ABSTRACT
As early as the 20 th century, it has been observed that radiotherapy (RT), as a local therapy, can activate the adaptive immune system, resulting in spontaneous regression of tumors out of the radiation field, which is known as "abscopal effect". Although the occurrence of abscopal effect is still rare, with the gradual increase in the application of immunotherapy, more and more clinical cases of abscopal effect have been reported. Increasing attention has been paid to the therapeutic potential of RT in inducing systemic anti-tumor response. Especially, the combination of RT and immunotherapy enhances the research value of abscopal effect. However, its mechanism has not been fully elucidated, and the optimal timing, dose and fractionation of RT are also under study. How to classify the beneficiary groups is also a key issue. In this article, the history of abscopal effect, and the role of RT and immunotherapy in this phenomenon were briefly introduced, and the existing controversies in clinical application were illustrated, aiming to clarify the direction of current research and development and open a new chapter for tumor treatment in a short period of time.
ABSTRACT
Objective:To evaluate the application value of SPECT lung perfusion imaging in guiding radiotherapy path, optimizing the radiotherapy plan for lung cancer and protecting lung function during radiotherapy for locally advanced non-small cell lung cancer.Methods:In this study, 84 patients with stage Ⅲ non-resectable non-small cell lung cancer were randomly divided into the control group ( n=44) and observation group ( n=40). In the control group, radiotherapy plan based on conventional CT images was delivered, and two plans based on the lung function information suggested by conventional CT and SPECT lung perfusion imaging: P1 and P2 were given in the observation group. All patients in the observation group were finally treated according to the P2 plan. The incidence of radiation pneumonitis, and changes in lung function before and after radiotherapy were statistically compared between two groups. The dose-volume parameters of P1 and P2 were statistically compared. Results:After the plan was optimized, the incidence of radiation pneumonitis in the observation group was significantly reduced and the decline of lung function was significantly improved (both P≤0.001). The functional dose parameters were significantly improved in the P2 plans (both P<0.05), whereas the irradiation dose of organs at risk did not significantly change ( P>0.05). Conclusion:SPECT lung perfusion imaging optimizes the intensity-modulated radiotherapy plan, which can reduce the functional lung dose and increase the tumor radiotherapy dose without increasing the irradiation dose of other organs at risk.
ABSTRACT
Functional imaging plays an important role in lung cancer radiotherapy.Functional imaging techniques include single photon emission computed tomography,positron emission tomography,magnetic resonance imaging,and computed tomography.Using lung function information provided by these techniques for lung cancer radiotherapy can better protect the normal function of lung tissue,optimize the radiotherapy program,and reduce the incidence of radiation pneumonitis.With the development of perfusion and imaging technology,functional imaging technology is expected to be widely used in the precise radiotherapy of lung cancer in the future.
ABSTRACT
Objective To observe the effect of endostatin(Endostar) combined with radiotheraphy on the growth,microvessel density (MVD),the expressions of regulators of G-protein signaling 5 (RGSS),vascular endothelial growth factor (VEGF) and hypoxia-induced factor-1 α (HIF-1 α) ingastric transplantation tumor,and to explore underlying mechanism.Methods Thirty-two tumor-bearing mice were randomly divided into four groups including control group,ES group,RT group and ES + RT group.Then the tumor-bearing mice survival and tumor volume alterations were observed.After treatments of drug and RT,the inhibition rate of tumor growth and tumor MVD were measured.Immunohistochemical staining method was used to detect the expressions of RGS5,VEGF and HIF-1α.Results Compared with the ES group and control group,the ES + RT and RT treatment had effective anti-tumor effect(t=7.4,5.6,P ＜ 0.05),where as the ES + RT was more obvious in anti-tumor with the lowest value of MVD in tumor.Compared with the control group,the expression of HIF-1α in ES group,RT group,and especially ES + RT group was significantly reduced (t =6.5,8.2,13.1,P ＜ 0.05).The expression levels of VEGF and RGS5 wereincreased in RT group but was reduced in ES group and ES + RT group,and the expressions of VEGF and RGS5 in ES group and ES + RT group had no significant difference (P ＞ 0.05).Rank correlation analysis showed the expression of HIF-1α and the expressions of VEGF and RGS5 were positively correlated (r =0.57,0.71,P ＜ 0.05).Conclusions A possible mechanism of Endostar combined with radiotherapy on tumor growth inhibition may due to the inhibition of HIF-1α and its downstream VEGF and RGS5,and then inhibit tumor angiogenesis that results in the recovery of tumor blood vessels and tumor oxygen supplement.
ABSTRACT
Objective To investigate the relationship between the expression level of microRNA-145 (miR-145) in peripheral blood and clinicopathological characteristics of esophageal cancer patients and evaluate its significance in short-term efficacy of radiotherapy.Methods A total of 52 patients with esophageal.cancer diagnosed in Affiliated Hospital of Qingdao University were collected,and all of the patients rec.eived radiotherapy alone.The relative expression level of miR-145 in peripheral blood was detected by using the method of reverse transcriptase polymerase chain reaction (RT-PCR) before radiotherapy.The correlations between the expression of miR-145 and pathological characteristics as well as short-term efficacy of radiotherapy were analyzed.Results In the 52 patients,the relative expression of miR-145 [M(QR)] in peripheral blood of clinical stage Ⅰ-Ⅱ was 3.14 (1.44),higher than that of stage Ⅲ-Ⅳ [1.71 (0.48)],and the difference was statistically significant (Z =-3.002,P =0.003).The expression level of miR-145 was not related with the age (Z =-0.403,P =0.687),gender (Z =-1.179,P =0.238) and history of drinking (Z =-0.389,P =0.697).The expression levels of miR-145 in complete response (CR),partial response (PR) and no change (NC) groups were 3.27 (1.64),1.83 (1.26) and 1.40 (2.51),respectively,and the difference was statistically significant (H =6.567,P =0.038).Conclusion The expression level of miR-145 in peripheral blood is significantly correlated with the clinical stage of esophageal cancer.Its expression level is positively correlated with the short-term efficacy of esophageal cancer radiotherapy.High expression of miR-145 shows a better short-term efficacy of radiotherapy.
ABSTRACT
Objective To investigate the effect of hydrogen on radiation-induced acute injury in rat brain.Methods Forty-five mature Sprague-Dawley rats were randomly divided into three groups:saline therapy group,hydrogen therapy group and healthy control group.The whole brain of SD rat was irradiated with single dose of 20 Gy by 4 MeV electrons.Rats in therapy group were injected with hydrogen-rich saline after irradiation and were sacrificed at 1,3,7,14 d post-irradiation.The changes of malonaldehyde (MDA),superoxidase dismutase (SOD) and 8-hydroxydeoxygunosine (8-OHdG) in brain homogenate and the pathological changes in brain hippocampus were observed.Results The brain water content (t=3.78,3.18,P＜0.05) and the contents of 8-OHdG (t=2.33,2.71,2.33,P＜0.05) in the therapy group was lower than the control group at 7 d and 14 d post-irradiation.The contents of SOD were significantly higher(t =2.41-2.92,P ＜ 0.05) from 1 to 7 day,while the contents of MDA were significantly lower in therapy group than those in the control group from 1 to 14 day post-irradiation (t =4.01-6.20,P ＜ 0.05).Moreover,the damage degree in the nerve cells of hippocampus was less compared to the control group.Conclusions The hydrogen-rich saline could have protection role in irradiation-induced acute brain injury in rats.