new hope for improved patient outcomes. The introduction of immune checkpoint inhibitors, such as atezolizumab and durvalumab, in combination with traditional chemotherapy, has marked a significant advancement, demonstrating improved overall survival and progression-free survival compared to chemotherapy alone. Despite these advancements, the prognosis for extensive-stage SCLC (ES-SCLC), the more advanced form of SCLC, remains poor, highlighting the critical need for ongoing research and the development of novel therapeutic strategies. New treatment modalities, such as lurbinectedin and anti-Delta-like Canonical Notch Ligand 3 antibodies, are now included in the treatment options for refractory SCLC, and many more treatment strategies involving combination therapies are being studied. Advances in molecular profiling and the identification of biomarkers are aiding in the development of personalized treatment approaches. This review focuses on these recent advancements and emerging strategies in the treatment of ES-SCLC.

Comparison of metastasis and treatment patterns among different histopathologic types of lung cancer: analysis of 6 years of nationwide lung cancer cohort data in Korea

Background

Personalized management of stage IV lung cancer requires a deeper understanding of metastatic patterns and the potential benefits of localized treatments for each histologic type. This study aims to identify patterns of both intrathoracic and extrathoracic metastases across various histologic types of lung cancer using a nationwide Korean lung cancer database.

Methods

The study analyzed data from patients diagnosed with lung cancer between 2014 and 2019, sourced from the Korean Association of Lung Cancer Registry (KALC-R). Patients with stage IV lung cancer, indicated by M staging, were included to focus on metastatic patterns.

Results

The cohort included 7,562 stage IV lung cancer patients, with adenocarcinoma being the most prevalent histologic type, comprising 49.22% of cases (3,722 patients). M stage categorization showed that 27.3% were M1a, 56.3% M1b, 15.7% M1c, and 0.6% unspecified. The adenosquamous type had the highest proportion of patients with metastases in three or more organs (42.9%). Metastases to the liver and bones were consistently associated with decreased survival across histologic types. In adenocarcinoma, strong associations were observed between extrathoracic metastatic sites, particularly between bone and liver [odds ratio (OR) =3.93] and liver and adrenal glands (OR =2.85). Multivariate analysis revealed that patients receiving radiotherapy to lung lesions had significantly better overall survival (OS) [hazard ratio (HR) =0.68; 95% confidence interval (CI): 0.60-0.78; P<0.001] compared to those who did not. Radiotherapy to extrathoracic metastases also significantly improved survival (HR =0.84; 95% CI: 0.77-0.93; P<0.001).

Conclusions

Understanding metastasis patterns and treatment options specific to each lung cancer histologic type is essential for improving treatment strategies.

Clinical outcomes and synergistic effect between radiotherapy and immunotherapy in patients with extensive-stage small cell lung cancer: a real-world study

BACKGROUND

Patients with extensive-stage small cell lung cancer (ES-SCLC) experience significant therapeutic challenges and limited survival rates. This study aimed to investigate the efficacy of combining immunotherapy (IT) with chemotherapy (CT) for treating ES-SCLC and to explore the synergistic effect between radiotherapy (RT) and IT.

METHODS

This retrospective analysis examined patients with ES-SCLC who received treatment at three centers. Furthermore, propensity score-matched (PSM) analysis was conducted. The Kaplan‒Meier method and Cox proportional hazards regression were used to compare the survival outcomes.

RESULTS

A total of 257 eligible patients with ES-SCLC were included in the analysis. Among all patients, the median overall survival (mOS) was 18.0 m in the chemoimmunotherapy (CT + IT) group and 15.7 m in the CT group (p = 0.208). The median real-world progression-free survival (mrwPFS) was 7.7 m and 6.8 m (p = 0.043) in the CT + IT and CT group, respectively. Moreover, the mOS was 22.0 m in the chemoradiotherapy (CT + RT) group and 13.6 m in the CT group (p < 0.001). The mrwPFS was 7.4 m and 6.0 m (p = 0.175) in the CT + RT group and CT group, respectively. The multivariate analyses revealed that sex, liver metastasis and RT were independent prognostic factors for OS (p < 0.05), while liver metastasis and IT were found to be independent predictive factors of real-world progression-free survival (rwPFS) (p < 0.05). After PSM, the mOS was 23.2 m in the CT + IT group and 13.0 m in the CT group (p = 0.008). The mrwPFS was 7.3 m and 6.2 m (p = 0.096) in the CT + IT group and the CT group, respectively. Moreover, the mOS was 21.4 m in the CT + RT group and 12.5 m in the CT group (p < 0.001). The mrwPFS was 7.3 m and 5.2 m (p = 0.220) in the CT + RT group and the CT group, respectively. Additionally, our study revealed that in the PD-1 group, RT significantly improved patient survival (36.0 m vs. 15.8 m, p = 0.041).

CONCLUSION

An increasing number of treatment options are being explored for ES-SCLC, and CT is the cornerstone of treatment for this disease. Combining CT with IT and RT has demonstrated remarkable efficacy and excellent safety profiles, and such treatments are worthy of further exploration.

M, Gross CP, Slotman BJ, Chiang AC, Park HS. Differential Effect of Consolidative Thoracic Radiation Therapy in Extensive-Stage Small Cell Lung Cancer Based on Sex

Purpose

The landmark randomized trial on chest irradiation in extensive disease small cell lung cancer (CREST) demonstrated that consolidative thoracic radiation therapy (cTRT) improved overall (OS) and progression-free survival (PFS) after initial chemotherapy (chemo) in extensive-stage small cell lung cancer, with potentially increased benefit in women compared with men. It is unknown whether similar findings would apply after chemoimmunotherapy became the standard first-line treatment. In this analysis, we report national practice patterns and survival outcomes of cTRT according to patient sex.

Methods and Materials

We included patients from de-identified electronic health record-derived database diagnosed with stage IV small cell lung cancer (2014-2021) who completed 4 to 6 cycles of first-line systemic therapy (platinum-doublet chemotherapy or chemoimmunotherapy). We evaluated OS and PFS using multivariable Cox proportional hazards regression with receipt of cTRT as an independent variable and stratified by sex. As a sensitivity analysis, we weighted the models by the inverse probability of receiving cTRT.

Results

A total of 1227 patients were included (850 chemotherapy, 377 chemoimmunotherapy). There were no statistically significant differences in baseline characteristics between patients who did and did not receive cTRT. Among women, cTRT was associated with superior OS (adjusted hazard ratio [HR], 0.67; 95% CI, 0.52-0.87) and PFS (HR, 0.63; 95% CI, 0.49-0.82) compared with those not receiving cTRT. Conversely, no OS or PFS benefit with cTRT was observed in men (OS HR, 1.03; 95% CI, 0.80-1.31; PFS HR, 1.12; 95% CI, 0.85-1.47). Findings were similar in weighted analyses.

Conclusions

The survival efficacy of cTRT may be moderated by sex, with female patients appearing more likely to benefit than male patients. These findings reflect sex-based survival trends with similar effect sizes to those observed in the CREST trial. Although the underpinnings of this association need to be elucidated, stratification by sex should be considered for randomized-controlled trials studying cTRT in extensive-stage small cell lung cancer.

Intrathoracic Progression Is Still the Most Dominant Failure Pattern after First-Line Chemo-immunotherapy in Extensive-Stage Small-Cell Lung Cancer: Implications for Thoracic Radiotherapy

PURPOSE

This study aimed to compare the failure patterns before and after the introduction of immunotherapy and to determine the role of thoracic radiotherapy (TRT) in extensive-stage small-cell lung cancer (ES-SCLC) treatment.

MATERIALS AND METHODS

We retrospectively reviewed 294 patients with ES-SCLC, of which 62.2% underwent chemotherapy alone, 13.3% underwent chemotherapy followed by consolidative TRT (TRT group), and 24.5% underwent chemotherapy with immune checkpoint inhibitor (ICI group). We performed propensity-score matching (PSM) to compare each treatment group.

RESULTS

The median follow-up duration was 10.4 months. At the first relapse, in the cohort showing objective response, the proportion of cases showing intrathoracic progression was significantly lower in the TRT group (37.8%) than in the chemotherapy-alone (77.2%, p < 0.001) and the ICI (60.3%, p=0.03) groups. Furthermore, in the subgroup analysis, TRT showed benefits related to intrathoracic progression-free survival (PFS) in comparison with ICI in patients with less than two involved extrathoracic sites (p=0.008) or without liver metastasis (p=0.02) or pleural metastasis (p=0.005) at diagnosis. After PSM, the TRT group showed significantly better intrathoracic PFS than both chemotherapy-alone and ICI groups (p < 0.001 and p=0.04, respectively), but showed no significant benefit in terms of PFS and overall survival in comparison with the ICI group (p=0.17 and p=0.31, respectively).

CONCLUSION

In ES-SCLC, intrathoracic progression was the most dominant failure pattern after immunotherapy. In the era of chemoimmunotherapy, consolidative TRT can still be considered a useful treatment strategy for locoregional control.

Efficacy and safety of thoracic radiotherapy in extensive-stage small-cell lung cancer patients receiving first-line immunotherapy plus chemotherapy: a propensity score matched multicentre retrospective analysis

BACKGROUND

Platinum-etoposide chemotherapy combined with immune checkpoint inhibitors (ICIs) has been recommended as the first-line standard treatment for extensive-stage small-cell lung cancer (ES-SCLC). However, the effect of thoracic radiotherapy (TRT) on these patients is still unknown. This study aimed to evaluate the efficacy and safety of TRT for ES-SCLC patients who responded to first-line ICIs and chemotherapy (CHT).

METHODS

Patients who received 4 to 6 cycles of ICIs and CHT as first-line therapy at three hospitals between 2018 and 2022 were included in the analysis. All patients were divided into two groups based on whether they received TRT as first-line treatment, and propensity score matching (PSM) was performed to ensure that the characteristics of two groups were well-balanced. The primary endpoints were overall survival (OS) and progression-free survival (PFS), and the secondary endpoint was toxic effects.

RESULTS

A total of 276 patients were included, and the median follow-up time was 22.3 (range, 4.0-53.73) months. After PSM, 197 patients were further analysed, and 99 of whom received TRT. The baseline characteristics were well-balanced between patients in the TRT and non-TRT groups. There were significant differences in PFS between the TRT and non-TRT groups, with the median PFS of 10.76 and 7.63 months, respectively (P = 0.014). Significantly improved OS was observed in the TRT group (21.67 vs. 16.6 months, P = 0.009). In addition, the use of TRT was an independent prognostic factor for PFS and OS of ES-SCLC patients receiving ICIs plus CHT. In terms of safety, no significant increase of any grades adverse event (AE) (P = 0.874) and G3-4 AE (P = 0.909) was observed for patients receiving TRT. Radiation esophagitis, gastrointestinal and hematologic toxicities were the most common AEs in TRT group, which were tolerable. And high-dose radiotherapy was associated with higher incidence of pneumonitis.

CONCLUSION

Addition of TRT showed significant survival benefits and well tolerability in ES-SCLC patients receiving platinum-etoposide CHT and ICIs, which could be a feasible first-line treatment strategy for ES-SCLC patients.

Chinese clinical practice guidelines for the prevention and treatment of radiation-induced esophagitis

Acute radiation-induced esophagitis is a common complication of radiotherapy for esophageal, lung, and other malignancies. Therefore, understanding the diagnosis, grading, risk factors, prevention, and treatment of radiation-induced esophagitis is essential. Currently, there are few consensuses and guidelines on radiation-induced esophagitis worldwide, mainly the American College of Gastroenterology (ACG) clinical guideline: evidenced based approach to the diagnosis and management of esophageal eosinophilia and eosinophilic esophagitis (EoE) and the Digestive Endoscopy Society of Chinese Medical Association's "Guidelines for the Diagnosis and Treatment of Reflux Esophagitis." However, no consensus or guidelines specifically addressing radiation-induced esophagitis have been established. Efforts have been made to organize experts to draft Chinese consensus or guidelines, but the recommendations in these guidelines also vary owing to differences in expert backgrounds. The clinical practice guidelines presented herein were developed for the first time with the joint participation of Chinese radiotherapy experts. Drugs and methods with clinical significance were selected by reviewing and summarizing the prevention and treatment of radiation-induced esophagitis and combining them with China's national conditions. After multiple rounds of discussion and revision, clinical practice guidelines were established in line with the needs of Chinese clinicians, providing useful clinical guidance for the prevention and treatment of radiation-induced esophagitis.

Clinical insights into small cell lung cancer: Tumor heterogeneity, diagnosis, therapy, and future directions

Small cell lung cancer (SCLC) is characterized by rapid growth and high metastatic capacity. It has strong epidemiologic and biologic links to tobacco carcinogens. Although the majority of SCLCs exhibit neuroendocrine features, an important subset of tumors lacks these properties. Genomic profiling of SCLC reveals genetic instability, almost universal inactivation of the tumor suppressor genes TP53 and RB1, and a high mutation burden. Because of early metastasis, only a small fraction of patients are amenable to curative-intent lung resection, and these individuals require adjuvant platinum-etoposide chemotherapy. Therefore, the vast majority of patients are currently being treated with chemoradiation with or without immunotherapy. In patients with disease confined to the chest, standard therapy includes thoracic radiotherapy and concurrent platinum-etoposide chemotherapy. Patients with metastatic (extensive-stage) disease are treated with a combination of platinum-etoposide chemotherapy plus immunotherapy with an anti-programmed death-ligand 1 monoclonal antibody. Although SCLC is initially very responsive to platinum-based chemotherapy, these responses are transient because of the development of drug resistance. In recent years, the authors have witnessed an accelerating pace of biologic insights into the disease, leading to the redefinition of the SCLC classification scheme. This emerging knowledge of SCLC molecular subtypes has the potential to define unique therapeutic vulnerabilities. Synthesizing these new discoveries with the current knowledge of SCLC biology and clinical management may lead to unprecedented advances in SCLC patient care. Here, the authors present an overview of multimodal clinical approaches in SCLC, with a special focus on illuminating how recent advancements in SCLC research could accelerate clinical development.

Safety and efficacy of thoracic radiotherapy combined with chemo-immunotherapy in patients with extensive-stage small cell lung cancer: a multicenter retrospective analysis

Background

Immunotherapy has greatly increased the survival time of patients with extensive-stage small cell lung cancer (ES-SCLC), and is now a standard first-line treatment for these patients. Increasing evidence suggests a possible synergistic effect between immunotherapy and radiotherapy, yet there is a paucity of evidence regarding the efficacy and safety of thoracic radiotherapy (TRT) combined with chemo-immunotherapy for ES-SCLC.

Methods

The medical records of 78 consecutive patients with ES-SCLC who received TRT in combination with chemo-immunotherapy at Jinling Hospital and Jiangsu Cancer Hospital from January 2019 to January 2023 were retrospectively reviewed. The median overall survival (mOS) time and median progression-free survival (mPFS) time were used to evaluate efficacy, and the incidence of adverse events (AEs) was used to evaluate safety.

Results

The median follow-up time was 31.9 months, the objective response rate (ORR) was 59%, and the disease control rate (DCR) was 89.8%. The mOS time was 20.0 months, and the 6-month OS rate was 95%. The mPFS time was 9.2 months, and the 6-month PFS rate was 78%. There were no treatment-related deaths. The incidence of pneumonitis was 23.1%, the incidence of radiation esophagitis was 5.1%, and 2 patients experienced high-grade pneumonitis. Primary liver metastasis was a predictor of poor OS and PFS. Patients who received consolidative TRT after chemo-immunotherapy experienced more benefit than those who received TRT as palliative or salvage treatment for superior vena cava syndrome or disease progression.

Conclusions

TRT is a feasible treatment for patients who receive chemo-immunotherapy for the management of ES-SCLC in consideration of its considerable efficacy and tolerable safety risk. This treatment is especially useful for patients without primary liver metastasis and who receive consolidative TRT after chemo-immunotherapy. Large-scale prospective studies are needed to confirm the efficacy and safety of this treatment modality.

Efficacy and safety of thoracic radiotherapy for extensive stage small cell lung cancer after immunotherapy in real world

The immunotherapy combined chemotherapy has been the standard treatment strategy for extensive-stage small lung cancer (ES-SCLC). The CREST trial reported consolidative thoracic radiotherapy (cTRT) improved overall survival (OS) for ES-SCLC with intrathoracic residual after chemotherapy. In this study, patients with ES-SCLC who received immunotherapy were assigned to receive either TRT or no TRT. TRT significantly improved progression-free survival (PFS), local recurrence-free survival (LRFS) and OS with well tolerated toxicity. Further sub-cohort analysis, TRT significantly improved LRFS in patients with oligo-metastasis and without liver metastasis.

Progress in radiotherapy for small-cell lung cancer

Small-cell lung cancer (SCLC) is a highly aggressive neuroendocrine tumor that is prone to spread extensively. Compared to non-small-cell lung cancer (NSCLC), SCLC treatment progresses slowly. Although SCLC is highly sensitive to chemotherapy during the initial treatment, most patients still experience resistance and recurrence after receiving chemotherapy. A meta-analysis demonstrated that thoracic radiotherapy (TRT) improves overall survival in SCLC. The results of the CALGB and CONVERT trials provide evidence for the efficacy of once-daily high-dose TRT. TRT at 60 Gy administered twice daily significantly improved survival without increasing toxicity. The long-standing debate over the optimal timing of radiotherapy has not been fully resolved. SBRT has excellent local control rates and is a safe and effective treatment option for patients with stage I or II SCLC. Prophylactic cranial irradiation (PCI) is used to reduce treatment-related neurotoxicity to the extent that there has been a recent discussion on whether magnetic resonance imaging (MRI) monitoring can replace PCI. Radiotherapy combined with immunotherapy significantly improves the survival rate of patients with NSCLC; however, its clinical effectiveness has not been systematically explored in patients with SCLC. Therefore, we summarize the evolving therapeutic strategies, (TRT for limited stage-SCLC and consolidative TRT for extensive stage-SCLC) and improved radiotherapy techniques (role of SBRT in stage I or II node-negative SCLC, progress of PCI, and stereotactic radiosurgery), and discuss the possibilities and prospects of radiotherapy combined with immunotherapy for SCLC.

The role of thoracic consolidative radiotherapy in the setting of immunotherapy in extensive stage small cell lung cancer

The improvement in treatment strategies and outcomes in small cell lung cancer (SCLC) has lagged behind other cancers. The addition of immune checkpoint inhibitors (ICIs), durvalumab and atezolizumab, to the platinum-based chemotherapy in frontline setting has improved the survival in extensive stage SCLC, (ES-SCLC), albeit modestly, and is now the new standard of care. Prior to advent of immunotherapy into the therapeutic armamentarium in ES-SCLC, consolidative thoracic radiotherapy (TRT) was associated with improved thoracic control and survival outcomes. In the era of ICIs, the role of TRT is not well defined, chiefly because TRT was not incorporated in any immunotherapy trials, secondly due to concerns regarding the increased risks of pneumonitis, and finally uncertain magnitude of benefit with this combined approach. In principle, radiation can increase in the immunogenicity of tumor and hence the activity of immune checkpoint blockade, thereby increasing efficacy both locally and distantly. Such an approach has been promising in non-small cell lung cancer with ICIs improving outcomes after concurrent chemoradiation, but remains unanswered in ES-SCLC. It is, thus, possible that the modest improvement in survival by addition of ICIs to chemotherapy in ES-SCLC can be further improved by the incorporation of consolidative TRT in selected patients. Several early phase trials and retrospective studies have suggested that such an approach may be feasible and safe. Prospective trials are ongoing to answer whether adding radiation therapy to chemoimmunotherapy will improve outcomes in ES-SCLC.

Real-world outcomes of PD-L1 inhibitors combined with thoracic radiotherapy in the first-line treatment of extensive stage small cell lung cancer

BACKGROUND

The CREST study showed that the addition of thoracic radiotherapy (TRT) could improve the survival rate in patients with extensive stage small cell lung cancer (ES-SCLC), but whether TRT can bring survival benefit in the era of immunotherapy remains controversial. This study aimed to explore the efficacy and safety of adding TRT to the combination of PD-L1 inhibitors and chemotherapy.

METHODS

The patients who received durvalumab or atezolizumab combined with chemotherapy as the first-line treatment of ES-SCLC from January 2019 to December 2021 were enrolled. They were divided into two groups, based on whether they received TRT or not. Propensity score matching (PSM) with a 1:1 ratio was performed. The primary endpoints were progression-free survival (PFS), overall survival (OS) and safety.

RESULTS

A total of 211 patients with ES-SCLC were enrolled, of whom 70 (33.2%) patients received standard therapy plus TRT as first-line treatment, and 141 (66.8%) patients in the control group received PD-L1 inhibitors plus chemotherapy. After PSM, a total of 57 pairs of patients were enrolled in the analysis. In all patients, the median PFS (mPFS) in the TRT and non-TRT group was 9.5 and 7.2 months, respectively, with HR = 0.59 (95%CI 0.39-0.88, p = 0.009). The median OS (mOS) in the TRT group was also significantly longer than that in the non-TRT group (24.1 months vs. 18.5 months, HR = 0.53, 95%CI 0.31-0.89, p = 0.016). Multivariable analysis showed that baseline liver metastasis and the number of metastases ≥ 3 were independent prognostic factors for OS. Addition of TRT increased the incidence of treatment-related pneumonia (p = 0.018), most of which were grade 1-2.

CONCLUSIONS

Addition of TRT to durvalumab or atezolizumab plus chemotherapy significantly improves survival in ES-SCLC. Although it may leads to increased incidence of treatment-related pneumonia, a majority of the cases can be relieved after symptomatic treatment.

Potential Applications of Nanoparticles in Improving the Outcome of Lung Cancer Treatment

Lung cancer is managed using conventional therapies, including chemotherapy, radiation therapy, or a combination of both. Each of these therapies has its own limitations, such as the indiscriminate killing of normal as well as cancer cells, the solubility of the chemotherapeutic drugs, rapid clearance of the drugs from circulation before reaching the tumor site, the resistance of cancer cells to radiation, and over-sensitization of normal cells to radiation. Other treatment modalities include gene therapy, immunological checkpoint inhibitors, drug repurposing, and in situ cryo-immune engineering (ICIE) strategy. Nanotechnology has come to the rescue to overcome many shortfalls of conventional therapies. Some of the nano-formulated chemotherapeutic drugs, as well as nanoparticles and nanostructures with surface modifications, have been used for effective cancer cell killing and radio sensitization, respectively. Nano-enabled drug delivery systems act as cargo to deliver the sensitizer molecules specifically to the tumor cells, thereby enabling the radiation therapy to be more effective. In this review, we have discussed the different conventional chemotherapies and radiation therapies used for inhibiting lung cancer. We have also discussed the improvement in chemotherapy and radiation sensitization using nanoparticles.

Is consolidative thoracic radiotherapy of extensive-stage small cell lung cancer still beneficial in the era of immunotherapy? A retrospective analysis

PURPOSE

Extensive-stage small cell lung cancer (ES-SCLC) carries a dismal prognosis. The benefit of consolidative thoracic radiotherapy (TR) after first-line chemoimmunotherapy with PD-L1 inhibitors in this setting remains unclear. As TR can improve overall survival (OS) after conventional chemotherapy, we retrospectively analyzed OS of an inhouse cohort treated either with TR or with chemoimmunotherapy alone.

METHODS

A total of 41 patients treated with chemoimmunotherapy with PD-L1 inhibitors (atezolizumab or durvalumab) for ES-SCLC at our hospital since 2019 were analyzed. TR was administered in 10 fractions of 3 Gy. Patient characteristics, number of immunotherapy cycles received, brain irradiation, and presence of hepatic and cerebral metastasis at diagnosis were assessed. Primary endpoint was OS after first diagnosis.

RESULTS

Consolidative TR was associated with a significantly longer OS than systemic therapy alone (1-year OS 78.6% and 2‑year OS 37.1% vs. 1‑year OS 39.7% and 2 years not reached, p = 0.019). With regard to radiotherapy indication, survival at 1 year was 88.9% (log-rank p = 0.016) for patients receiving consolidative TR. For patients receiving TR in case of progression, 1‑year survival was 66.7%. Hepatic and cerebral metastasis at first diagnosis had no significant effect on OS.

CONCLUSION

TR was significantly associated with longer OS. The survival benefit of TR was most pronounced for consolidative radiotherapy after initial chemoimmunotherapy compared to TR in case of progression. Although retrospective findings need to be interpreted with caution, in the absence of prospective data, our findings provide a basis for offering consolidative TR in the era of chemoimmunotherapy.

First-line atezolizumab/durvalumab plus platinum-etoposide combined with radiotherapy in extensive-stage small-cell lung cancer

BACKGROUND

Immunotherapy has made significant advances in the treatment of extensive-stage small-cell lung cancer (ES-SCLC), but data in combination with radiotherapy are scarce. This study aims to assess the safety and efficacy of chemoimmunotherapy combined with thoracic radiotherapy in patients with ES-SCLC.

METHODS

This single-center retrospective study analyzed patients with ES-SCLC who received standard platinum-etoposide chemotherapy combined with atezolizumab or durvalumab immunotherapy as induction treatment, followed by consolidative thoracic radiotherapy (CTRT) before disease progression in the first-line setting. Adverse events during radiotherapy with or without maintenance immunotherapy and survival outcomes were assessed.

RESULTS

Between December 2019 and November 2021, 36 patients with ES-SCLC were identified to have received such treatment modality at one hospital. The number of metastatic sites at diagnosis was 1-4. The biological effective dose of CTRT ranged from 52 to 113 Gy. Only two patients (6%) developed grade 3 toxic effect of thrombocytopenia, but none experienced grade 4 or 5 toxicity. Four patients developed immune-related pneumonitis during the induction treatment period but successfully completed later CTRT. The rate of radiation-related pneumonitis was 8% with grades 1-2 and well tolerated. The median progression-free survival (PFS) was 12.8 months, but the median overall survival (OS) was not determined. The estimated 1-year OS was 80.2% and 1-year PFS was 53.4%.

CONCLUSIONS

Immunotherapy combined with CTRT for ES-SCLC is safe and has ample survival benefit.

Thoracic irradiation as consolidation therapy in patients with extensive-stage small cell lung cancer

PURPOSE OF REVIEW

Small cell lung cancer (SCLC) is marked by an exceptionally high proliferative rate and poor prognosis. Given its high propensity to metastasize, nearly two-thirds of SCLC patients are diagnosed with extensive-stage (ES) disease when surgery is not a treatment option anymore. Over several decades, only minimal changes have been made in the therapeutic armamentarium of ES-SCLC. Recently, however, several new therapeutic avenues were defined, thus renewing the hope for patients with this recalcitrant cancer. Here, we present an overview of the most current therapeutic advances in ES-SCLC focusing in particular on consolidative thoracic radiation therapy (cTRT) and chemo-immunotherapy.

RECENT FINDINGS

The incorporation of immunotherapy in the standard-of-care of ES-SCLC patients and the resulting outcomes are both a remarkable hallmark of progress and a disappointment. Indeed, chemo-immunotherapy with or without cTRT and prophylactic cranial irradiation contributes to longer survival outcomes with minimal toxicity rates in well selected and properly monitored patients. Nevertheless, the gain in overall survival is still modest relative to that seen in many other solid tumors.

SUMMARY

Despite the encouraging results, further clinical trials are needed to determine the efficacy and safety of these therapeutic approaches, and moreover, to identify new predictive biomarkers of response.

Radiation therapy for extensive-stage small-cell lung cancer in the era of immunotherapy

Unlike non-small-cell lung cancer (NSCLC), the progression of small-cell lung cancer (SCLC) is slow. Extensive-stage SCLC (ES-SCLC) is a serious threat to human health, with a 5-year survival rate of <7%. Chemotherapy has been the first-line treatment for the past 30 years. The anti-PD-L1 checkpoint blockades durvalumab and atezolizumab have greatly prolonged overall survival and have become the standard first-line therapy for ES-SCLC since the CASPIAN and IMpower133 trials. In the era of chemotherapy, radiation therapy (RT), including thoracic radiation therapy (TRT) and brain radiation therapy (BRT), has shown clinical effects in randomized and retrospective studies on ES-SCLC. RT-immunotherapy has shown exciting synergistic effects in NSCLC. For ES-SCLC, the clinical effects of combining TRT/BRT with immunotherapy have not yet been systematically explored. In this review, we found that studies on RT-immunotherapy in ES-SCLC are relatively few and limited to early phase studies focusing on toxicity. The efficacy and safety profiles of early phase studies encourage prospective clinical trials. In this review, we discuss the best population, optimum TRT dose, proper TRT time, and strategies for reducing radiation-induced neurotoxicity. Furthermore, we suggest that biomarkers and patient performance status should be fully assessed before RT-immunotherapy treatment. Prospective trials are needed to provide more evidence for RT-immunotherapy applications in ES-SCLC.