Repair of Radiation Damage and Radiation Injury to the Spinal Cord. In: Jandial R, Chen MY, editors. Regenerative Biology of the Spine and Spinal Cord. New York: Springer; 2012. pp. 89-100. [DOI: 10.1007/978-1-4614-4090-1_6]

Compound 7 regulates microglia polarization and attenuates radiation-induced myelopathy via the Nrf2 signaling pathway in vivo and in vitro studies

BACKGROUND

Radiation-induced myelopathy (RM) is a significant complication of radiotherapy with its mechanisms still not fully understood and lacking effective treatments. Compound 7 (C7) is a newly identified, potent, and selective inhibitor of the Keap1-Nrf2 interaction. This study aimed to explore the protective effects and mechanisms of C7 on RM in vitro and in vivo.

METHODS

Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), reactive oxygen species (ROS) and mitochondrial polarization, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, genetic editing techniques, locomotor functions, and tissue staining were employed to explore the protective effects and underlying mechanisms of C7 in radiation-induced primary rat microglia and BV2 cells, as well as RM rat models.

RESULTS

In this study, we found that C7 inhibited the production of pro-inflammation cytokines and oxidative stress induced by irradiation in vitro. Further, the data revealed that radiation worsened the locomotor functions in rats, and C7 significantly improved histological and functional recovery in RM rats. Mechanically, C7 activated Nrf2 signaling and promoted the microglia transformation from M1 to M2 phenotype.

CONCLUSION

C7 could ameliorate RM by boosting Nrf2 signaling and promoting M2 phenotype microglia polarization in vitro and in vivo.

Orthopedic therapeutic surgery for bone metastasis of liver cancer: Clinical efficacy and prognostic factors

Objectives

In this study, the objectives were to investigate the clinical efficacy of orthopedic therapeutic surgery (OTS) in patients with bone metastasis of liver cancer and explore the prognostic factors.

Methods

The electronic medical records of patients with bone metastasis of liver cancer in the Third Affiliated Hospital of Naval Medical University from September 2016 to August 2021 were retrospectively collected. A total of 53 patients were included. Patients were assigned to the OTS (n = 35) or the control group (n = 18) based on receiving orthopedic therapeutic surgery or conservative treatment. The pre/posttreatment Karnofsky Performance Status scale (KPS) and numeric rating scale (NRS) scores were compared. Univariate and multivariate Cox regression analyses were used to explore the prognostic factors affecting survival after bone metastasis. Logistic regression analyses were adopted to discover potential factors that contributed to greater KPS score improvement.

Results

The axial bone accounted for 69.8% of all bone metastases. The proportion of multiple bone metastases was 52.8%. After surgery, the median KPS score of the OTS group increased from 60 to 80 (p < 0.001), and the median increase in the OTS group was higher than that of the control group (p = 0.033). The median NRS score of the OTS group declined from 6 to 2 after surgery (p < 0.001), and the median decline in the OTS group was higher (p = 0.001). The median survival was 10 months in the OTS group vs. 6 months in the control group (p < 0.001). Higher pretreatment KPS scores, undergoing liver primary lesion surgery, and undergoing orthopedic therapeutic surgery were protective factors of survival. Undergoing orthopedic therapeutic surgery greatly improved the KPS score.

Conclusions

Orthopedic therapeutic surgery for bone metastasis of liver cancer provides benefits to the quality of life. Patients who have their primary liver lesions removed, undergo orthopedic therapeutic surgery, and have a better physical condition before treatment tend to have longer survival.

Analysis of deep inspiration breath-hold technique to improve dosimetric and clinical advantages in postoperative intensity-modulated radiation therapy for thymomas

Background

Radiation therapy is one of the essential treatment modalities for invasive thymomas. Clinically, respiratory motion poses a challenge for the radiotherapy of thoracic tumors. One method to address this issue is to train patients to hold their breath at the end of deep inspiration. The purpose of this retrospective cohort study was to investigate the dosimetric and clinical advantages of the deep inspiration breath-hold (DIBH) technique in postoperative intensity-modulated radiation therapy (IMRT) for thymomas.

Methods

Thymoma patients undergoing postoperative IMRT were included. Each patient underwent two computed tomography (CT) scans, one under free breath (FB) and the other under DIBH. Dosimetric parameters of organs at risk (OARs) were evaluated in three series plans. Dose analysis and volume comparisons were conducted during FB-3 mm (FB with 3 mm internal target volume margin), FB-10 mm (FB with 10 mm internal target volume margin), and DIBH and compared using a paired sample Student’s t-test. Normal tissue complication probabilities (NTCP) for lungs and heart were calculated and compared.

Results

The total lung volume significantly increased by 31% (4,216±198 vs. 2,884±166 mL) and the heart volume reduced by 12% (552±25 vs. 636±35 mL) between DIBH acquisitions compared to FB. A significant improvement was observed in all the dosimetric parameters (D_mean, V20, V5) of the lung on DIBH compared to FB-3 mm (54%±2.85% vs. 47%±2.90%, P<0.001; 15%±1.37% vs. 12%±1.32%, P=0.004; and 10.28±0.58 vs. 8.76±0.57 Gy, P<0.001, respectively), as well as in the D_max and D2% of the esophagus and spine. The lung volume increment was related to a reduction in the mean dose of lungs, with a correlation coefficient of r=0.27, P=0.03. The NTCP values for pneumonitis significantly reduced with DIBH compared to the FB state (0.6% vs. 1.1%, P<0.001).

Conclusions

The radiation dose to the OARs can be significantly reduced by using the DIBH technique in postoperative IMRT for thymomas. The increased volume of lungs using DIBH acquisitions can significantly reduce the incidence of pneumonitis.

Case Report: A Novel Lateral Approach to the C7, C8, and T1 Intervertebral Foramina for Resection of Malignant Peripheral Nerve Sheath Neoplasia, Followed by Adjunctive Radiotherapy, in Three Dogs

This case report describes the diagnosis, management and outcome of three dogs with peripheral nerve sheath tumors (PNSTs) involving the brachial plexus, C7 (case 1), C8 (case 2), and C8 and T1 (case 3) spinal nerves and nerve roots with intrathoracic invasion. Surgical resection required thoracic limb amputation and removal of the first rib, facilitating a novel lateral approach to the spinal nerves and foramina in all cases. This was followed by hemilaminectomy and rhizotomy in cases 1 and 2. Adjunctive radiotherapy was then performed in all dogs. All three dogs regained a good quality of life in the short-term following surgery. Two were euthanased after 3 and 10 months, following detection of a pulmonary mass in one case and multiple thoracic and abdominal masses in the other. The third dog was alive and well at the time of writing (7 months post-surgery). This surgical approach facilitated good access and allowed gross neoplastic tissue to be resected. The ease of surgical access was dependent, to a degree, on the size of the patient. This surgical approach can be considered in cases of PNSTs involving the caudal cervical or cranial thoracic spinal nerves and nerve roots. Adjunctive radiotherapy should be considered as part of a multi-modal approach to these challenging tumors due to the difficulty of achieving clean margins, particularly proximally, even with optimal surgical access.

Radiation-induced brain structural and functional abnormalities in presymptomatic phase and outcome prediction

Radiation therapy, a major method of treatment for brain cancer, may cause severe brain injuries after many years. We used a rare and unique cohort of nasopharyngeal carcinoma patients with normal-appearing brains to study possible early irradiation injury in its presymptomatic phase before severe, irreversible necrosis happens. The aim is to detect any structural or functional imaging biomarker that is sensitive to early irradiation injury, and to understand the recovery and progression of irradiation injury that can shed light on outcome prediction for early clinical intervention. We found an acute increase in local brain activity that is followed by extensive reductions in such activity in the temporal lobe and significant loss of functional connectivity in a distributed, large-scale, high-level cognitive function-related brain network. Intriguingly, these radiosensitive functional alterations were found to be fully or partially recoverable. In contrast, progressive late disruptions to the integrity of the related far-end white matter structure began to be significant after one year. Importantly, early increased local brain functional activity was predictive of severe later temporal lobe necrosis. Based on these findings, we proposed a dynamic, multifactorial model for radiation injury and another preventive model for timely clinical intervention. Hum Brain Mapp 39:407-427, 2018. © 2017 Wiley Periodicals, Inc.

Diffusion tensor imaging study on radiation-induced brain injury in nasopharyngeal carcinoma during and after radiotherapy

AIMS AND BACKGROUND

The aim of this study was to monitor the mircostructure change of temporal lobe during the acute and subacute stage of radiation-induced brain injury using magnetic resonance diffusion tensor imaging (DTI) in nasopharyngeal carcinoma patients.

METHODS AND STUDY DESIGN

Eighty patients diagnosed with nasopharyngeal carcinoma and treated with the first radiotherapy from July 2010 to May 2012 were enrolled. Routine brain magnetic resonance imaging (MRI) and DTI were conducted in all patients before and during radiotherapy (radiation dose was 20, 40, and 60 Gy, respectively). The MRI and DTI were also performed in the 1st, 2nd, and 3rd month after radiotherapy in 47 cases of 80 patients. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of DTI during different stages were dynamically observed and analyzed.

RESULTS

The ADC values were increased and the FA values were decreased with the increase of radiation dose (20, 40, and 60 Gy) during the radiotherapy, but there was no significant difference in ADC value or FA value between before and during radiotherapy (p&gt;0.05). Compared with before radiotherapy, the ADC values were significantly increased and the FA values were significantly decreased at the 1st month, 2nd month, and 3rd month after radiotherapy (all p&lt;0.05).

CONCLUSIONS

Diffusion tensor imaging reflects the microstructure change of radiation-induced brain injury in the acute and subacute stage, which provides an objective basis for early intervention of potential irreversible brain injury in the late delayed stage, and has important significance for improving the overall efficacy of radiotherapy.