BackgroundThe purpose of this study was to perform a dosimetric comparison between proton beam therapy (PBT) and photon radiation therapy in patients with locally advanced esophageal squamous cell carcinoma (ESCC) who were treated with PBT in our institution. In addition, we evaluated the correlation between toxicities and dosimetric parameters, especially the doses to normal lung or heart tissue, to clarify the clinical advantage of PBT over photon radiation therapy.MethodsA total of 37 consecutive patients with Stage III thoracic ESCC who had received PBT with or without concurrent chemotherapy between October 2012 and December 2015 were evaluated in this study. The dose distributions of PBT were compared with those of dummy 3-dimensional conformal radiation therapy (3DCRT) and Intensity Modulated Radiation Therapy (IMRT), focusing especially on the doses to organs at risk, such as normal lung and heart tissue.ResultsOf the 37 patients, the data from 27 patients were analyzed. Among these 27 patients, four patients (15%) developed grade 2 pericardial effusion as a late toxicity. None of the patients developed grade 3 or worse acute or late pulmonary and cardiac toxicities. When the dosimetric parameters between PBT and planned 3DCRT were compared, all the PBT domestic variables for the lung dose except for lung V10 GyE and V15 GyE were significantly lower than those for the dummy 3DCRT plans, and the PBT domestic variables for the heart dose were also significantly lower than those for the dummy 3DCRT plans. When the PBT and IMRT plans were compared, all the PBT domestic variables for the doses to the lung and heart were significantly lower than those for the dummy IMRT plans. Regarding the correlation between the grades of toxicities and the dosimetric parameters, no significant correlation was seen between the occurrence of grade 2 pericardial effusion and the dose to the heart.ConclusionsWhen the dosimetric parameters of the dose distributions for the treatment of patients with locally advanced stage III ESCC were compared between PBT and 3DCRT or IMRT, PBT enabled a significant reduction in the dose to the lung and heart, compared with 3DCRT or IMRT.
BackgroundCellular responses to proton beam irradiation are not yet clearly understood, especially differences in the relative biological effectiveness (RBE) of high-energy proton beams depending on the position on the Spread-Out Bragg Peak (SOBP). Towards this end, we investigated the differences in the biological effect of a high-energy proton beam on the target cells placed at different positions on the SOBP, using two human esophageal cancer cell lines with differing radiosensitivities.MethodsTwo human esophageal cancer cell lines (OE21, KYSE450) with different radiosensitivities were irradiated with a 235-MeV proton beam at 4 different positions on the SOBP (position #1: At entry; position #2: At the proximal end of the SOBP; position #3: Center of the SOBP; position #4: At the distal end of the SOBP), and the cell survivals were assessed by the clonogenic assay. The RBE10 for each position of the target cell lines on the SOBP was determined based on the results of the cell survival assay conducted after photon beam irradiation. In addition, the number of DNA double-strand breaks was estimated by quantitating the number of phospho-histone H2AX (γH2AX) foci formed in the nuclei by immunofluorescence analysis.ResultsIn regard to differences in the RBE of a proton beam according to the position on the SOBP, the RBE value tended to increase as the position on the SOBP moved distally. Comparison of the residual number of γH2AX foci at the end 24 h after the irradiation revealed, for both cell lines, a higher number of foci in the cells irradiated at the distal end of the SOPB than in those irradiated at the proximal end or center of the SOBP.ConclusionsThe results of this study demonstrate that the RBE of a high-energy proton beam and the cellular responses, including the DNA damage repair processes, to high-energy proton beam irradiation, differ according to the position on the SOBP, irrespective of the radiosensitivity levels of the cell lines.Electronic supplementary materialThe online version of this article (doi:10.1186/s13014-017-0849-1) contains supplementary material, which is available to authorized users.
We evaluated the failure pattern after definitive chemoradiotherapy in patients with stage III nonesmall-cell lung cancer harboring epidermal growth factor receptor mutations and/or anaplastic lymphoma kinase translocation. Although the epidermal growth factor receptor-mutant group showed a lower incidence of infield failure and higher incidence of out-of-field failure, the group with anaplastic lymphoma kinase translocation showed no characteristic in-field or out-of-field failure pattern. Introduction: This study was aimed at clarifying the failure pattern after definitive chemoradiotherapy in patients with stage III nonesmall-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations and/or anaplastic lymphoma kinase (ALK) translocation. Methods and Materials: This retrospective study was a singleinstitution study conducted on patients with unresectable stage III non-squamous NSCLC treated by definitive chemoradiotherapy between January 2006 and March 2016. Only patients with information of EGFR mutations and/or ALK translocation were included. The prognosis and initial recurrence patterns were compared according to the presence/absence of EGFR mutation and/or ALK translocation. Results: A total of 173 patients (34 with activating EGFR mutations, 13 who were positive for ALK translocation) were enrolled, and the median follow-up duration was 36 months (range, 3-123 months). The 3-year overall survival rate was significantly higher in the EGFR-mutant group than in the wild-type EGFR group (75% vs. 46%; P ¼ .002). There was a tendency towards a better overall survival in the ALK-positive group than in the ALK-negative group (68% vs. 44%; P ¼ .085). No differences in the 3-year progression-free survival were observed according to the EGFR or ALK status. The EGFR-mutant group showed a significantly lower rate of in-field failure (P ¼ .027) and higher rate of out-of-field failure (P ¼ .029) as compared with the wild-type EGFR group. There was no significant difference in the rate of in-field failure or out-of-field failure between the ALK-positive and ALK-negative groups. Conclusions: Although the ALK-positive group showed no characteristic failure pattern, the EGFR-mutant group showed a lower rate of in-field failure and higher rate of out-of-field failure.
Background: The standard treatment for patients with unresectable locally advanced esophageal squamous cell carcinoma (ESCC) is definitive chemoradiotherapy (CRT) using 5-FU plus cisplatin. However, complete response (CR) rates are low at 11-25%, resulting in 9-10 months of median overall survival (OS). An improved therapeutic efficacy by combining immunotherapy with radiation has been reported in patients with locally advanced non-small cell lung cancer. The results using ESCC cell lines suggest sequential treatment with anti-PD-L1 agents soon after completion of CRT is the most effective combination.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.