Safety of thoracic radiotherapy in patients with prior immune-related adverse events from immune checkpoint inhibitors

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.

An 18F-FDG PET/CT and Mean Lung Dose Model to Predict Early Radiation Pneumonitis in Stage III Non-Small Cell Lung Cancer Patients Treated with Chemoradiation and Immunotherapy

Radiation pneumonitis (RP) that develops early (i.e., within 3 mo) (RPEarly) after completion of concurrent chemoradiation (cCRT) leads to treatment discontinuation and poorer survival for patients with stage III non-small cell lung cancer. Since no RPEarly risk model exists, we explored whether published RP models and pretreatment 18F-FDG PET/CT-derived features predict RPEarly Methods: One hundred sixty patients with stage III non-small cell lung cancer treated with cCRT and consolidative immunotherapy were analyzed for RPEarly Three published RP models that included the mean lung dose (MLD) and patient characteristics were examined. Pretreatment 18F-FDG PET/CT normal-lung SUV featured included the following: 10th percentile of SUV (SUVP10), 90th percentile of SUV (SUVP90), SUVmax, SUVmean, minimum SUV, and SD. Associations between models/features and RPEarly were assessed using area under the receiver-operating characteristic curve (AUC), P values, and the Hosmer-Lemeshow test (pHL). The cohort was randomly split, with similar RPEarly rates, into a 70%/30% derivation/internal validation subset. Results: Twenty (13%) patients developed RPEarly Predictors for RPEarly were MLD alone (AUC, 0.72; P = 0.02; pHL, 0.87), SUVP10, SUVP90, and SUVmean (AUC, 0.70-0.74; P = 0.003-0.006; pHL, 0.67-0.70). The combined MLD and SUVP90 model generalized in the validation subset and was deemed the final RPEarly model (RPEarly risk = 1/[1+e(- x )]; x = -6.08 + [0.17 × MLD] + [1.63 × SUVP90]). The final model refitted in the 160 patients indicated improvement over the published MLD-alone model (AUC, 0.77 vs. 0.72; P = 0.0001 vs. 0.02; pHL, 0.65 vs. 0.87). Conclusion: Patients at risk for RPEarly can be detected with high certainty by combining the normal lung's MLD and pretreatment 18F-FDG PET/CT SUVP90 This refined model can be used to identify patients at an elevated risk for premature immunotherapy discontinuation due to RPEarly and could allow for interventions to improve treatment outcomes.

Opportunities and challenges in combining immunotherapy and radiotherapy in esophageal cancer

BACKGROUND

Immunotherapy has shown promise in the treatment of esophageal cancer, but using it alone only benefits a small number of patients. Most patients either do not have a significant response or develop secondary drug resistance. The combination of radiotherapy and immunotherapy appears to be a promising approach to treating esophageal cancer.

PURPOSE

We reviewed milestone clinical trials of radiotherapy combined with immunotherapy for esophageal cancer. We then discussed potential biomarkers for radiotherapy combined with immunotherapy, including programmed cell death-ligand 1 (PD-L1) status, tumor mutation burden (TMB), tumor-infiltrating lymphocytes, ct-DNA, imaging biomarkers, and clinical factors. Furthermore, we emphasize the key mechanisms of radiation therapy-induced immune stimulation and immune suppression in order to propose strategies for overcoming immune resistance in radiation therapy (RT). Lastly, we discussed the emerging role of low-dose radiotherapy (LDRT) , which has become a promising approach to overcome the limitations of high-dose radiotherapy.

CONCLUSION

Radiotherapy can be considered a triggering factor for systemic anti-tumor immune response and, with the assistance of immunotherapy, can serve as a systemic treatment option and potentially become the standard treatment for cancer patients.

Induction chemoimmunotherapy may improve outcomes of chemoradiotherapy in patients with unresectable stage III NSCLC

Background

Currently, the value of induction chemoimmunotherapy before chemoradiotherapy (CRT) in unresectable stage III non-small cell lung cancer (NSCLC) has not been explored. This study was designed to explore the efficacy and safety of induction chemoimmunotherapy in patients with unresectable stage III NSCLC.

Methods

Unresectable stage III NSCLC patients who received CRT with or without induction chemoimmunotherapy between August 2014 and December 2021 were retrospectively enrolled. Progression-free survival (PFS) and overall survival (OS) were assessed from the initiation of treatment and estimated by the Kaplan-Meier method. The potential factors affecting PFS and OS were analyzed by univariate and multivariate Cox regression models. One-to-one propensity score matching (PSM) was used to further minimize confounding.

Results

A total of 279 consecutive patients were enrolled, with 53 (19.0%) receiving induction chemoimmunotherapy followed by CRT (I-CRT group), and the remaining 226 (81.0%) receiving CRT alone (CRT group). After PSM, the median PFS was 24.8 months in the I-CRT group vs. 13.3 months in the CRT group (P=0.035). The median OS was not reached (NR) vs. 36.6 months ((P=0.142). The incidence of treatment-related adverse events (TRAEs) was similar in both groups, except that the incidence of hematological toxicity was higher in the I-CRT group (77.1% vs. 58.3%, P=0.049). Compared to induction chemotherapy, induction chemoimmunotherapy demonstrated a superior objective response rate (60.4% vs. 22.2%, P<0.001) and further prolonged PFS (median NR vs. 13.2 months, P=0.009) and OS (median NR vs. 25.9 months, P=0.106) without increasing the incidence of TRAEs in patients receiving concurrent chemoradiotherapy.

Conclusion

Induction chemoimmunotherapy is safe and may improve outcomes of CRT in patients with unresectable stage III NSCLC. Moreover, induction chemoimmunotherapy may further improve treatment response and survival outcomes compared to induction chemotherapy before cCRT.

Encephalitis in a patient with hypopharynx cancer treated with immune checkpoint inhibitors and radiotherapy: a case report and review of the literature

Hypopharyngeal cancer (HPC) has one of the most unfavorable prognoses among head and neck squamous cell carcinomas. Immunotherapy in combination with chemotherapy, the same as conventional induction chemotherapy, has emerged as a vital part of the induction therapy protocol for HPC. Meanwhile, the incidence of immune-related adverse events is increasing. In this light, we present the first reported case of immune-associated encephalitis in a patient with hypopharyngeal cancer treated with Camrelizumab (a PD-1 inhibitor). After receiving immunotherapy combined with chemotherapy as induction therapy, along with concurrent chemoradiotherapy, the patient presented with symptoms of fatigue, tremors, drowsiness, and an abnormal signal in the right temporal lobe as shown on a brain magnetic resonance imaging (MRI). Despite the minor elevation in protein and IgG index observed in the lumbar puncture, there is no evidence of abnormal autoantibodies or evidence of pathogenic infection. Following a thorough multidisciplinary consultation, the patient is suspected to be afflicted with immune-related autoimmune encephalitis. Intravenous methylprednisolone was prescribed as an empirical treatment at an initial dosage of 120 mg/day for 3 days, followed by steroid tapering. Finally, the patient experienced complete neurologic and radiographic (brain MRI) recovery. This case serves as a critical reminder that encephalitis is a potential diagnosis that should never be overlooked in patients undergoing immunotherapy who present with abnormal signs of the brain. The timely diagnosis and initiation of immunosuppressive therapy are key components of treating ICI-associated encephalitis.

Concurrent chemoradiotherapy versus radiotherapy alone after induction chemoimmunotherapy for stage III NSCLC patients who did not undergo surgery: a single institution retrospective study

BACKGROUND

With remarkable success and few side effects, induction chemoimmunotherapy has been used to improve the prognosis of patients with resectable or potentially resectable non-small cell lung cancer (NSCLC), even in stage III disease. However, for patients who are medically inoperable, unresectable or refuse surgery after induction chemoimmunotherapy, it is unclear whether patients should be treated with concurrent chemoradiotherapy (cCRT) or radiotherapy (RT) alone considering patient safety and tolerability. This study aimed to determine whether cCRT is safe and superior to RT alone after chemoimmunotherapy for stage III NSCLC.

METHODS

Patients diagnosed with stage III NSCLC who received chemoimmunotherapy followed by cCRT/RT alone without surgery at Tianjin Cancer Hospital between November 2018 to December 2021 were retrospectively collected. Patients were divided into two groups: induction chemoimmunotherapy followed by cCRT (cCRT cohort) or RT alone (RT alone cohort). Kaplan-Meier method was used to estimate survival. Univariate and multivariate Cox regression models were adopted to estimate risk factors for PFS.

RESULTS

Sixty-five patients were included, with 44 (67.7%) received RT alone and 21 (32.3%) received cCRT. Patients in the cCRT group had significantly prolonged PFS (HR = 0.155, p = 0.004), LPFS (HR = 0.225, p = 0.029) and DMFS (HR = 0.028, p = 0.006) than those in the RT alone group. Albeit nonsignificant, a trend toward improved OS (HR = 0.030, p = 0.069) was also observed in the cCRT group. The multivariate analysis further confirmed that cCRT (HR = 0.141, p = 0.008) was the independent factor for promoting a favorable PFS. Treatment-related adverse events were similar between groups (p > 0.05). Patients with consolidation immunotherapy exhibited a trend of improved PFS (HR = 0.398, p = 0.274) and numerically better OS (HR = 0.018, p = 0.209) compared with those without.

CONCLUSIONS

For patients with unresectable stage III NSCLC, cCRT following chemoimmunotherapy appears to be safe and may prolong survival compared with radiotherapy alone. Further investigations on the combination of chemoimmunotherapy and CRT are warranted.

Radiotherapy combined with immune checkpoint inhibitors in locally advanced/metastatic esophageal squamous cell carcinoma: clinical trials, efficacy and future directions

Esophageal squamous cell carcinoma (ESCC) is a common malignancy worldwide and often diagnosed at advanced stages with poor prognosis. Combination of radiotherapy and immunotherapy seems to be a promising approach for treating ESCC. This comprehensive review article summarizes the current state of combination of radiotherapy and immunotherapy in locally advanced/metastatic ESCC, delineates the clinical trials that merit attention, and outlines unresolved issues and future research directions in this field. The clinical trial findings suggest that radio-immunotherapy combination may improve tumor response and overall survival with manageable side effects, highlighting the importance of patient selection and the necessity for further research to optimize treatment strategies. Issues such as irradiation dosage, fractionation regimen, irradiation site and technique of radiotherapy, as well as the timing, sequence and duration of combination therapy will all affect treatment outcomes, justifying further in-depth investigation.

Radiation combined with immune checkpoint inhibitors for unresectable locally advanced non-small cell lung cancer: synergistic mechanisms, current state, challenges, and orientations

Until the advent of immune checkpoint inhibitors (ICIs), definitive radiotherapy (RT) concurrently with chemotherapy was recommended for unresectable, locally advanced non-small cell lung cancer (LA-NSCLC). The trimodality paradigm with consolidation ICIs following definitive concurrent chemoradiotherapy has been the standard of care since the PACIFIC trial. Preclinical evidence has demonstrated the role of RT in the cancer-immune cycle and the synergistic effect of RT combined with ICIs (iRT). However, RT exerts a double-edged effect on immunity and the combination strategy still could be optimized in many areas. In the context of LA-NSCLC, optimized RT modality, choice, timing, and duration of ICIs, care for oncogenic addicted tumors, patient selection, and novel combination strategies require further investigation. Targeting these blind spots, novel approaches are being investigated to cross the borders of PACIFIC. We discussed the development history of iRT and summarized the updated rationale for the synergistic effect. We then summarized the available research data on the efficacy and toxicity of iRT in LA-NSCLC for cross-trial comparisons to eliminate barriers. Progression during and after ICIs consolidation therapy has been regarded as a distinct resistance scenario from primary or secondary resistance to ICIs, the subsequent management of which has also been discussed. Finally, based on unmet needs, we probed into the challenges, strategies, and auspicious orientations to optimize iRT in LA-NSCLC. In this review, we focus on the underlying mechanisms and recent advances of iRT with an emphasis on future challenges and directions that warrant further investigation. Taken together, iRT is a proven and potential strategy in LA-NSCLC, with multiple promising approaches to further improve the efficacy. Video Abstract.

Palliative extracranial radiotherapy in patients receiving immunotherapy for non-small cell lung cancer: a narrative review

Background and Objective

Role of radiotherapy (RT) in the era of immuno-oncology (IO) in advanced non-small cell lung cancer (NSCLC) is rapidly changing. RT is not only intended for addressing palliation symptoms but also is considered as a potential tool potentializing an immunogenic effect of given drugs. However, the best timing, techniques, doses, volumes, and its use for asymptomatic patients is a subject of research. We performed a review on the role of palliative RT schedules in combination with IO for advanced NSCLC. Indications in symptomatic and asymptomatic patients, outcomes, toxicity, and possible developments are discussed.

Methods

A literature search was conducted in MEDLINE and PubMed databases and clinicaltrials.gov using the keywords 'lung cancer' AND "immunotherapy" AND 'radiotherapy' OR "palliative radiotherapy".

Key Content and Findings

Body of evidence indicate that palliative RT used in combination with IO is effective in terms of symptom management and safe; does not increase the risk of serious side effects, including serious pulmonary toxicity. We have limited data evidencing improvement of survival by addition of short ablative RT dose to one site of the disease to IO in oligometastatic NSCLC. Some data indicate that short ablative doses of stereotactic body radiation therapy (SBRT) are more effective with regard to treatment response and survival than protracted RT schedule with lower fractional doses. However, this may be a selection bias of better prognostic patients who underwent SBRT. The use of steroids being a potential concern during IO should not be prohibited if clinically indicated during palliative RT. Its detrimental effect shown in some studies may also be a result of selection bias, because steroids given for not cancer-related causes during IO did not decrease survival.

Conclusions

RT for symptom management may be used during, directly before or after IO. This has a potential to ease symptom burdens and improve performance status (PS). However, still more studies are needed to establish optimal guidelines in asymptomatic patients for appropriate timing, volumes, dose, and fractionation schedules of palliative RT use in combination with IO.

Interstitial pneumonitis associated with combined regimen of immunotherapy and conventional therapies-pharmacovigilance database analysis with real-world data validation

BACKGROUND

Immune checkpoint inhibitor (ICI) therapy combined with conventional therapies is being broadly applied in non-small cell lung cancer (NSCLC) patients. However, the risk of interstitial pneumonitis (IP) following a combined regimen is incompletely characterized.

METHODS

A total of 46,127 NSCLC patients were extracted for disproportionality analyses of IP from the Food and Drug Administration's Adverse Event Reporting System (FAERS) database. A total of 1108 NSCLC patients who received ICI treatment at Nanfang Hospital of Southern Medical University were collected and utilized for real-world validation.

RESULTS

Of the 46,127 patients with NSCLC, 3830 cases (8.3%; 95% confidence interval [CI], 8.05-8.56) developed IP. Multivariable logistic regression analyses revealed that the adjusted ROR of ICI combined with radiation (RT) was the highest (121.69; 95% CI, 83.60-184.96; P < 0.0001) among all therapies, while that of ICI combined with chemotherapy (CHEMO) or targeted therapy (TARGET) was 0.90 (95% CI, 0.78-1.04; P = 0.160) and 1.49 (95% CI, 0.95-2.23; P = 0.065), respectively, using ICI monotherapy as reference. Furthermore, analyses from our validation cohort of 1108 cases showed that the adjusted odds ratio of ICI combined with RT was the highest (12.25; 95% CI, 3.34-50.22; P < 0.01) among all the therapies, while that of ICI combined with CHEMO or TARGET was 2.32 (95% CI, 0.89-7.92; P = 0.12) and 0.66 (95% CI, 0.03-4.55; P = 0.71), respectively, using ICI monotherapy as reference.

CONCLUSIONS

Compared with ICI monotherapy, ICI combined with RT, rather than with CHEMO or TARGET, is associated with a higher risk of IP in NSCLC patients. Hence, patients receiving these treatments should be carefully monitored for IP.

Immune-related arthritis following pelvic radiation therapy in a patient with lung cancer receiving long-term immune checkpoint blocker treatment: Case report

Radiotherapy can trigger immune-related out-of-field “abscopal” response. We report a patient with advanced NSCLC (non-small cell lung cancer) receiving long-term anti-PD1 (programmed cell death protein 1) who have developed out-of-field immune-related arthritis following pelvic irradiation.

Research Progress on Radiotherapy Combined with Immunotherapy for Associated Pneumonitis During Treatment of Non-Small Cell Lung Cancer

Radiation pneumonitis is a common and serious complication of radiotherapy for thoracic tumours. Although radiotherapy technology is constantly improving, the incidence of radiation pneumonitis is still not low, and severe cases can be life-threatening. Once radiation pneumonitis develops into radiation fibrosis (RF), it will have irreversible consequences, so it is particularly important to prevent the occurrence and development of radiation pneumonitis. Immune checkpoint inhibitors (ICIs) have rapidly altered the treatment landscape for multiple tumour types, providing unprecedented survival in some patients, especially for the treatment of non-small cell lung cancer (NSCLC). However, in addition to its remarkable curative effect, ICls may cause immune-related adverse events. The incidence of checkpoint inhibitor pneumonitis (CIP) is 3% to 5%, and its mortality rate is 10% to 17%. In addition, the incidence of CIP in NSCLC is higher than in other tumour types, reaching 7%–13%. With the increasing use of immune checkpoint inhibitors (ICls) and thoracic radiotherapy in the treatment of patients with NSCLC, ICIs may induce delayed radiation pneumonitis in patients previously treated with radiation therapy, or radiation activation of the systemic immune system increases the toxicity of adverse reactions, which may lead to increased pulmonary toxicity and the incidence of pneumonitis. In this paper, the data about the occurrence of radiation pneumonitis, immune pneumonitis, and combined treatment and the latest related research results will be reviewed.

Immune checkpoint inhibitor-related pneumonitis in non-small cell lung cancer: A review

Immune checkpoint inhibitors (ICIs) have shown definite therapeutic effects in various types of cancers, especially non-small cell lung cancer (NSCLC). However, ICIs have unique side effects, called immune-related adverse events (irAEs), which can occur in various systems throughout the body. Among such irAEs, immune checkpoint inhibitor-related pneumonitis (ICI-P) is a fatal adverse reaction. In this review, we discussed the risk factors, pathogenesis, clinical characteristics, radiological manifestations, pathological features, diagnosis, grading, and management of ICI-P in NSCLC and the relationship between ICI-P and the efficacy of ICI therapy. In addition, we discussed the predictive factors for ICI-P. This review will play a crucial role in the prediction, evaluation, and management of ICI-P for widespread application of immunotherapy.

Comprehensive Pneumonitis Profile of Thoracic Radiotherapy Followed by Immune Checkpoint Inhibitor and Risk Factors for Radiation Recall Pneumonitis in Lung Cancer

Purpose

Whilst survival benefits of thoracic radiotherapy (TRT) followed by immune checkpoint inhibitor (ICI) have been reported in patients with lung cancer, the potential high risk of treatment-related pneumonitis remains a concern. Asians may be more sensitive to lung toxicity than other races. This retrospective study intended to provide a comprehensive pneumonitis profile of TRT followed by ICI and investigate the risk factors from a Chinese cohort of lung cancer.

Methods and Materials

From January 2016 to July 2021, 196 patients with lung cancer who received TRT prior to ICI were retrospectively analyzed. Treatment-related pneumonitis, including checkpoint inhibitor pneumonitis (CIP), radiation pneumonitis (RP), and radiation recall pneumonitis (RRP), were recorded and graded through medical records and chest computed tomography. Characteristics predictive of pneumonitis were assessed using logistic regression models, and the receiver operating characteristic analyses were performed to identify optimal cut points for quantitative variables.

Results

With a median follow-up of 18 months, a total of 108 patients (55.1%) developed treatment-related pneumonitis during ICI therapy, with an incidence of 25.5% for grade 2 or higher (G2+) and 4.1% for G3+. The overall rates of CIP, RP and RRP were 8.2% (n=16), 46.9% (n=92) and 7.1% (n=14), respectively. With a total mortality rate of 1.5%, vast majority of the patients recovered from pneumonitis or remained stable. No patients died of RRP. Half of the patients with G2+ RP who withheld ICI therapy restarted ICI safely after resolution of RP. The history of chronic pulmonary diseases (P=0.05), mean lung dose (MLD, P=0.038), percent volume of lung receiving ≥5 Gy (V5, P=0.012) and percent volume of lung receiving ≥20 Gy (V20, P=0.030) predicted the occurrence of RRP in univariate analyses. Interval between TRT and ICI less than 3 months was an independent predictor for G2+ treatment-related pneumonitis in a multivariate model (Odds ratio OR=2.787, P=0.004).

Conclusions

Treatment-related pneumonitis, especially RRP, is acceptable and manageable in the setting of TRT followed by ICI in this Asian population. Dosimetric parameters MLD, V5 and V20 may improve the predictions of RRP in clinical practice.

Pneumonitis after Stereotactic Thoracic Radioimmunotherapy with Checkpoint Inhibitors: Exploration of the Dose-Volume-Effect Correlation

Simple Summary

Stereotactic body radiation therapy (SBRT) is widely applied for treatment of early stage lung cancer and pulmonary metastases. Modern immune checkpoint blockade (ICB) is progressively used in cancer treatment. Pneumonitis is a relevant side effect of both thoracic SBRT and ICB. Currently, it remains unclear whether we can presume the same radiation dose–volume–effect correlations and dose constraints for safe application of SBRT + ICB. We present a dose–volume–effect correlation analysis method using pneumonitis contours and dose–volume histograms (DVH). We showed dosimetric differences for pneumonitis volumes between SBRT + ICB and SBRT alone. We found a large extent of pneumonitis, even bilateral and apart from the radiation field for combined SBRT + ICB. We noticed a shift in pneumonitis DVHs towards lower doses and a trend towards decreased areas under the curve (AUC) for SBRT + ICB. This provides a direction for re-evaluation and potential adaptation of lung dose constraints for combined SBRT and ICB.

Abstract

Thoracic stereotactic body radiation therapy (SBRT) is extensively used in combination with immune checkpoint blockade (ICB). While current evidence suggests that the occurrence of pneumonitis as a side effect of both treatments is not enhanced for the combination, the dose–volume correlation remains unclear. We investigate dose–volume–effect correlations for pneumonitis after combined SBRT + ICB. We analyzed patient clinical characteristics and dosimetric data for 42 data sets for thoracic SBRT with ICB treatment (13) and without (29). Dose volumes were converted into 2 Gy equivalent doses (EQD2), allowing for dosimetric comparison of different fractionation regimes. Pneumonitis volumes were delineated and corresponding DVHs were analyzed. We noticed a shift towards lower doses for combined SBRT + ICB treatment, supported by a trend of smaller areas under the curve (AUC) for SBRT+ ICB (median AUC 1337.37 vs. 5799.10, p = 0.317). We present a DVH-based dose–volume–effect correlation method and observed large pneumonitis volumes, even with bilateral extent in the SBRT + ICB group. We conclude that further studies using this method with enhanced statistical power are needed to clarify whether adjustments of the radiation dose constraints are required to better estimate risks of pneumonitis after the combination of SBRT and ICB.

Complications following novel therapies for non-small cell lung cancer

The emergence of tyrosine kinase inhibitors and immune checkpoint inhibitors has paved a new era for the management of non-small cell lung cancer, which has for many years lacked major clinical breakthroughs. Historically, 5-year overall survival remained below 5% in individuals with metastatic disease. These novel treatments have led to significant prolongation of survival in the locally advanced and metastatic setting, exceeding 25% in selected populations. However, they present new challenges to clinicians due to their inherently different spectrum of toxicity unique to each specific drug's pharmacodynamic profile. Internists commonly come across these side effects in their daily clinical practice. Their optimal recognition and management are of utmost importance, because it is associated with significant improvements in patient survival outcomes and their quality of life. The aim of this review is to summarize the complications following these novel treatments for non-small cell lung cancer.

Irradiation immunity interactions

The immune system can influence cancer development by both impeding and/or facilitating tumour growth and spread. A better understanding of this complex relationship is fundamental to optimise current and future cancer therapeutic strategies. Although typically regarded as a localised and immunosuppressive anti‐cancer treatment modality, radiation therapy has been associated with generating profound systemic effects beyond the intended target volume. These systemic effects are immune‐driven suggesting radiation therapy can enhance anti‐tumour immunosurveillance in some instances. In this review, we summarise how radiation therapy can positively and negatively affect local and systemic anti‐tumour immune responses, how co‐administration of immunotherapy with radiation therapy may help promote anti‐tumour immunity, and how the use of immune biomarkers may help steer radiation therapy‐immunotherapy personalisation to optimise clinical outcomes.

LITE SABR M1: A phase I trial of Lattice stereotactic body radiotherapy for large tumors

PURPOSE

Stereotactic body radiotherapy (SBRT) is an attractive treatment option for patients with metastatic and/or unresectable tumors, however its use is limited to smaller tumors. Lattice is a form of spatially fractionated radiotherapy that may allow safe delivery of ablative doses to bulky tumors. We previously described Lattice SBRT, which delivers 20 Gy in 5 fractions with a simultaneous integrated boost to 66.7 Gy in a defined geometric arrangement (Lattice boost). The goal of this study was to prospectively evaluate the acute toxicity and quality of life (QoL) of patients with large tumors (>5 cm) treated with Lattice SBRT.

METHODS

This was a single-arm phase I trial conducted between October 2019 and August 2020. Patients with tumors > 4.5 cm were eligible. Lattice SBRT was delivered every other day. The primary outcome was the rate of 90-day treatment-associated (probably or definitely attributable) grade 3 + acute toxicity by Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 criteria. Other outcomes included changes in patient reported toxicity and QoL inventories, GTV, and peripheral blood cytokines.

RESULTS

Twenty patients (22 tumors) were enrolled. Median GTV was 579.2 cc (range: 54.2-3713.5 cc) in volume and 11.1 cm (range: 5.6-21.4 cm) in greatest axial diameter. Fifty percent of tumors were in the thorax, 45% abdomen/pelvis, and 5% extremity. There was no likely treatment-associated grade 3 + toxicity in the 90-day period (acute and sub-acute). There was one case of grade 4 toxicity possibly associated with Lattice SBRT.

CONCLUSIONS

This phase I study met its primary endpoint of physician reported short-term safety. An ongoing phase II clinical trial of Lattice SBRT will evaluate late safety and efficacy of this novel technique.

Bilateral Regional Nodal Irradiation using Volumetric Modulated Arc Therapy (VMAT): Dosimetric analysis and feasibility

PURPOSE/OBJECTIVES

Dosimetric and technical challenges often limit radiotherapy (RT) target coverage for breast cancer patients who require bilateral breast/chest wall and regional nodal irradiation (RNI). We evaluated the feasibility of using volumetric modulated arc therapy (VMAT) to administer bilateral comprehensive RNI including the internal mammary nodes.

MATERIALS/METHODS

We analyzed all patients treated at our institution with bilateral RNI using VMAT from 2017-2020. Medical records were reviewed to ascertain clinicopathologic features, radiotherapeutic parameters and treatment-related adverse events.

RESULTS

The cohort comprised 12 patients who underwent VMAT for bilateral RNI, with a median follow-up of 14.5 months. Median V5Gy for bilateral lungs was 96.1% (range: 84.5%-99.8%). Median V20Gy for each lung was 27.5% (range: 14.9-38.1%). Cardiac mean dose was a median of 699 cGy (range: 527-1117 cGy). Five patients (41%) developed grade 1 cough/dyspnea, with one patient developing grade 3 dyspnea. Of note, three of these (60%) were current or former smokers. No patient received glucocorticoid therapy or required respiratory intervention and none developed longer term pulmonary complaints. Decline in ejection fraction occurred in one patient with a pre-existing cardiac condition who also received anthracycline-based chemotherapy and trastuzumab. Only one patient experienced locoregional recurrence with synchronous distant progression and subsequently succumbed to her disease. No secondary cancers have been noted to date.

CONCLUSION

VMAT appears to be a feasible and tolerable RT modality for breast cancer patients who require bilateral comprehensive adjuvant RT with RNI obtaining excellent target coverage. No patients required medical intervention for pulmonary complaints despite a median bilateral V5 approaching 100%, providing further evidence that V5 is not predictive for complications.

Biological Bases of Immune-Related Adverse Events and Potential Crosslinks With Immunogenic Effects of Radiation

Immune checkpoint inhibitors have gained an established role in the treatment of different tumors. Indeed, their use has dramatically changed the landscape of cancer care, especially for tumor types traditionally known to have poor outcomes. However, stimulating anticancer immune responses may also elicit an unusual pattern of immune-related adverse events (irAEs), different from those of conventional chemotherapy, likely due to a self-tolerance impairment featuring the production of autoreactive lymphocytes and autoantibodies, or a non-specific autoinflammatory reaction. Ionizing radiation has proven to promote both positive pro-inflammatory and immunostimolatory activities, and negative anti-inflammatory and immunosuppressive mechanisms, as a result of cross-linked interactions among radiation dose, the tumor microenvironment and the host genetic predisposition. Several publications argue in favor of combining immunotherapy and a broad range of radiation schedules, based on the recent evidence of superior treatment responses and patient survival. The synergistic modulation of the immune response by radiation therapy and immunotherapeutics, particularly those manipulating T-cell activation, may also affect the type and severity of irAEs, suggesting a relationship between the positive antitumor and adverse autoimmune effects of these agents. As yet, information on factors that may help to predict immune toxicity is still lacking. The aim of our work is to provide an overview of the biological mechanisms underlying irAEs and possible crosslinks with radiation-induced anticancer immune responses. We believe such an overview may support the optimization of immunotherapy and radiotherapy as essential components of multimodal anticancer therapeutic approaches. Challenges in translating these to clinical practice are discussed.

Safety of thoracic radiotherapy after PD-(L)1 inhibitor treatment in patients with lung cancer

Background

The safety of thoracic radiotherapy (TRT) after programmed death 1/programmed death ligand 1 (PD‐(L)1) inhibitor treatment in patients with lung cancer was scarcely reported. This retrospective study was conducted to evaluate the incidence, severity, and risk factors of symptomatic treatment‐related pneumonitis in patients with lung cancer who received this sequential combination.

Methods

We conducted a retrospective study of a cohort of patients with lung cancer who received TRT after at least two cycles of PD‐(L)1 inhibitor treatment between January 2018 and August 2020. Treatment‐related pneumonitis was evaluated and analyzed to illustrate the safety profile of this sequential combination. Potential risk factors were explored by univariate and multivariate logistic regression analyses.

Results

Among the 828 patients with prior PD‐(L)1 inhibitor treatment, 96 patients receiving subsequent TRT were included in the analysis. Of these, 49 patients (51%) received radical TRT while 47 patients (49%) received palliative TRT. The median total dose was 52 Gy (IQR 50–60 Gy). The median time from the initiation of PD‐(L)1 inhibitor treatment to TRT was 4.8 months (1.6–14.1 months) with most of the patients (74%) administering no less than four cycles of PD‐(L)1 inhibitor. During follow‐up, 47 patients (48.96%) developed symptomatic treatment‐related pneumonitis (grade 2 n = 28, grade ≥3 n = 19) while six patients (6.25%) suffered from fatal toxicity. The median time of pneumonitis onset after completion of TRT was 35 days (0–177 days) with six patients developing during TRT. Pulmonary emphysema and lung V20 were demonstrated to be independent risk factors of symptomatic pneumonitis (OR: 5.67, 95% CI: 1.66–19.37, p = 0.006; OR: 3.49, 95% CI: 1.41–8.66, p = 0.007, respectively).

Conclusion

TRT after PD‐(L)1 inhibitor treatment resulted in significantly increased incidence and severity of treatment‐related pneumonitis in patients with lung cancer. Intensive attention should be emphasized to the safety of this sequential combination in clinical practice.

Late Central Airway Toxicity after High-Dose Radiotherapy: Clinical Outcomes and a Proposed Bronchoscopic Classification

Simple Summary

High-dose radiotherapy is frequently used to treat lung cancer, however, it can cause serious central airway toxicity. Although radiation toxicity of the lung parenchyma has been studied extensively, relatively little has been published on bronchoscopic findings in the central airways and no standard classification/reporting system exists. With the growing use of high-dose (chemo)radiotherapy and high-dose hypo-fractionated radiotherapy in close proximity to central airways, as well as potential interactions with new systemic therapies, the risks and incidence of central airway toxicity may increase. In this retrospective study, we analyzed patient characteristics and clinical outcomes of 70 patients with central airway toxicity after high-dose radiotherapy. Furthermore, we analyzed the post-radiotherapy bronchoscopic images to identify main patterns of airway toxicity. We identified luminal stenosis and vascular changes as the two main patterns and have proposed a classification system. Preliminary analysis suggests that the pattern and severity of radiation toxicity may be of prognostic value.

Abstract

The study’s purpose was to identify the bronchoscopic patterns of central airway toxicity following high-dose radiotherapy or chemoradiotherapy, and to look at the consequences of these findings. Our institutional bronchoscopy database was accessed to identify main patterns of airway toxicity observed in a seven-year period. A total of 70 patients were identified with central airway toxicity, and the findings of bronchoscopy were used to derive a classification system. Patient characteristics, time from radiotherapy to toxicity, follow-up and survival were retrospectively analyzed. Results: The main bronchoscopic patterns of airway toxicity were vascular changes (telangiectasia, loss of vascularity, necrosis) and stenosis of the lumen (moderate, severe). Indications for bronchoscopy were airway symptoms (n = 28), assessment post-CRT/surgery (n = 12), (suspected) recurrence (n = 21) or assessment of radiological findings (n = 9). Stenosis was revealed by bronchoscopy at a median time of 10.0 months (IQR: 4–23.5) after radiotherapy and subsequent follow-up after identification was 23 months (IQR: 1.5–55). The corresponding findings for vascular changes were 29 months (IQR: 10.5–48.5), and follow-up after identification was nine months (IQR: 2.5–19.5). There was a statistically significant difference in survival rates between patients with necrosis and telangiectasia (p = 0.002) and loss of vascularity (p = 0.001). Eight out of 10 deceased patients with telangiectasia died of other causes and 4/8 patients with necrosis died of other causes. We identified two main patterns of central airway toxicity visualized with bronchoscopy after high-dose radiotherapy or chemoradiotherapy, and propose a bronchoscopic classification system based on these findings. Preliminary analysis suggests that the pattern and severity of radiation damage might be of prognostic value. Prospective data are required to confirm our findings.