Reports of Practical Oncology and Radiotherapy最新文献

Background: This study evaluates the long-term outcomes of re-irradiation (Re-RT) using intensity-modulated radiotherapy (IMRT) in patients with locally recurrent or second primary (SP) head and neck cancer (HNC). We aimed to assess locoregional control (LRC), overall survival (OS), and toxicity profiles over a 13-year period, identifying factors influencing treatment outcomes.

Materials and methods: We retrospectively analyzed records of 178 patients who underwent Re-RT with IMRT at our institution between January 2010 and October 2023. Re-RT was delivered as adjuvant or definitive treatment. Inclusion criteria included squamous cell carcinoma histology and a performance status of ≥ 2. Patients with unresectable clinical T3/T4 or node-positive disease received concurrent chemotherapy. Primary endpoints were LRC and OS, analyzed using univariate and multivariate Cox regression models. Late toxicity was assessed with a focus on functional outcomes and serious late adverse events.

Results: The median follow-up was 39.7 months [95% confidence interval (CI): 32.651-46.277]. The median LRC was 11.23 months (95% CI: 6.845-15.627), with a 3-year LRC rate of 21.9%. The median OS was 26.5 months (95% CI: 21.099-31.411), with a 3-year OS rate of 31.7%. Better LRC was associated with a time interval of > 2 years between RT courses and absence of nodal involvement. Improved OS was associated with adjuvant Re-RT and a time interval of ≥ 2 years. Toxicity analysis revealed manageable late toxicities.

Conclusion: Re-irradiation with IMRT is effective for locally recurrent or SP HNC, offering promising survival outcomes with manageable toxicity. Proper patient selection and time intervals between RT courses are critical to optimizing outcomes.

Background: The study explores the role of non-coding ribonucleic acids (ncRNAs) and higher enhancer of zeste homolog 2 (EZH2) gene in breast cancer progression, examining how microRNA (miRNA) and long noncoding RNA (lncRNA) control EZH2, potentially influencing oncogene growth and treatment failure.

Materials and methods: The databases used in the study included Cyclebase 3.0 and CellTracer to determine EZH2's role in cell cycle, Oncomine, OncoMX and The University of Alabama At Birmingham Cancer Data Analysis Portal (UALCAN) for Pan-cancer analysis, The Cancer Genomic Atlas Portal (TCGA Portal), Gene Expression Profiling Interactive Analysis (GEPIA2), OncoDB, CR2Cancer, Encyclopaedia of RNA Interactomes (ENCORI), and The Cancer Genome Altas Analyzer (TCGAnalyzeR v1.0) for differential expression analysis, CR2Cancer, OncoDB, MethMarkerDB, and Wanderer databases for epigenetic alteration analysis, Kaplan-Meier Plotter for survival analysis, Breast Cancer Gene Expression Miner (bc-GenExMiner v5.0) for hormone receptor analysis, Tumor-Immune System Interaction Database (TISIDB), Cancer Single Cell State Atlas (CancerSEA), TNMplot, DriverDBv4, and ENCORI for biological processes, cell cycle checkpoints and metastasis analysis, Enrichr, Tumor Immune Estimation Resource (TIMER 2.0), Gepia2 for transcription factor analysis, miRNet, Transcriptome Alterations in Cancer Omnibus (TACCO), and CancerMIRome for miRNA analysis, Enrichr, UALCAN, and ENCORI for lncRNA analysis.

Results: The EZH2 gene is overexpressed in breast cancer (BRCA) tumors, metastatic tissues, and circulating tumor cells, potentially leading to cancer progression. Patients with high EZH2 expression have shorter overall survival (OS), distant metastasis-free survival (DMFS), and relapse-free survival (RFS) compared to those with low expression. Estrogen receptot (ER)-negative BRCA tumors and PR-negative tumors have high EZH2 gene and eukaryotic transcription factor (E2F2) levels. The EZH2/E2F2 axis may assist ER/PR-negative BRCA by sponging homosapiens microRNA family (hsa-let-7b-5p) through lncRNA-thymopoietin antisense transcript 1 (TMPO-AS1). Overexpression of the EZH2 protein is associated with BRCA metastasis.

Conclusion: EZH2 overexpression in basal-like BRCA is mediated by a competing endogenous RNA (ceRNA) network and regulating their expression levels may facilitate better survival outcomes.

Background: Existing calibration procedures of ionization chambers refer to the cobalt 60 (⁶⁰Co) beam and require a k _Q quality conversion factor for therapeutic photon beams. This factor has the largest contribution to the total standard uncertainty of dose measurement. The main objective of our work is to verify the performance of the experimental DW2 ionization chamber for the absorbed dose to water measurements using Monte Carlo (MC) calculations instead of calibration in the Secondary Standard Dosimetry Laboratory (SSDL).

Materials and methods: To calculate the absorbed dose to water based on the signal from the experimental DW2 ionization chamber, its active volume was determined. Using experimental methods, the correction factors for polarisation and ion recombination were established. Additionally, MC methods were employed to determine the factors for converting the ionization charge in the chamber cavity to the absorbed dose to water. Subsequently, the chamber's performance was verified against ionometric and calorimetric Central Office of Measures (GUM) standards under reference conditions.

Results: The difference between the dose measured by the DW2 chamber and the GUM ionometric standard for the ⁶⁰Co beam was -0.09%. The differences for the 6, 10 and 15 MV photon beams relative to the graphite calorimeter were -0.30%, 0.40%, and 0.45%, respectively. The maximum expanded (k = 2) standard uncertainty of the chamber was 0.57%.

Conclusions: This work demonstrates that it is possible to obtain accurate measurements of the absorbed dose to water for high-energy photon beams under reference conditions using an ionization chamber without calibrating it in a ⁶⁰Co source but only using correction factors determined by MC calculations.

Background: The aim of the study was to analyze the individual doses received by the staff of the Nuclear Medicine Department at the Greater Poland Cancer Centre, with a special focus on differences between groups and changes in dose values over time.

Materials and methods: The analysis was performed based on radiation exposure doses from the reports of accredited laboratory received by the Nuclear Medicine Department personnel in the Greater Poland Cancer Centre between 2008-2023. The nuclear medicine staff was divided into 5 groups: nurses, medical secretaries, nuclear medicine physicians, cleaning personnel and nuclear medicine radiographers further divided into two subgroups: those preparing radiopharmaceuticals and performing examinations (Group A) and those who perform only examinations (Group B).

Results: It was found that personnel who had contact with radioisotopes, i.e., the nurses and radiographers who prepare the radiopharmaceuticals, received higher doses than other employees. However, despite the increase, all employees of the Department receive doses below the limits resulting from the legal regulation.

Conclusion: In this study we found that nurses and radiographers handling radiopharmaceuticals receive higher radiation doses than other employees. The study advocates for further research into advanced protective measures and technologies to enhance safety in nuclear medicine practices.

Background: This review examines the role of rectal spacers in gynecological cancer radiation therapy, highlighting their potential to mitigate radiation-induced toxicities, improve treatment precision, and enhance patient quality of life. The analysis explores different spacer materials, insertion techniques, and clinical applications while addressing current challenges and limitations.

Materials and methods: A systematic review of studies evaluating rectal spacers in external beam radiation therapy (EBRT), brachytherapy, and stereotactic body radiation therapy (SBRT) for gynecological malignancies was conducted using PubMed, Scopus, and Embase. The review includes prospective and retrospective studies, clinical trials, and case reports from 2005-2024. Keywords used were "rectal spacers", "gynecological cancer radiotherapy", and "hydrogel spacers".

Results: Rectal spacers demonstrate significant dosimetric advantages in reducing rectal dose exposure in gynecological cancers, particularly in brachytherapy. However, the spacer placement area overlaps with the clinical target volume (CTV), necessitating careful consideration in treatment planning. The integration of rectal spacers in SBRT is still emerging, with limited clinical data available. Limitations include cost, risk of migration, and patient discomfort. Additionally, cost-effectiveness and routine implementation in clinical practice require further investigation.

Conclusions: While rectal spacers provide significant benefits in reducing toxicity, their role in treatment precision remains debatable. Further research is needed to refine patient selection and cost-effectiveness. Future research should focus on refining patient selection criteria, improving spacer stability, and evaluating long-term clinical and economic impacts.

Background: The global burden of cancer is escalating, with millions of individuals diagnosed and succumbing to the disease each year. Early detection is crucial for improving patient outcomes, yet many cancers are identified at advanced stages. Vimentin (VIM) has emerged as a promising biomarker with significant diagnostic and prognostic potential.

Materials and methods: This study investigates VIM expression and promoter methylation across various cancers using The Cancer Genome Atlas (TCGA) datasets. Additionally, we analyze protein-protein interactions and mutation frequencies using advanced bioinformatics tools.

Results: Our findings reveal that VIM is overexpressed in seven cancer types, including cholangiocarcinoma, glioblastoma multiforme, and breast invasive carcinoma. Notably, VIM expression is correlated with promoter methylation in specific cancers. Furthermore, we identify complex protein interactions involving VIM, highlighting its role in critical cellular processes such as proliferation and apoptosis.

Conclusion: These insights emphasize Vimentin's multifaceted role in cancer, suggesting its potential as both a therapeutic target and a diagnostic marker.

Cancer continues to be a major factor in global mortality rates, presenting a substantial challenge to efforts aimed at extending life expectancies worldwide. Effective cancer treatment necessitates a multidisciplinary approach. India has a limited number of radiotherapy centres, and their distribution is uneven between urban and rural areas. Setting up a radiotherapy department is a complex process that demands thorough planning. The establishment of new radiotherapy departments involves a series of interconnected steps such as regulatory support, site selection, infrastructure design, civil works, recruitment of professional staff, equipment procurement, commissioning, and obtaining licenses. Mobilizing human resources, including training and forming a skilled team consisting of radiation oncologists, medical physicists, technologists, nursing officers, and support staff, is essential for proficient operation and patient care. Effective master planning for new radiotherapy facilities necessitates collaboration and involvement of highly specialized professionals from both the healthcare sector and the construction industry. Conducting a cost-benefit analysis is vital to ensure that the proposed facility meets the institute's objectives in terms of patient workload and clinical capability with sufficient institutional resources to support the program. The strategic placement of functional areas not only improves patient workflow and optimizes shielding needs but also enhances communication within the broader institution. In addition, designing a radiotherapy facility with vision and adaptable expansion capabilities ensures cost efficiency, allowing seamless evolution in response to future demands while maintaining uninterrupted services. Therefore, the article aims to discuss the challenges, and strategies for establishing a new radiation oncology department.

Background: Smoking is linked to high morbidity and mortality rates of lung cancer, emphasizing the need for a better understanding of prognosis-related mRNA/miRNA/lncRNA-ceRNA networks.

Materials and methods: The study utilized databases like OncoMX, The University of ALabama at Birmingham CANcer data (UALCAN), OncoDB, ENCORI, Kaplan-Meier (KM) Plotter, miRNet, CancerMIRNome, TISIDB, and TIMER2.0 to analyze NCAPG/miRNA and LncRNA expression in lung cancer tumors and healthy tissues.

Results: The NCAPG gene is overexpressed in lung cancer cells. High NCAPG expression is associated with adenocarcinoma patients with a log fold change of 8.7 in case of tumor vs. normal samples (t = 515, n = 59). Overexpression of NCAPG indicates poor overall survivability in lung adenocarcinoma (LUAD) patients [hazard ratio (HR) = 1.6, confidence interval (CI) = 1.34-1.9, p = 9.9e-08] and those with a smoking history (HR = 1.44, CI = 1.11-1.87, p = 0.0062), but not significantly associated with lung squamous cell carcinoma (LUSC). miRNA hsa-let-7b-5p negatively correlates (R = -0.348) with NCAPG expression, with its down expression associated with poor survivability (HR = 0.71), while lncRNA TMPO-AS1 positively correlates (R = 0.575) with the NCAPG axis, with its overexpression associated with poor survivability (HR = 2.16).

Conclusion: Elevated levels of NCAPG and TMPO-AS1 in lung adenocarcinoma patients lead to aggressive growth and poor prognosis. miRNA hsa-let-7b-5p, a key miRNA, may inhibit these factors, potentially improving patient prognosis. Further research and clinical trials are needed to validate this targeted therapy.

Background: The energy spectrum is the main component of the Monte Carlo model of the electron beam. One possible method to obtain it is a backward reconstruction from the measured depth dose distribution, owing to solving the inverse first-degree Fredholm integral equation with appropriate regularisation. This study aimed to reconstruct and validate energy spectra for mobile intraoperative accelerators.

Materials and methods: The Geant4 package was used to simulate percentage depth dose (PDD) distributions. The micro-Diamond detector and the BeamScan water phantom were used to measure PDD. 160 PDDs were simulated for quasi-monoenergetic beams with energies from 0 to 20 MeV for a 10 cm diameter applicator. Using the simulated and measured PDDs, energy spectra were reconstructed for all available nominal energies by solving the inverse Fredholm equation. A single Gaussian peak was used as a reference solution, and the regularisation parameter λ was set to 0.05. Obtained spectra were used to simulate PDD for 5 and 6 cm applicators and compared with the measurements.

Results: Simulated and measured PDDs were compared using the gamma analysis method with 2% DD and 2 mm distance to agreement (DTA) criteria. Measured and simulated PDDs agree perfectly for the 4 MeV beam. For higher energies, the PDDs agree at all depths except for depths less than 2 mm.

Conclusion: The numerical solution of the inverse Fredholm equation with Tikhonov regularisation using simulated annealing optimisation is a reliable method to reconstruct the energy spectrum for electron beams produced by mobile intraoperative accelerators.