Risk of radiation-induced pneumonitis after helical and static-port tomotherapy in lung cancer patients and experimental rats

Dark Side of Cancer Therapy: Cancer Treatment-Induced Cardiopulmonary Inflammation, Fibrosis, and Immune Modulation

Advancements in cancer therapy increased the cancer free survival rates and reduced the malignant related deaths. Therapeutic options for patients with thoracic cancers include surgical intervention and the application of chemotherapy with ionizing radiation. Despite these advances, cancer therapy-related cardiopulmonary dysfunction (CTRCPD) is one of the most undesirable side effects of cancer therapy and leads to limitations to cancer treatment. Chemoradiation therapy or immunotherapy promote acute and chronic cardiopulmonary damage by inducing reactive oxygen species, DNA damage, inflammation, fibrosis, deregulation of cellular immunity, cardiopulmonary failure, and non-malignant related deaths among cancer-free patients who received cancer therapy. CTRCPD is a complex entity with multiple factors involved in this pathogenesis. Although the mechanisms of cancer therapy-induced toxicities are multifactorial, damage to the cardiac and pulmonary tissue as well as subsequent fibrosis and organ failure seem to be the underlying events. The available biomarkers and treatment options are not sufficient and efficient to detect cancer therapy-induced early asymptomatic cell fate cardiopulmonary toxicity. Therefore, application of cutting-edge multi-omics technology, such us whole-exome sequencing, DNA methylation, whole-genome sequencing, metabolomics, protein mass spectrometry and single cell transcriptomics, and 10 X spatial genomics, are warranted to identify early and late toxicity, inflammation-induced carcinogenesis response biomarkers, and cancer relapse response biomarkers. In this review, we summarize the current state of knowledge on cancer therapy-induced cardiopulmonary complications and our current understanding of the pathological and molecular consequences of cancer therapy-induced cardiopulmonary fibrosis, inflammation, immune suppression, and tumor recurrence, and possible treatment options for cancer therapy-induced cardiopulmonary toxicity.

Markers Useful in Monitoring Radiation-Induced Lung Injury in Lung Cancer Patients: A Review

In 2018, lung cancer was the most common cancer and the most common cause of cancer death, accounting for a 1.76 million deaths. Radiotherapy (RT) is a widely used and effective non-surgical cancer treatment that induces remission in, and even cures, patients with lung cancer. However, RT faces some restrictions linked to the radioresistance and treatment toxicity, manifesting in radiation-induced lung injury (RILI). About 30–40% of lung cancer patients will develop RILI, which next to the local recurrence and distant metastasis is a substantial challenge to the successful management of lung cancer treatment. These data indicate an urgent need of looking for novel, precise biomarkers of individual response and risk of side effects in the course of RT. The aim of this review was to summarize both preclinical and clinical approaches in RILI monitoring that could be brought into clinical practice. Next to transforming growth factor-β1 (TGFβ1) that was reported as one of the most important growth factors expressed in the tissues after ionizing radiation (IR), there is a group of novel, potential biomarkers—microRNAs—that may be used as predictive biomarkers in therapy response and disease prognosis.

Cytokines and radiation-induced pulmonary injuries

Radiation therapy is one of the most common treatment strategies for thorax malignancies. One of the considerable limitations of this therapy is its toxicity to normal tissue. The lung is the major dose-limiting organ for radiotherapy. That is because ionizing radiation produces reactive oxygen species that induce lesions, and not only is tumor tissue damaged, but overwhelming inflammatory lung damage can occur in the alveolar epithelium and capillary endothelium. This damage may result in radiation-induced pneumonitis and/or fibrosis. While describing the lung response to irradiation generally, the main focus of this review is on cytokines and their roles and functions within the individual stages. We discuss the relationship between radiation and cytokines and their direct and indirect effects on the formation and development of radiation injuries. Although this topic has been intensively studied and discussed for years, we still do not completely understand the roles of cytokines. Experimental data on cytokine involvement are fragmented across a large number of experimental studies; hence, the need for this review of the current knowledge. Cytokines are considered not only as molecular factors involved in the signaling network in pathological processes, but also for their diagnostic potential. A concentrated effort has been made to identify the significant immune system proteins showing positive correlation between serum levels and tissue damages. Elucidating the correlations between the extent and nature of radiation-induced pulmonary injuries and the levels of one or more key cytokines that initiate and control those damages may improve the efficacy of radiotherapy in cancer treatment and ultimately the well-being of patients.

Naringenin Ameliorates Radiation-Induced Lung Injury by Lowering IL-1β Level

Radiation-induced lung injury (RILI) is the main complication of radiotherapy for thoracic malignancies. Since naringenin, a potent immune-modulator, has been found to relieve bleomycin-induced lung fibrosis by restoring the balance of disordered cytokines, we sought to determine whether naringenin would mitigate RILI and to investigate the underlying mechanism. Animals received fractionated irradiation in the thoracic area to induce RILI. Enzyme-linked immunosorbent assay and MILLIPLEX assays were used for serum and bronchoalveolar lavage fluid for cytokine analyses, hematoxylin and eosin staining for pathologic changes, and Masson trichrome staining for determination of lung fibrosis. Interleukin (IL)-1β was found significantly elevated after thoracic irradiation and it triggered production of profibrotic tumor growth factor β both in vivo and in vitro, suggesting the vital role of in IL-1β in the development of RILI. Furthermore, we found that naringenin was able to ameliorate RILI through downregulation of IL-1β and restoration of the homeostasis of inflammatory factors. Our results demonstrated that naringenin could serve as a potent immune-modulator to ameliorate RILI. More importantly, we suggest that a new complementary strategy of maintaining the homeostasis of inflammatory factors combined with radiation could improve the efficacy of thoracic radiotherapy.

Treatment outcome for locally advanced non-small-cell lung cancer using TomoDirect plan and its characteristics compared to the TomoHelical plan

Introduction

TomoDirect (TD) is an intensity‐modulated radiotherapy system that uses a fixed gantry angle instead of the rotational beam delivery used in the TomoHelical (TH) system. This study was performed (1) to evaluate the treatment outcome of the TD plan for locally advanced non‐small‐cell lung cancer (NSCLC) and (2) to compare the characteristics of TD plans with those of TH plans.

Methods

Twenty‐one patients with NSCLC were treated using the TD system. The prescribed dose was 40 Gy/20 Fx for the initial planning target volume (PTV), which included the gross tumour volume (GTV) and lymph node regions. A boost plan of 20 Gy/10 Fx was then applied, focusing on the GTV. For the planning study, matched TH plans of 40 Gy for the initial PTV were created for each patient, to meet the same dosimetric constraints specified in the TD plans.

Results

The 2‐year overall survival, progression‐free survival and local control rates were 47%, 45% and 74% respectively. Grade 2 treatment‐related pneumonitis occurred in three (14%) patients. The planning study comparing TD and TH showed that dose distribution to GTV and PTV were not significantly different. The lung V5 Gy was lower in the TD plans than TH plans (46.4 ± 5.4 vs. 52.3 ± 8.5), while the V20 Gy was higher (26.2 ± 4 vs. 24 ± 4.3). The TD plans had a significantly shorter treatment time than TH plans (4.5 ± 1.3 min vs. 9.8 ± 1.5 min).

Conclusions

TD is a clinically acceptable treatment option for NSCSL. The quality of the TD and TH plans are comparable.