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Editorial13 March 2024
Editorial: Methods in radiation oncology
Amirhosein Kefayat, Mahshid Bahrami, Mojtaba Karamiand Fatemeh Ghahremani

In recent years, radiotherapy has played a critical role for cancer patients' treatment. Recently different radiotherapy methods have emerged and different studies have tried to maximize their efficacy while limiting their disadvantage [1]. In this research topic editorial letter, we tried to address the most recent methods of radiotherapy, how they can conquer current challenges in different cancer radiation therapy, their therapeutic efficacy, and probable weakness.Radiotherapy always has been a well-known treatment options for esophageal cancer patients who are not candidates for surgery. Two methods of radiation therapy including, involved field irradiation (IFI) and elective nodal irradiation (ENI) has been widely investigated for esophageal cancer. elective lymph node irradiation (ENI) aim is to irradiate to an area that has not been metastasized to decrease chance of metastasis formation which can improve local area control but did not improve overall survival (OS). On the other hand, ENI can increase risk of treatmentrelated adverse events. IFI irradiates only the affected area to limit the area of irradiation.According to the metanalysis published in our research topic [2], IFI offers significant improvements in overall survival rates at 5 years compared to ENI. While, it is associated with a notable decrease in the incidence of grade ≥2 acute esophagitis and grade ≥3 acute esophagitis, highlighting its potential to reduce treatment-related adverse events. The findings introduce IFI as a promising treatment method for esophageal cancer patients undergoing definitive radiotherapy or chemoradiotherapy.Stereotactic body radiotherapy (SBRT) has been employed as a deeply effective treatment modality for lung cancer which not only can deliver precise radiation dose to the tumor site but also offer minimal damage to surrounding healthy tissues [3]. However, intrafraction motion during SBRT can lead to target dose discrepancies, compromising treatment efficacy. Therefore, many research studies have focused on investigating the impact of intrafraction variation on target dose distribution in lung SBRT. The main issue in the lung SBRT is respiratory-induced target motion can lead to tumor geometric uncertainty and consequent reduction in the local control and increase the chance of off-target radiation delivery to nearby organs. Thus, respiratory motion must be managed and controlled during treatment. In this research topic one of the evaluated radiation therapy methods is SBRT for lung and we underscored the importance of accounting for motion effects in SBRT treatment planning to ensure optimal dose delivery and treatment outcomes. This motion issue during fractions of radiation therapy has been mentioned for different tumors especially in the respiratory and gastrointestinal system while knowledge methods have introduced to solve this problem. Accurate monitoring of intrafraction tumor motion is an option for ensuring precise radiation dose delivery during radiotherapy and recent studies have investigated the accuracy of ultrasound tracking for monitoring tumor motion in real-time in pancreas tumor.Researcher demonstrated that ultrasound tracking exhibits high accuracy in tracking tumor motion and ultrasound tracking may represent a potential method for real-time monitoring of targets during radiotherapy, facilitating more accurate delivery of radiation doses and improving treatment outcomes for patients with pancreatic cancer and other tumors which move during irradiation and ultrasonography is possible for their traction [4].Proton pencil beam scanning (PBS) transmission has gained a lot of interest as a potential treatment modality for lung cancer as it exhibits high toxicity-sparing effects and improved treatment outcomes. Plan quality and robustness of proton PBS transmission FLASH delivery in lung cancer treatment has been a hot topic so far for research studies. In this research topic we found out that while transmission plans have yielded slightly inferior plan quality compared to conventional proton SBRT plans, they have demonstrated improved robustness and potential for toxicity-sparing effects. By employing more beams, both dose and dose-rate robustness for transmission plans can be achieved, offering promising prospects for enhancing treatment efficacy and minimizing treatment-related adverse events in lung cancer patients [5].In conclusion, the evolution of radiotherapy in recent years has been instrumental in advancing cancer treatment options. As highlighted in this editorial letter, various radiotherapy methods have emerged, each with its unique strengths and challenges. From the promising outcomes of IFI in esophageal cancer to the challenges of managing intrafraction motion in SBRT for lung cancer, researchers continue to innovate and refine treatment strategies. Additionally, the potential of ultrasound tracking and proton pencil beam scanning (PBS) transmission offers further avenues for improving treatment outcomes and minimizing adverse events. Overall, these advancements underscore the ongoing commitment to enhancing radiotherapy efficacy while prioritizing patient care and safety.

2,485 views

ORIGINAL RESEARCH
18 October 2023
The expression of Ki-67 and Glypican -3 in hepatocellular carcinoma was evaluated by comparing DWI and 18F-FDG PET/CT
Xuedong Wang, 2 more and Min Chen
The expression of Ki-67 and Glypican -3 in hepatocellular carcinoma was evaluated by comparing DWI and 18F-FDG PET/CT
Objective: The value of DWI and 18 F-FDG PET/CT in evaluating the expression of Ki-67 and GPC-3 in hepatocellular carcinoma (HCC ) was compared.Materials and methods: Ninety-four patients with primary HCC confirmed by pathology were retrospectively divided into high-and low-Ki-67-expression and positive-and negative-Glypican (GPC)-3 groups. The ADC and SUVmax values of the lesions in both groups were measured. Receiver operating characteristic (ROC) curves were used to evaluate the identification efficiency of parameters with significant differences for each group of lesions, and the area under the curve (AUC) was calculated. The combined ADC and SUVmax values were analyzed by binary logistic regression. The Delong test was used to compare the AUC values of the combined and single parameters. Pearson (in line with normal distribution) or Spearman (in line with abnormal distribution) correlation analysis was used to analyze the correlation.The ADC value of the high-Ki-67-expression group was lower than that of the low-Ki-67-expression group (P<0.05), and the SUVmax value of the high-expression group was higher than that of the low-expression group (P<0.05). The ADC value of the positive-GPC-3 group was lower than that of the negative group (P<0.05), and the SUVmax value of the positive group was higher than that of the nega.tive group (P< 0.05). The combined ADC and SUVmax values in the GPC-3 group were better than those of a single parameter (P<0.05). There was a strong negative correlation between the SUVmax value and ADC value in the Ki-67 group (R=-0.578, P<0.001) and a weak negative correlation between the SUVmax value and ADC value in the GPC-3 group (R=-0.279, P=0.006). The SUVmax value was strongly positively correlated with the Ki-67 expression index (R=0.733, P<0.001), while the ADC value was strongly negatively correlated with the Ki-67 expression index (R=-0.687, P<0.001).Conclusion: DWI and 18 F-FDG PET/CT can be used to evaluate the expression of Ki-67 and GPC-3 in HCC, and there is a certain orrelation between the ADC value and SUVmax. Combined DWI and 18 F-FDG PET/CT is superior to a single technique in evaluating the expression of GPC-3 in HCC patients. However, the combined model did not benefit the Ki-67 group..

3,442 views

10 citations

Purpose: Modern Linacs are equipped with multiple photon energies for radiation therapy, and proper energy is chosen for each case based on tumor characteristics and patient anatomy. The aim of this study is to investigate whether it is necessary to have more than two photons energies. Methods: The principle of photon energy synthesis is presented. It is shown that a photon beam of any intermediate energy (Esyn) can be synthesized from a linear combination of a low energy (Elow ) and a high energy (Ehigh). The principle is validated on a wide range of scenarios: different intermediate photon energies on the same Linac; between Linacs from the same manufacturer or different manufacturers; flat and non-flat beams; and extensive photon energies available from published reference data. In addition, 3D dose distributions in water phantom are compared using Gamma analysis. The method is further demonstrated in clinical cases of various tumor sites and multiple treatment modalities. Experimental measurements are performed for IMRT plans and they are analyzed using the standard clinical protocol. Results: The synthesis coefficients vary with energy and field size. The root mean square error (RMSE) is within 1.1% for open and wedge fields. Excellent agreement was observed for BJR data with an average RMSE of 0.11%. The 3D Gamma analysis shows a good match for all field sizes in the water phantom and all treatment modalities for the five clinical cases. The minimum gamma passing rate of 95.7% was achieved at 1%/1mm criteria for two measured dose distributions of IMRT plans. Conclusion: A Linac with two photon energies is capable of producing dosimetrically equivalent plans of any energy in-between through the photon energy synthesis, supporting the notion that there is no need to equip more than two photon energies on each Linac. This can significantly reduce the cost of equipment for radiation therapy.

5,796 views

3 citations

ORIGINAL RESEARCH
8 December 2022
Simulation of dosimetric consequences of intrafraction variation of tumor drift in lung cancer stereotactic body radiotherapy
Bin Han, 6 more and Yuexin Guo

1,770 views

7 citations

The role of involved field irradiation versus elective nodal irradiation in definitive radiotherapy or chemoradiotherapy for esophageal cancer- a systematic review and meta-analysis
SYSTEMATIC REVIEW
2 November 2022
The role of involved field irradiation versus elective nodal irradiation in definitive radiotherapy or chemoradiotherapy for esophageal cancer- a systematic review and meta-analysis
Hesong Wang, 3 more and Wenbin Shen
Objective: This study aimed to analyze whether involved field irradiation (IFI) is associated with improving survival outcomes and reducing adverse events compared with elective nodal irradiation (ENI) in patients of esophageal cancer who underwent definitive radiotherapy or chemoradiotherapy. Summary Background Data: Radiotherapy plays an important role for not surgery patients. However, the role of radiation target size is still uncertain. Methods: We searched Web of Science, Embase, PubMed, and Cochrane Central for English and non-English publications comparing esophageal cancer patients who received radiotherapy with IFI with those with ENI. Primary outcomes included overall survival (OS) and adverse events related to radiotherapy. The risk of bias was assessed using the Cochrane Risk of Bias tool for randomized studies and the Newcastle-Ottawa Scale and Agency for Healthcare Research and Quality Standard for non-randomized studies. We evaluated the certainty of evidence by Grading of Recommendations, Assessment, Development, and Evaluation. Results: Totally, 23 studies with 4120 patients were included. IFI group demonstrated significant improvement in the OS rates at 5 years, but not at 1, 2, and 3 years, compared with the ENI group (pooled Risk Ratio [RR], 0.78; 95% confidence interval [CI], 0.68–0.90; P = 0.0004; high certainty). In addition, IFI demonstrated a significant decrease in the incidence of grade ≥2 acute esophagitis (AE) (pooled RR, 0.79; 95% CI, 0.69–0.90; P = 0.0005; high certainty) and grade ≥3 AE (pooled RR, 0.51; 95% CI, 0.38–0.69; P < 0.00001; high certainty) compared with ENI, but not in the incidence of grades ≥3 acute pneumonia, late esophagitis, and late pneumonia. Conclusions: Compared to ENI, IFI demonstrated significant improvement in OS at 5 years. The addition of intensity-modulated radiotherapy (IMRT) to IFI increased the 5-year OS; however, similar results were not observed with the addition of three-dimensional conformal radiotherapy to IFI and ENI. Furthermore, IFI demonstrated a significant decrease in grade ≥2 and grade ≥3 AE, while IMRT demonstrated no difference in the incidence of grade ≥3 AE. IFI and ENI do not differ in the incidence of grades ≥3 acute pneumonia, late esophagitis, and late pneumonia.

4,339 views

17 citations

METHODS
20 October 2022
Population-level and individual-level explainers for propensity score matching in observational studies
Debashis Ghosh, 2 more and Sana D. Karam

2,813 views

3 citations

ORIGINAL RESEARCH
27 September 2022
A phantom-based analysis for tracking intra-fraction pancreatic tumor motion by ultrasound imaging during radiation therapy
Tianlong Ji, 12 more and Kai Ding

2,728 views

1 citations

Dose rate and dose robustness for proton transmission FLASH-RT treatment in lung cancer
ORIGINAL RESEARCH
15 August 2022
Dose rate and dose robustness for proton transmission FLASH-RT treatment in lung cancer
Shouyi Wei, 12 more and Minglei Kang

3,984 views

25 citations