Reports of Practical Oncology and Radiotherapy最新文献

Background: The biological effects and clinical consequences of out-of-field radiation in peripheral organs can be difficult to determine, especially for low doses (0.1 Gy-1 Gy). In recent years, Monte Carlo (MC) methods have been proposed to more accurately predict nontarget doses. The aim of the present study was to assess the feasibility of using Monte Carlo methods to predict the biological response of tissues and critical organs to low dose radiation (0.1 to 1 Gy) based on results published in the literature.

Materials and methods: Literature review, including studies published by our group.

Results and conclusions: It has long been assumed that radiation doses to peripheral organs located far from the target volume are too low to have any clinical impact. In recent years, however, concerns about the risk of treatment-induced secondary cancers, even in peripheral organs, have continued to grow in line with increasing life expectancy. At present, it is difficult in routine calculations to accurately determine radiation doses to the whole body and peripheral organs. Moreover, the potential clinical impact of these doses remains uncertain and the biological response to low dose radiation depends on the organ. In this context, MC methods can predict biological response in those organs. Monte Carlo methods have become a powerful tool to better predict the consequences of interactions between ionising radiation and biological matter. MC modelling can also help to characterise microscopic system dynamics and to provide a better understanding of processes occurring at the cellular, molecular, and nanoscales.

Background: Dynamic conformal arc therapy (DCAT) and volumetric modulated arc therapy (VMAT) can achieve near equal plan quality in single-isocenter multiple target stereotactic radiosurgery (SRS) for brain metastases. This study aimed to investigate the impact of multi-leaf collimator (MLC) errors during beam delivery on the dose distribution for each technique.

Materials and methods: A 10-mm diameter delineation of the three targets was employed on the computed tomography images of a head phantom, and the reference plans were created using the DCAT and VMAT. We simulated the systematic opened and closed MLC errors. 10 MLC error plans with different magnitudes of errors were created in each technique. We investigated the relationship between the magnitude of MLC errors and the change in dose-volume histogram parameters of the targets and normal brain tissue.

Results: The percentage change in the D_98% (Gy) and D_0.1% (Gy) of the target per millimeter of the MLC errors were 13.3% and 2.7% for the DCAT and 15.3% and 9.3% for the VMAT, respectively. The fluctuations of the maximum dose were very small for the DCAT compared to the VMAT. Changes in the V_12Gy (cc) of the normal brain tissue were 47.1%/mm and 53.2%/mm for the DCAT and VMAT, respectively, which are comparable changes for both techniques.

Conclusions: Although the impact of MLC errors on the target coverage and the normal brain tissue is comparable for both techniques, the internal dose of the targets generated by the DCAT technique is robust to the MLC errors.

Background: Cancer stem cells (CSCs) constitute a small and elusive subpopulation of cancer cells within a tumor mass and are characterized by stem cell properties. Reprogrammed CSCs exhibit similar capability to initiate tumor growth, metastasis, and chemo- and radio-resistance and have similar gene profiles to primary CSCs. However, the efficiency of cancer cell reprogramming remained relatively low. There is limited literature available on the reprogramming of lung cancer cells. Hence, in this study we have conducted reprogramming of human lung cancer cells towards more benign type of cells.

Materials and methods: The reprogramming process was carried out with the use of STEMCCA vector. We have investigated the gene expression profile of induced CSCs (iCSCs) using the microarray technique.

Results: The lung iCSCs demonstrate morphology characteristics of induced pluripotent stem cells (iPSCs) and gene expression profile that significantly differ from cells before reprogramming. We have also presented the elevated level of expression of genes associated with the cancer stemness and thus revealed new interesting CSC-like molecular markers.

Conclusions: These preliminary results demonstrated that the reprogramming process in vitro leads to the remarkable changes in cells at the gene level and has potential to be an alternative method of generating CSC-like cells.

Background: The primary treatment of metastatic spine disease is radiation therapy (RT), traditionally conventional external beam RT (EBRT) or stereotactic body RT (SBRT). Until recently, there had been no Level 1 evidence supporting SBRT over EBRT, which has led to difficulties obtaining insurance approval. Publication of the first randomized controlled trial (RCT) comparing SBRT to EBRT for spine metastases [Canadian Cancer Trials Group (CCTG)] helped change this. The results showed superiority of SBRT in pain response; however, the results were not cited by The National Comprehensive Cancer Network (NCCN) until March 24, 2023. We present results from an ongoing RCT to assess the impact of this NCCN inclusion on insurance denials for trial-eligible patients.

Materials and methods: The ongoing SPORTSMEN RCT randomizes metastatic spine cancer patients to SBRT versus EBRT. Trial-eligible patients during the first six months were examined to assess if SBRT was denied by insurance before March 24, 2023, versus afterwards. Fisher's exact test was used to assess for statistical significance.

Results: Prior to CCTG NCCN inclusion, 25% of 12 trial-eligible patients experienced SBRT insurance denial. Following NCCN inclusion, of 8 patients, one (12.5%) has undergone insurance denial of SBRT. These differences were not statistically significant.

Conclusions: The inclusion of Level 1 evidence in the NCCN guidelines has resulted in a numerical halving of spine SBRT insurance denials on a RCT, with the small sample size likely the largest culprit of not meeting statistical significance. These findings illustrate the importance of generating high-quality evidence, followed by timely inclusion into the NCCN guidelines.

Multi-omics approaches are revolutionizing cancer research and treatment by integrating single-modality omics methods, such as the transcriptome, genome, epigenome, epi-transcriptome, proteome, metabolome, and developing omics (single-cell omics). These technologies enable a deeper understanding of cancer and provide personalized treatment strategies. However, challenges such as standardization and appropriate methods for funneling complex information into clinical consequences remain. The tumor microenvironment (TME) is a complex system containing cancer cells, immune cells, stromal cells, and secreted molecules. To overcome these challenges, researchers can establish standardized protocols for data collection, analysis, and interpretation. Collaborations and data sharing among research groups and institutions can create a comprehensive and standardized multi-omics database, facilitating cross-validation and comparison of results. Multi-omics profiling enables in-depth characterization of diversified tumor types and better reveal their function in cancer immune escape. Datasets play a fundamental role in multi-omics approaches, with artificial intelligence and machine learning (AI) rapidly advancing in multi-omics for cancer.

Background: The objective was to evaluate the efficacy and safety of radiotherapy and the prognostic factors in patients with esophageal cancer who received definitive radiotherapy, using volumetric modulated arc therapy (VMAT).

Materials and methods: Forty-seven patients who received definitive radiotherapy using VMAT between September 2017 and December 2020 were enrolled. Prescription doses were 60 Gy in 30 fractions to the planning target volume (PTV) primary and 48 Gy in 30 fractions to the PTV subclinical. Overall survival (OS), progression free survival (PFS), and toxicity were analyzed, and univariate and multivariate analyses were used to investigate the prognostic factors.

Results: Median follow up time was 10 months. Most of the patients had an advanced disease stage (stage I, 12.8%; II, 8.5%; III, 27.7%; IV, 51.0%) patients (38.3%) had a T4 tumor. The median survival time was 14 months (range: 0-56 months). The 2-year OS and PFS were 31.3% and 20.4%, respectively. Acute adverse events (≥ Grade 3) were observed in 25 patients (53.2%), and the most frequent types were dysphagia, hematological toxicities including leukopenia, and febrile neutropenia in 14 (29.8%), 10 (21%), and 10 (21%) patients, respectively. Late adverse events (Grade 3 or higher) were observed in eight patients (17.0%), and the most frequent types were pneumonitis in four patients (8.5%), and Grade 5 in one patient (2.1%; esophageal fistula). In multivariate analysis, neutrophil-to-lymphocyte ratio (NLR) > 3 (p = 0.026) was significantly associated with poor survival.

Conclusion: Definitive radiotherapy of 60Gy with VMAT is feasible and safe for patients with esophageal cancer. Pre-treatment NLR >3 was an independent prognostic factor for OS.

Background: Although there have been various attempts to find appropriate treatment from best conservative care to multimodal treatments, curative outcomes remain poor.

Materials and methods: 30 patients with primary and secondary malignant tumors of the pleura were treated in the Radiotherapy Clinic of USHATO during the period from December 2016 to April 2023. Video-assisted thoracoscopic surgery (VATS) and talc pleurodesis was performed in 18 patients (60%). In all patients, radiotherapy for the pleura was performed on a helical tomotherapy machine. In 21 patients (70%), normal fractionated radiotherapy was performed at daily dose of 1.8-2 Gy to total dose of 40 Gy (5 times a week), and in 6 patients (20%), integrated surdosage to 50 Gy was also performed for visible lesions. Hypofractionated radiotherapy (10 fractions of 3 Gy and 4 fractions of 4 Gy) was performed in 3 (10%) patients.

Results: Patients were followed up from 1 month to 57 months (median 14 months) or until death. The observed median survival for all patients was 19.2 months [95% confidence interval (CI): 11.5-26.9] (Fig. 3). The 1-, 2- and 3-year survival rates were 40%, 23% and 7% of patients, respectively. Malignant mesothelioma patients had 1-, 2- and 3-year survival rates of 31%, 10% and 0%, respectively. The 1-, 2-, and 3-year survival rates for patients with secondary malignancies were 54%, 45%, and 18%, respectively.

Conclusion: Our results suggest that helical tomotherapy is a feasible therapeutic option for patients with malignant mesothelioma or malignant secondary pleural involvement with a reasonable toxicity profile relative to other unaffected lung.

Background: Osteoblastoma (OB) is a rare benign bone tumor, mainly affecting adolescents and young adults. It's commonly found in the spine and long bones, with a male-to-female ratio of 2:1. Surgery, primarily en bloc resection or curettage, is the main treatment. Radiotherapy (RT) or systemic treatment is considered in specific cases. However, optimal RT strategies remain unclear due to limited and outdated data. This study aims to evaluate RT role, efficacy, and safety in treating OB.

Matrials and methods: The study group was a cohort of consecutive patients with OB treated in our institute that received RT in years 1998-2023. We analyzed indication for RT, irradiated site, RT technique, total dose, dose per fraction, early and late tolerance, and survival.

Results: Thirteen patients meeting the criteria were analyzed. Most were males (10 out of 13) with a median age of 21. Most OBs were within the vertebral column. All patients received definitive RT for unresectable disease and underwent conventionally fractionated RT (1.8-2.0 Gy per fraction) to total doses 40-70.2 Gy. Only mild acute toxicity was observed. No late toxicity was reported. The median follow-up was 118 months. Local progression was observed in four patients, all of whom died.

Conclusions: RT is a valuable option for certain OB patients ineligible for surgery. Seeking treatment at specialized bone tumor centers with RT techniques is crucial due to OB's rarity and the lack of standardized guidelines. Recommended RT doses fall between 50-70 Gy using intensity-modulated techniques in conventional 1.8-2 Gy fractions.

Background: Recent advances in stereotactic body radiation therapy (SBRT) technology for early-stage peripheral lung cancer have been remarkable and are becoming a viable alternative to surgery. However, the most important problem in performing SBRT correctly is minimizing the respiratory motion of the tumor.

Materials and methods: Thirty-eight patients treated with SBRT were evaluated to clarify factors affecting respiratory motion of early-stage peripheral lung cancer in the management of restrictive breathing technique (abdominal compression) to reduce respiratory tumor motion in SBRT. We investigated age, gender, body mass index (BMI), Brinkman index (BI), forced expiratory volume in 1 second (FEV 1.0), and type of ventilatory impairment as patient factors, and T-factor, stage, tumor-bearing lung lobe, and tumor pathology as tumor factors. Respiratory motion was assessed by volume differences between clinical target volume (CTV) and internal target volume (ITV). The degree of tumor motion due to respiration was compared using the formula of (ITV-CTV)/CTV as an index.

Results: In the results, univariate analyses showed that only age was a significant predictor of respiratory tumor motion (p = 0.048). In multi-variate analyses, only T factor was an independent significant predictor of respiratory tumor motion (p = 0.045), while there was a significant trend for age (p = 0.061), and tumor location (p = 0.067).

Conclusions: In late elderly patients or T1a tumor, respiratory motion in early-stage peripheral lung cancer was significantly large. However, it is not predictable by patient and tumor characteristics. Therefore, respiratory motion of the tumor should be measured in all patients in some way.