Stereotactic ablative radiation therapy versus conventionally fractionated radiation therapy for stage I small cell lung cancer

Imaging Follow-Up of Nonsurgical Therapies for Lung Cancer: AJR Expert Panel Narrative Review

Lung cancer continues to be the most common cause of cancer-related death worldwide. In the past decade, with the implementation of lung cancer screening programs and advances in surgical and nonsurgical therapies, the survival of patients with lung cancer has increased, as has the number of imaging studies that these patients undergo. However, most patients with lung cancer do not undergo surgical re-section, because they have comorbid disease or lung cancer in an advanced stage at diagnosis. Nonsurgical therapies have continued to evolve with a growing range of systemic and targeted therapies, and there has been an associated evolution in the imaging findings encountered at follow-up examinations after such therapies (e.g., with respect to posttreatment changes, treatment complications, and recurrent tumor). This AJR Expert Panel Narrative Review describes the current status of nonsurgical therapies for lung cancer and their expected and unexpected imaging manifestations. The goal is to provide guidance to radiologists regarding imaging assessment after such therapies, focusing mainly on non-small cell lung cancer. Covered therapies include systemic therapy (conventional chemotherapy, targeted therapy, and immunotherapy), radiotherapy, and thermal ablation.

Stereotactic Body Radiotherapy (SBRT) in Very Limited-Stage Small Cell Lung Cancer (VLS-SCLC)

Small cell lung cancer (SCLC) is an aggressive neuroendocrine tumour with metastatic propensity. Stereotactic body radiation therapy (SBRT) is an emerging therapeutic option for SCLC, despite limited supporting evidence. By evaluating the use of SBRT in very limited stage (VLS) SCLC at our institution, we aimed to contribute to the existing knowledge in this area while establishing a basis for further research. We performed a retrospective review of all cases of VLS-SCLC treated with SBRT between 2013 and 2020. Baseline demographics, diagnostic, and treatment information were collected. The primary outcome was overall survival (OS). We identified 46 patients with pathologically confirmed VLS-SCLC; 25 were treated with SBRT, and the remainder received either surgery, conventional radiation therapy, chemotherapy, or palliative-intent therapy. After a median follow-up of 23.7 months, 44% of the patients had died; the median OS was of 24.4 months for the SBRT cohort and 67.0 months for the curative intent non-SBRT cohort. The difference in disease recurrence and survival between cohorts was underpowered and not statistically significant. Higher baseline ECOG and comorbidity was noted in the SBRT cohort.

Cost-effectiveness of stereotactic body radiotherapy versus conventional radiotherapy for the treatment of surgically ineligible stage I non-small cell lung cancer in the Brazilian public health system

Background

The Brazilian public health system does not pay for the use of Stereotactic body radiotherapy (SBRT) due to its costs and the absence of cost-effectiveness analysis showing its benefit. The present study aims to evaluate whether the SBRT is a more cost-effective strategy than the conventional fractionated radiotherapy (CFRT) for surgically ineligible stage I non-small cell lung cancer (NSCLC) in the Brazilian public health system.

Methods

Adopting the perspective of the Brazilian Unified Healthcare System (SUS) as the payer, a Markov model with a lifetime horizon was built to delineate the health states for a cohort of 75-years-old men with medically inoperable NSCLC after treatment with SBRT or CFRT. Transition probabilities and health states utilities were adapted from the literature. Costs were based on the public health system reimbursement values and simulated in the private sector.

Findings

The SBRT strategy results in more quality-adjusted life-year (QALYs) and costs with an incremental cost-effectiveness ratio (ICER) of R$ 164.86 (U$ 65.16) per QALY and R$ 105 (U$ 41.50) per life-year gained (LYG). This strategy was cost-effective, considering a willingness-to-pay of R$ 25,000 (U$ 9,881.42) per QALY. The net monetary benefit (NMB) was approximately twice higher. The outcomes were confirmed with 92% of accuracy in the probabilistic sensitivity analysis.

Interpretation

Using a threshold of R$25,000 per QALY, SBRT was more cost-effective than CFRT for NSCLC in a public health system of an upper-middle-income country. SBRT generates higher NMB than CFRT, which could open the opportunity to incorporate new technologies.

Funding

Varian Medical Systems.

New perspectives in the management of small cell lung cancer

The treatment of small cell lung cancer (SCLC) is a challenge for all specialists involved. New treatments have been added to the therapeutic armamentarium in recent months, but efforts must continue to improve both survival and quality of life. Advances in surgery and radiotherapy have resulted in prolonged survival times and fewer complications, while more careful patient selection has led to increased staging accuracy. Developments in the field of systemic therapy have resulted in changes to clinical guidelines and the management of patients with advanced disease, mainly with the introduction of immunotherapy. In this article, we describe recent improvements in the management of patients with SCLC, review current treatments, and discuss future lines of research.

Stereotactic ablative radiotherapy in T1-2N0M0 small cell lung cancer: A systematic review and meta-analysis

OBJECTIVES

Stereotactic ablative radiotherapy (SABR) is used to treat inoperable early-stage, node-negative small cell lung cancer (SCLC). We performed a systematic review and meta-analysis of the literature on SABR for T1-2N0M0 SCLC to summarize outcomes including local control (LC), overall survival (OS), recurrence rates, and toxicity.

MATERIALS AND METHODS

This study was conducted in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) and MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines. A systematic review of PubMed and EMBASE (inception to April 2021) was conducted. Two authors independently reviewed articles for inclusion and extracted study-level data. Random-effects meta-analysis was conducted using R (version 3.6.2) at a significance threshold of 0.05.

RESULTS

Eleven studies were identified in the systematic review and seven (399 patients) were selected for meta-analysis. Inoperability was noted as the indication for SABR in 94% (75-100%) of patients. Median follow-up and tumor size were 19.5 months (11.9-32) and 24 mm (19-29), respectively. Chemotherapy and PCI use rates were 44.1% (95% confidence interval [CI], 27.0-61.9%) and 13.8% (95% CI, 0.4-41.2%), respectively. Local control was 97.3% (95% CI, 92.3-99.8%) at 1 year and 95.7% (95% CI, 74.2-100.0%) at 2 years. Overall survival was 86.3% (95% CI, 74.4-94.9%) at 1 year and 63.7% (95% CI, 45.7-79.9%) at 2 years. Nodal and distant recurrence rates were 17.8% (95% CI, 7.5-31.2%) and 26.9% (95% CI, 7.4-53.0%), respectively. The rates of grade 1, grade 2, and grade 3 toxicity (CTCAE) were 12.6% (95% CI, 6.7-19.9%), 6.7% (95% CI, 3.3-11.2%), and 1.4% (95% CI, 0.0-5.3%), respectively. No grade 4 or 5 events were observed across the studies.

CONCLUSION

SABR for inoperable early-stage, node-negative SCLC is locally effective with limited toxicity. Prospective studies are required to further evaluate the role of SABR for patients at higher risk of toxicity with surgery or combined chemoradiation.

Imaging of the post-radiation chest in lung cancer

Radiation therapy using conventional fractionated external-beam or high-precision dose techniques including three-dimensional conformal radiotherapy, stereotactic body radiation therapy, intensity-modulated radiation therapy, and proton therapy, is a key component in the treatment of patients with lung cancer. Knowledge of the radiation technique used, radiation treatment plan, expected temporal evolution of radiation-induced lung injury and patient-specific parameters, such as previous radiotherapy, concurrent chemoradiotherapy, and/or immunotherapy, is important in imaging interpretation. This review discusses factors that affect the development and severity of radiation-induced lung injury and its radiological manifestations with emphasis on the differences between conventional radiation and high-precision dose radiotherapy techniques.

Thoracic radiotherapy in small cell lung cancer-a narrative review

Small-cell lung cancer (SCLC) represents 10–15% of all lung cancers and has a poor prognosis. Thoracic radiotherapy plays a central role in current SCLC management. Concurrent chemoradiotherapy (CTRT) is the standard of care for localised disease (stage I−III, limited-stage, LS). Definitive thoracic radiotherapy may be offered in metastatic patients (stage IV, extensive stage, ES-SCLC) after chemotherapy. For LS-SCLC, the gold standard is early accelerated hyperfractionated twice-daily CTRT (4 cycles of cisplatin etoposide, starting with the first or second chemotherapy cycle). Modern radiation techniques should be used with involved-field radiotherapy based on baseline CT and PET/CT scans. In ES-SCLC, thoracic radiotherapy should be discussed in cases of initial bulky mediastinal disease/residual thoracic disease not progressing after induction chemotherapy. This strategy was however not assessed in recent trials establishing chemo-immunotherapy as the standard first line treatment in ES-SCLC. Future developments include technical radiotherapy advances and the incorporation of new drugs. Thoracic irradiation is delivered more precisely given technical developments (IMRT, image-guided radiotherapy, stereotactic radiotherapy), reducing the risks of severe adverse events. Stereotactic ablative radiotherapy may be discussed in rare early stage (T1 to 2, N0) inoperable patients. A number of current clinical trials are investigating immunoradiotherapy. In this review, we highlight the current role of thoracic radiotherapy and describe ongoing research in the integration of biological surrogate markers, advanced radiotherapy technologies and novel drugs in SCLC patients.

GOECP/SEOR radiotherapy guidelines for small-cell lung cancer

Small cell lung cancer (SCLC) accounts for approximately 20% of all lung cancers. The main treatment is chemotherapy (Ch). However, the addition of radiotherapy significantly improves overall survival (OS) in patients with non-metastatic SCLC and in those with metastatic SCLC who respond to Ch. Prophylactic cranial irradiation reduces the risk of brain metastases and improves OS in both metastatic and non-metastatic patients. The 5-year OS rate in patients with limited-stage disease (non-metastatic) is slightly higher than 30%, but less than 5% in patients with extensive-stage disease (metastatic). The present clinical guidelines were developed by Spanish radiation oncologists on behalf of the Oncologic Group for the Study of Lung Cancer/Spanish Society of Radiation Oncology to provide a current review of the diagnosis, planning, and treatment of SCLC. These guidelines emphasise treatment fields, radiation techniques, fractionation, concomitant treatment, and the optimal timing of Ch and radiotherapy. Finally, we discuss the main indications for reirradiation in local recurrence.

Curcumin Inhibits the Migration and Invasion of Non-Small-Cell Lung Cancer Cells Through Radiation-Induced Suppression of Epithelial-Mesenchymal Transition and Soluble E-Cadherin Expression

Radiotherapy has been reported to cause cancer metastasis. Thus, a new strategy for radiotherapy must be developed to avoid this side effect. A549 cells were exposed to radiation to induce an epithelial-mesenchymal transition (EMT) cell model. Real-time PCR and western blotting were used to detect mRNA and protein expression levels, and Transwell invasion and wound healing assays were used to detect cell migration and invasion. ELISA was used to detect soluble E-cadherin (sE-cad) secretion. siRNA was used to silence MMP9 expression. The results show that A549R cells exhibited an EMT phenotype with increased E-cadherin, N-cadherin, Snail, Slug, vimentin and Twist expression and decreased pan-keratin expression. sE-cad levels were increased in A549R cells and in the serum of NSCLC patients with distant metastasis. Exogenous sE-cad treatment and sE-cad overexpression promoted A549R and A549 cell migration and invasion. In contrast, blocking sE-cad attenuated A549 cell migration and invasion. Curcumin inhibited sE-cad expression and reversed EMT induced by radiation. Furthermore, curcumin suppressed sE-cad-enhanced A549 and A549R cell migration and invasion. Curcumin inhibited MMP9 expression, and silencing MMP9 suppressed sE-cad expression. Taken together, we found a nonclassic EMT phenomenon induced by radiation. Curcumin inhibits NSCLC migration and invasion by suppressing radiation-induced EMT and sE-cad expression by decreasing MMP9 expression.

Reduced Fractionation in Lung Cancer Patients Treated with Curative-intent Radiotherapy during the COVID-19 Pandemic

Patients treated with curative-intent lung radiotherapy are in the group at highest risk of severe complications and death from COVID-19. There is therefore an urgent need to reduce the risks associated with multiple hospital visits and their anti-cancer treatment. One recommendation is to consider alternative dose-fractionation schedules or radiotherapy techniques. This would also increase radiotherapy service capacity for operable patients with stage I-III lung cancer, who might be unable to have surgery during the pandemic. Here we identify reduced-fractionation for curative-intent radiotherapy regimes in lung cancer, from a literature search carried out between 20/03/2020 and 30/03/2020 as well as published and unpublished audits of hypofractionated regimes from UK centres. Evidence, practical considerations and limitations are discussed for early-stage NSCLC, stage III NSCLC, early-stage and locally advanced SCLC. We recommend discussion of this guidance document with other specialist lung MDT members to disseminate the potential changes to radiotherapy practices that could be made to reduce pressure on other departments such as thoracic surgery. It is also a crucial part of the consent process to ensure that the risks and benefits of undergoing cancer treatment during the COVID-19 pandemic and the uncertainties surrounding toxicity from reduced fractionation have been adequately discussed with patients. Furthermore, centres should document all deviations from standard protocols, and we urge all colleagues, where possible, to join national/international data collection initiatives (such as COVID-RT Lung) aimed at recording the impact of the COVID-19 pandemic on lung cancer treatment and outcomes.

Current Management and Progress in Radiotherapy for Small Cell Lung Cancer

Radiotherapy (RT) and chemotherapy continue to be widely utilized in small cell lung cancer (SCLC) management. In most limited stage (LS)-SCLC cases, the standard initial therapy remains concurrent chemoradiotherapy (CRT), typically with an etoposide and platinum-based regimen. Hyperfractionated twice daily (BID) RT remains the standard of care, though conventional daily (QD) RT is now a viable alternative supported by randomized evidence. In LS-SCLC patients who experienced good response to CRT, prophylactic cranial irradiation (PCI) remains the standard of care. Brain imaging, ideally with MRI, should be performed prior to PCI to screen for clinically apparent brain metastases that may require a higher dose of cranial irradiation. Platinum doublet chemotherapy alone is the historic standard initial therapy in extensive stage (ES)-SCLC. Addition of immunotherapy such as atezolizumab and durvalumab to chemotherapy is now recommended after their benefits were demonstrated in recent trials. In patients with response to chemotherapy, consolidation thoracic RT and PCI could be considered, though with caveats. Emergence of hippocampal avoidance cranial irradiation and SRS in SCLC patients may supplant whole cranial irradiation as future standards of care. Incorporation of novel systemic therapies such as immunotherapies has changed the treatment paradigm and overall outlook of patients with SCLC. This narrative review summarizes the current state, ongoing trials, and future directions of radiotherapy in management of SCLC.

Software simulation of tumour motion dose effects during flattened and unflattened ITV-based VMAT lung SBRT

Purpose

Restricted studies comparing different dose rate parameters are available while ITV-based VMAT lung SBRT planning leads to perform the analysis of the most suitable parameters of the external beams used. The special emphasis was placed on the impact of dose rate on dose distribution variations in target volumes due to interplay effects.

Methods

Four VMAT plans were calculated for 15 lung tumours using 6 MV photon beam quality (flattening filter FF vs. flattening filter free FFF beams) and maximum dose rate of 600 MU/min, 1000 MU/min and 1400 MU/min. Three kinds of motion simulations were performed finally giving 180 plans with perturbed dose distributions.

Results

6FFF-1400 MUs/min plans were characterized by the shortest beam on time (1.8 ± 0.2 min). Analysing the performed motion simulation results, the mean dose (Dmean) is not a sensitive parameter to related interplay effects. Looking for local maximum and local minimum doses, some discrepancies were found, but their significance was presented for individual patients, not for the whole cohort. The same was observed for other verified dose metrics.

Conclusions

Generally, the evaluation of VMAT robustness between FF and FFF concepts against interplay effect showed a negligible effect of simulated motion influence on tumour coverage among different photon beam quality parameters. Due to the lack of FFF beams, smaller radiotherapy centres are able to perform ITV-based VMAT lung SBRT treatment in a safe way. Radiotherapy department having FFF beams could perform safe, fast and efficient ITV-based VMAT lung SBRT without a concern about significance of interplay effects.

Stereotactic ablative body radiotherapy versus conventionally fractionated radiotherapy for early stage large cell neuroendocrine carcinoma of the lung

Aim

Some patients with early stage large cell neuroendocrine carcinoma (LCNEC) of the lung are not surgical candidates and will be managed with radiotherapy. We used the national cancer database to identify predictors of stereotactic radiotherapy and compare outcomes.

Materials & methods

We queried national cancer database for T1-2N0 LCNEC treated with radiation. Logistic regression and Cox regression identified predictors of stereotactic ablative body radiotherapy (SABR) and survival, respectively.

Results

We identified 754 patients, with 238 (32%) treated with SABR. Predictors of SABR were distance to facility, no chemotherapy, academic center, T1 and recent year. After propensity matching, median survival was 34.7 months compared with 23.7 months in favor of SABR (p = 0.02).

Conclusion

SABR for LCNEC has increased over time and was associated with improved survival.