Conformal Intensity-modulated Radiotherapy Research Articles

Predictive model for acute radiation esophagitis in esophageal carcinoma based on prognostic nutritional index and systemic inflammatory index and its application.

Acute radiation esophagitis (ARE) is a common complication in patients with esophageal cancer undergoing radiotherapy. Therefore, it is important to construct an effective ARE risk-prediction model for clinical treatment. The present study performed a retrospective analysis of 225 patients with esophageal cancer who received radiotherapy at the First Affiliated Hospital of Anhui Medical University (Hefei, China) from January 2018 to December 2022. Univariate and logistic regression analyses were performed to screen patients with esophageal cancer after radiotherapy. The results revealed that 147 patients developed radiation esophagitis. Logistic regression analysis results demonstrated that the prognostic nutritional index [odds ratio (OR), 0.864; 95% confidence interval (CI), 0.809-0.924], neutrophil to lymphocyte ratio (OR, 1.795; 95% CI, 1.209-2.667) and platelet to lymphocyte ratio (OR, 1.011; 95% CI, 1.000-1.022) were independent predictors of ARE in patients receiving intensity-modulated conformal radiotherapy for esophagus cancer (P<0.05). A nomogram model for predicting the occurrence of ARE was established based on the three risk factors. The decision curve suggested a high net benefit value when the threshold probability was within 0.25-1.0. External verification confirmed the reproducibility and generalizability of the nomogram model. In general, the calibration curve of this model was close to the ideal curve and had excellent prediction accuracy. Therefore, it may be used as a new tool for early prediction of the ARE risk.

3D printed heterogeneous paediatric head and adult thorax phantoms for linear accelerator radiotherapy quality assurance: from fabrication to treatment delivery.

This study aims to design and fabricate a 3D printed heterogeneous paediatric head phantom and to customize a thorax phantom for radiotherapy dosimetry. &#xD;Approach: This study designed, fabricated, and tested 3D printed radiotherapy phantoms that can simulate soft tissue, lung, brain, and bone. Various polymers were considered in designing the phantoms. Polylactic acid+, nylon, and plaster were used in simulating different tissue equivalence. Dimensional accuracy, and CT number were investigated. The phantoms were subjected to a complete radiotherapy clinical workflow. Several treatment plans were delivered in both the head and the thorax phantom from a simple single 6 MV beam, parallel opposed beams, and five-field intensity modulated radiotherapy (IMRT) beams. Dose measurements using an ionization chamber and radiochromic films were compared with the calculated doses of the Varian Eclipse treatment planning system (TPS). &#xD;Main results: The fabricated heterogeneous phantoms represent paediatric human head and adult thorax based on its radiation attenuation and anatomy. The measured CT number ranges are within -786.23 ± 10.55, 0.98 ± 3.86, 129.51 ± 12.83, and 651.14 ± 47.76 HU for lung, water/brain, soft tissue, and bone, respectively. It has a good radiological imaging visual similarity relative to a real human head and thorax depicting soft tissue, lung, bone, and brain. The accumulated dose readings for both conformal radiotherapy and IMRT match with the TPS calculated dose within ±2% and ±4% for head and thorax phantom, respectively. The mean pass rate for all the plans delivered are above 90% for gamma analysis criterion of 3% / 3 mm.&#xD;Significance and conclusion: The fabricated heterogeneous paediatric head and thorax phantoms are useful in Linac end-to-end radiotherapy quality assurance based on its CT image and measured radiation dose. The manufacturing and dosimetry workflow of this study can be utilized by other institutions for dosimetry and trainings. &#xD.

Dosimetric Impact of Voluntary Deep Inspiration Breath Hold (DIBH) in Mediastinal Hodgkin Lymphomas: A Comparative Evaluation of Three Different Intensity Modulated Radiation Therapy (IMRT) Delivery Methods Using Voluntary DIBH and Free Breathing Techniques.

Hodgkin lymphomas are radiosensitive and curable tumors that often involve the mediastinum. However, the application of radiation therapy to the mediastinum is associated with late effects including cardiac and pulmonary toxicities and secondary cancers. The adoption of conformal IMRT and deep inspiration breath- hold (DIBH) can reduce the dose to healthy normal tissues (lungs, heart and breast). We compared the dosimetry of organs at risk (OARs) using different IMRT techniques for two breathing conditions, i.e., deep inspiration breath hold (DIBH) and free breathing. Twenty-three patients with early-stage mediastinal Hodgkin lymphomas were accrued in the prospective study. The patients were given treatment plans which utilized full arc volumetric modulated arc therapy (F-VMAT), Butterfly VMAT (B-VMAT), and fixed field IMRT (FF-IMRT) techniques for both DIBH and free breathing methods, respectively. All the plans were optimized to deliver 95% of the prescription dose which was 25.2 Gy to 95% of the PTV volume. The mean dose and standard error of the mean for each OAR, conformity index (CI), and homogeneity index (HI) for the target using the three planning techniques were calculated and compared using Student's t-test for parametric data and Wilcoxon signed-rank test for non-parametric data. The HI and CI of the target was not compromised using the DIBH technique for mediastinal lymphomas. The mean values of CI and HI for both DIBH and FB were comparable. The mean heart doses were reduced by 2.1 Gy, 2.54 Gy, and 2.38 Gy in DIBH compared to FB for the F-VMAT, B-VMAT, and IMRT techniques, respectively. There was a significant reduction in V5Gy, V10Gy, and V15Gy to the heart (p < 0.005) with DIBH. DIBH reduced the mean dose to the total lung by 1.19 Gy, 1.47 Gy, and 1.3 Gy, respectively. Among the 14 female patients, there was a reduction in the mean right breast dose with DIBH compared to FB (4.47 Gy vs. 3.63 Gy, p = 0.004). DIBH results in lower heart, lung, and breast doses than free breathing in mediastinal Hodgkin Lymphoma. Among the different IMRT techniques, FF-IMRT, B-VMAT, and F-VMAT showed similar PTV coverage, with similar conformity and homogeneity indices. However, the time taken for FF-IMRT was much longer than for the F-VMAT and B-VMAT techniques for both breathing methods. B-VMAT and F-VMAT emerged as the optimal planning techniques able to achieve the best target coverage and lower doses to the OARs, with less time required to deliver the prescribed dose.

Helical Tomotherapy and Melphalan As the Conditioning Regimen in Autologous Stem Cell Transplantation for Multiple Myeloma with Extramedullary Plasmacytoma: A Single Center Clinical Research

Background Multiple myeloma(MM) is the second hematologic malignancy. Extramedullary myeloma indicates a poorer prognosis and survival. High dose Melphalan is the most widely used conditioning regimen. Helical tomotherapy(TOMO) is one of the most advanced intensity-modulated conformal radiotherapy technologies. We applied the combination of TOMO and Melphalan as the conditioning regimen in MM patients, and analyzed its efficacy and safety. Methods Clinical data were collected and compared between TOMO combined with melphalan group and non-TOMO group. SPSS V.25.0 was used for statistical analysis. Results Two methods were not significant difference by statistics analysis. The complete response rate of 100d in non-TOMO group significantly decreased compared to 1 month after transplantation (P=0.001). The 1-year PFS rate in the TOMO group was 86%, while non-TOMO group was 91%. There was no myeloma related death in the two groups within one year. TOMO group showed earlier enter platelet count below 20x109/L (P=0.003) and granulocyte deficiency (P=0.000). In terms of platelet implantation time,TOMO group was superior in platelet implantation time (P=0.041). No atrial fibrillation, heart failure, hepatic small vein occlusion, or transplant related death occurred during the transplantation period. Conclusion: The combination of TOMO and reduced dose Melphalan conditioning regimen is clinically feasible in terms of safety and efficacy evaluation. This scheme could improve the long-term survival of MM patients with extramedullary plasmacytoma.

IMRT in the treatment of locally advanced or inoperable NSCLC in the pre-durvalumab era: clinical outcomes and pattern of relapses, experience from the Oscar Lambret Center.

Intensity-modulated conformal radiotherapy (IMRT) has become the technique of choice for the treatment of locally advanced or inoperable non-small cell lung cancer (NSCLC). Nevertheless, this technique presents dosimetric uncertainties, particularly in treating moving targets such as pulmonary neoplasms. Moreover, it theoretically increases the risk of isolated nodal failure (INF) due to reduced incidental irradiation. The objective of this study was to evaluate the efficacy and safety of IMRT in patients with inoperable NSCLC and to describe the pattern of relapses. Patients with locally advanced NSCLC treated with radiotherapy and chemotherapy between 2015 and 2018 at the Oscar Lambret Center were retrospectively included in the study. Overall and progression-free survival were estimated using the Kaplan-Meier method. The cumulative incidence of the different components of relapse was estimated using the Kalbfleisch and Prentice method. Prognostic factors for relapse/death were investigated using the Cox model. A comparison with literature data was performed using a one-sample log-rank test. Seventy patients were included, and 65 patients (93%) had stage III disease. All the patients received chemotherapy, most frequently with cisplatin and navelbine. The dose received was 66 Gy administered in 33 fractions. The median follow-up and survival were 49.1 and 39.1 months, respectively. A total of 35 deaths and 43 relapses, including 29 with metastatic components, were reported. The overall survival rates at 1 and 2 years were 80.2% (95% confidence interval 68.3%-88.0%) and 67.2% (95% confidence interval 54.2%-77.3%), respectively. Locoregional relapse was observed in 14 patients, including two INF, one of which was located in the lymph node area adjacent to the clinical target volume. Median relapse-free survival was 15.2 months. No variable was statistically associated with the risk of relapse/death in multivariate analysis. Seven patients (10%) experienced grade 3 or higher toxicity. The use of IMRT for locally advanced or inoperable NSCLC led to favorable long-term clinical outcomes. The rate of locoregional relapse, particularly isolated lymph node failure, was low and comparable with that of the three-dimensional radiotherapy series, as was the rate of early and late toxicities.

Uncertainty and influencing factors of the placement error of three-dimensional conformal intensity-modulated radiotherapy for thoracic tumors.

Radiation therapy is an important method for the treatment of chest tumors. This study discussed the placement error of three-dimensional (3D) conformal intensity-modulated radiotherapy in patients with different types of chest tumors and analyzed the relevant influencing factors. 100 patients with chest tumors diagnosed and treated in our hospital from March 2016 to March 2018 were randomly selected as research subjects, including 42 cases of esophageal cancer, 44 cases of breast cancer, and 14 cases of lung cancer. All patients underwent 3D conformal radiotherapy. The setup errors of patients with esophageal cancer, breast cancer, and lung cancer were detected after 3D conformal radiotherapy. Besides, the influencing factors of 3D conformal for thoracic tumors were analyzed by multiple linear regression analysis. After 3D conformal radiotherapy, the systematic errors of patients with esophageal cancer in X-axis, Y-axis, and Z-axis were -0.10, 1.26 and 0.07, respectively, while the random errors in X-axis, Y-axis, and Z-axis were 1.18, -1.14, and 0.97 respectively. The times for the absolute values of the positioning error with a range of ≤5 mm in X-axis, Y-axis, and Z-axis were 40 (95.24%), 2 (4.76%) and 36 (85.71%), while these with a range of >5 mm in X-axis, Y-axis, and Z-axis were 6 (14.29%), 41 (97.62%) and 1 (2.38%), respectively. For patients with breast cancer, the systematic errors and random errors in X-axis, Y-axis, and Z-axis are -0.19, 1.19, and 0.15, as well as 0.97, 0.02 and 1.29, respectively. The times for the absolute values of the positioning error with a range of ≤5 mm and >5 mm were 41 (93.18%), 3 (6.82%), and 36 (81.82%), as well as 8 (18.18%), 42 (95.45%) and 2 (4.55%), severally. For patients with lung cancer, the systematic errors and random errors in X-axis, Y-axis, and Z-axis were 0.14, 1.42, and 0.15, as well as 1.35, -0.23 and 1.12, respectively. The times for the absolute values of the positioning error with the range of ≤5 mm and >5 mm were 14 (93.33%), 1 (6.67%), and 11 (73.33%), as well as 4 (26.67%), 14 (93.33%) and 1 (6.67%) after 3D conformal radiotherapy. After multiple linear regression analyses, gender and lung volume were the influencing factors of Z-axis setup error, and the lesion location was the influence factor of Y-axis setup error (p<0.05). There are certain positioning errors in the X-axis, Y-axis, and Z-axis directions of thoracic tumors receiving 3D conformal radiotherapy. Gender, lung volume, and lesion location are all important factors that affect the placement error. The results of this study provide a certain reference for the positioning error of radiation therapy for thoracic tumors, which is conducive to improving the accuracy of radiotherapy and better protecting the surrounding tissues.

Treatment Outcome of Early-stage Laryngeal Carcinoma Treated with Radical Radiotherapy Using Different Techniques: A Retrospective Study

Aim: The aim was to evaluate the treatment outcomes and prognostic characteristics of patients with early-stage glottic laryngeal carcinoma who underwent radical radiotherapy (RT) with different techniques.Materials and Methods: Radiotherapy was applied using the 2D conventional technique, 3DCRT (three dimensional conformal radiotherapy and IMRT (intensity modulated radiation therapy). Clinical T stages were 12 (48%) for T1a, 5 (20%) for T1b and 8 (32%) for T2. Stage and anterior commissure involvement were analyzed as prognostic factors. Results: There were 12 (48%) patients with T1a, 5 (20%) patients with T1b and 8 (32%) patients with T2 cancer. 5 years of overall survival and diseases free survival for T1a, T1b, T2 were found to be 91%, 80%, 62% and 91%, 80%, 62% respectively. 5 year survival for patients without and with involvement of anterior commissure was 92% and 67% respectively. Hence, showing poor survival in patients with T2 lesion or T1 lesion with involvement of anterior commissure. Conclusion: In early-stage laryngeal carcinomas, radical RT is a function sparing and effective treatment modality with excellent survival rates, regardless of treatment techniques.

Cochlear sparing in LINAC-based radiosurgery for vestibular schwannoma: a dosimetric comparison of dynamic conformal arc, IMRT and VMAT treatment plans

BackgroundStereotactic radiosurgery (SRS) is the preferred treatment for vestibular schwannoma (VS) in patients with preserved hearing and tumour diameter < 3 cm. Emerging evidence suggests restricting cochlear dose could preserve hearing. This retrospective replanning study aims to compare dynamic conformal arc therapy (DCAT), intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans for superiority of cochlear dose sparing without compromising tumour coverage.MethodsEligibility criteria included sporadic VS, serviceable hearing and availability of CT and MRI for planning. The original gross tumour volume and brainstem OAR volume were retained; the cochlea was newly contoured on the planning CT scan (bone window). Each case was replanned using the three above techniques, prescribing 12 Gy to the 80% isodose line. No dose constraint was applied to the cochlea.ResultsEighteen patients were replanned. Mean tumour volume was 2.25 cc. Tumour coverage and tumour mean dose (DCAT: 14.2, IMRT: 14.6, VMAT: 14.5 Gy) were comparable. Paddick and RTOG conformity indices were better for DCAT (0.66 and 1.6) and VMAT (0.69 and 1.5) compared to IMRT (0.56 and 1.9). DCAT had superior gradient index (3.0) compared to VMAT (3.4) and IMRT (3.4). VMAT delivered the lowest mean brainstem maximum dose (8.3 Gy) and decreased the mean cochlear dose (3.4 Gy) by 2.3 and 2.1 Gy, and the mean cochlear maximum dose (3.6 Gy) by 2.4 and 2.5 Gy relative to DCAT and IMRT, respectively.ConclusionLINAC-based SRS treatment using VMAT can achieve better cochlear dose sparing than DCAT or IMRT while maintaining tumour coverage.

Hypofractionated reirradiation by conformal radiotherapy techniques in recurrent anaplastic astrocytoma and glioblastoma multiforme: An observational study at a Tertiary Care Center in North India

Aim and Objectives: The aims and objectives of the study were to assess the progression-free survival (PFS) and overall survival, local tumor control rate (response rate), effect on the quality of life, and treatment-related toxicities in all patients diagnosed with recurrent high-grade gliomas (HGGs). Methodology: The present study was conducted between September 2017 and July 2019 in the Department of Radiation Oncology, Sheri Kashmir Institute of Medical Sciences and included a total of 22 patients. The study included recurrent HGGs (Grade III/IV) Operated Cases of Grade III and Grade IV. Results: The majority of our patients were between the age group of 40–60 years (45.5%). There were 12 males (54.5%) and 10 females (45.5%). GBM was the most common diagnosis in 13 (59.1) patients and 9 (40.9%) were anaplastic astrocytoma. Sixteen patients were diagnosed as recurrent HGG radiologically. Sixteen (72.7%) patients achieved partial response and 6 (27.3%) achieved stable disease. The median PFS was 2.8 months and the median overall survival was 4.2 months. Conclusion: Reirradiation is one of the treatment options for recurrent HGGs and conformal intensity-modulated radiotherapy can be effective treatment modality for recurrent high-grade brain tumors with only mild side effects. Although survival is better in patients with good performance status and young age.

Impact of Lung and Heart Radiation Dose during Preoperative Chemoradiation on Overall Survival (OS) in Esophageal Cancer (EC) – Secondary Analysis of CALGB 80803 (Alliance)

<h3>Purpose/Objective(s)</h3> In CALGB 80803, patients with locally advanced EC received PET-directed neoadjuvant therapy consisting of induction chemotherapy followed by chemoradiation and then surgical resection. Historically, radiotherapy has been delivered using techniques with limited ability to minimize doses to the heart and lungs, potentially leading to increased risk of peri-operative and late cardiopulmonary toxicities with significant morbidity and mortality. We evaluated the relationship between OS and radiation dose to the heart and lungs, and the impact of intensity-modulated radiation therapy (IMRT) and adherence to protocol-specified dose constraints in CALGB 80803. <h3>Materials/Methods</h3> Protocol-specified dose constraints were based on standard of care guidelines: total lung V_{10 Gy} ≤ 40%, V_{20 Gy} ≤ 20%, V_{30 Gy} ≤ 15%, V_{40 Gy} ≤ 10%; heart V_{30 Gy} ≤ 30%. Optimal dose cutpoints for each volumetric constraint were calculated that best differentiated OS. Each cutpoint was dichotomized and the Kaplan-Meier method was used to evaluate its impact on OS. The significance threshold was <i>p</i><0.05 and a Holm multiple comparisons correction was applied. <h3>Results</h3> There were 226 patients (n) included in the analysis, 60.3% were treated with IMRT. Rates of adherence were high for each of the protocol-specified dose constraints: 74.8%, 84.1%, 98.7%, 99.1%, and 73.0% for total lung V_{10 Gy}, V_{20 Gy}, V_{30 Gy}, V_{40 Gy}, and heart V_{30 Gy}, respectively. See the table for calculated dose cutpoints for each dosimetric variable as well as treatment and survival data. For heart V_{30 Gy}, 90.6% and 68.2% with V₃₀ Gy > 21% received three-dimensional conformal radiation therapy (3D-CRT) vs IMRT, respectively, while 9.4% and 31.8% with V_{30 Gy} > 21% received 3D-CRT vs IMRT, respectively (<i>p</i> < 0.001). Mean heart V_{30 Gy} was significantly lower in the IMRT vs 3D-CRT group (24.7% vs 35.5%; <i>p</i> < 0.001). On univariable Cox regression, lung V_{10 Gy} > 41% (hazard ratio [HR]: 1.87; <i>p</i> = 0.002) and heart V_{30 Gy} > 21% (HR: 1.77; <i>p</i> = 0.017) were significant poor prognostic factors for OS. <h3>Conclusion</h3> The majority of patients on CALGB 80803 were treated with IMRT plans that met the protocol-specified dose constraints for total lung and heart_. Minimizing volume of low dose to the lungs (V_{10 Gy}) was associated with a significant survival benefit, as was a lower heart V_{30 Gy}. Total lung V_{10 Gy} ≤ 41% and heart V_{30 Gy} ≤ 21%, and the use of IMRT over 3D-CRT, should be considered when designing radiation plans for EC patients. <b>Support:</b> U10CA180821, U10CA180882; https://acknowledgments.alliancefound.org. <b>ClinicalTrials.gov ID:</b> NCT01333033

Accelerated Partial Breast Irradiation (APBI) Using Five Daily Fractions: A Prospective, Phase II, Multi-Center Trial of Cosmetic Outcomes and Toxicity: Final Results

<h3>Purpose/Objective(s)</h3> To report final results of a clinical trial of APBI using intensity modulated radiotherapy (IMRT) to deliver 27 Gy in 5 daily fractions following breast conserving surgery (BCS) prospectively designed to assess the efficacy and cosmetic outcomes of a 1-week, APBI regimen among women with early breast cancer. <h3>Materials/Methods</h3> Women ≥ 50 years, with lymph node-negative, ER positive, HER-2 negative breast cancer or ductal carcinoma in situ (DCIS), ≤ 3cm diameter, following BCS with margins ≥ 2mm, and excellent or good baseline cosmesis received 27 Gy in 5 daily fractions to the seroma plus 1 cm CTV and 0.7 cm PTV margins. Clinical photographs, patient and provider cosmetic scores, breast fibrosis, telangiectasia and pain were collected prospectively, prior to RT and at 6 weeks, 1 and 2 years after RT. The primary endpoint was the proportion of women who retained Excellent or Good cosmesis at 2 years using the EORTC Cosmetic Rating System. Cosmetic failure was deterioration from Excellent or Good to Fair or Poor. A panel of 5 radiation oncologists independently assessed the cosmetic photographs. Secondary endpoints were rates and grades of breast fibrosis, telangiectasia, breast pain, ipsilateral breast tumor recurrence (IBRT), overall (OS), breast cancer-specific survival (BCSS) and subsequent mastectomy. Efficacy outcomes were assessed at clinic visits and by review of charts. ClinicalTrials.gov registration: NCT02681107. <h3>Results</h3> A total of 298 patients were treated between April 25, 2016, and October 31, 2019. At a median follow up of 48 months, the 4-year OS was 98.5% (95% CI 96.1% - 99.5%) and BCSS was 99.7% (95% CI 97.6% - 99.9%). The 4-year IBRT rate was 3.3% (95% CI 1.1% - 6.4%). There were 10 contralateral breast events for a 4-year rate of 3.9% (95% CI 2.2% - 6.9%). There were 10 ipsilateral and 6 contralateral mastectomies. Two patients died of unrelated causes prior to 2 years; 79 patients declined in-clinic attendance due to COVID or competing comorbidities and 217 women had 2-year cosmetic photographs and clinical assessments performed. Consensus of the photo-panel cosmesis at baseline was: Excellent: n=116 (53%), Good: n=102 (47%), Fair: n=1 (0.5%) and Poor: n=0. Consensus overall cosmesis at 2 years was: Excellent: n=141 (65%), Good: n=78 (35%), Fair: n=0 and Poor: n=0. Most patients had either improved (n=168; 77%) or no change (n=43; 20%) in cosmesis at 2-years. No patient had cosmetic failure but 6 (3%) had a change from Excellent to Good at 2 years. Most patients reported either no (79%) or mild (21%) pain, with no moderate or severe pain. Two patients (0.9%) had grade 2 fibrosis and 5 patients (2%) had visible telangiectasia that did not detract from overall cosmesis. <h3>Conclusion</h3> APBI using 27 Gy in 5 fractions using a conformal IMRT technique, achieved excellent 2-year cosmesis with minimal toxicity. The IBRT risk was comparable to the contralateral new breast cancer risk and to local recurrence rates of recently published early breast cancer trials.

Construction of a predictive model for radiation proctitis after radiotherapy for female pelvic tumors based on machine learning.

Radiation therapy is a main method for female pelvic malignancies, which can cause some adverse reactions, such as radiation proctitis (RP). The incidence of RP is highly positively correlated with radiation dose. There is an urgent need for a scientific method to accurately predict the occurrence of RP to help doctors make clinical decisions. In this study, based on the clinical data of female pelvic tumor patients and dosimetric parameters of radiotherapy, the random forest method was used to screen the hub features related to the occurrence of RP, and then a machine learning algorithm was used to construct a risk prediction model for the occurrence of RP, in order to provide technical support and theoretical basis for the prediction and prevention of RP. A total of 100 female patients with pelvic tumors, who received static three-dimensional conformal intensity-modulated radiation therapy in the Department of Radiation Oncology of the Affiliated Hospital of Xiangnan University from January 2019 to December 2020, were retrospectively collected, and their clinically relevant data and radiotherapy planning system data were collected. During radiotherapy and 18 months after radiotherapy, 35 cases developed RP (RP group), and the remaining 65 cases had no RP (non-RP group). The clinical and dosimetric characteristics of patients were ranked by the importance of random forest algorithm, and the independent prognostic characteristics associated with the occurrence of RP were selected for machine learning modeling. A total of 6 machine learning algorithms including support vector machines, random forests, logistic regression, lightweight gradient boosting machines, Gaussian naïve Bayes, and adaptive enhancement were used to build models. The performance of the model was evaluated by the area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F1 score. Finally, the random forest model was determined as the prediction model, and the calibration curve and decision curve of the prediction model were drawn to evaluate the accuracy and clinical benefit of the model. The parameters for random forest prediction model in the training set were as follow: AUC, 1.000, accuracy, 0.988, sensitivity, 1.000, specificity, 1.000, positive predictive value, 1.000, negative predictive value, 0.981, and F1 score, 1.000. In validation set, AUC was 0.713, accuracy was 0.640, sensitivity was 0.618, specificity was 0.822, positive predictive value was 0.500, negative predictive value was 0.656, and F1 score was 0.440. Random forest showed high predictive performance. Moreover, the Brief of the calibration curve for the prediction model was 0.178, the prediction accuracy was high, and the decision curve showed that the prediction model could benefit clinically. Based on the clinical and dosimetric parameters for the female pelvic tumor patients, the prediction model of radiation proctitis constructed by random forest algorithm has high predictive ability and strong clinical usability.

The Effect on Quality of Life after Three-Dimensional Intensity-Modulated Radiation Therapy in Patients with Low-Grade Glioma.

Objective To investigate the effect of three-dimensional intensity-modulated radiation therapy (IMRT) that accurately target delineation on quality of life (Qol) in patients with low-grade gliomas. Methods From February 2015 to December 2019, 100 patients with low-grade gliomas were randomly divided into three-dimensional conformal radiotherapy control group (n = 50) and three-dimensional IMRT research group (n = 50). The scores of the Mini-Cog Assessment (Mini-Cog) and Montreal Cognitive Assessment Scale (MoCA), the self-care ability score (BI), and the effect of symptom improvement and the quality of life SF-36 score were compared between the two groups. Results After radiotherapy, the self-care ability of patients in the two groups was significantly improved, and the improvement of study group was better than that of the control group (P < 0.05). The Mini-Cog and MOCA scores in the study group were significantly higher than those in the control group (P < 0.05). In addition, the symptom improvement effect and quality of life of the patients in the study group were also significantly better than those in the control group (P < 0.05). The scores of SDS and SAS of patients who underwent three-dimensional conformal IMRT were significantly lower than those of the control group. There was no significant difference in mortality between the two groups. Conclusion Three-dimensional conformal intensity-modulated radiation therapy can delineate the target volume more accurately, regulate the intensity of radiation, and improve the symptoms and quality of life of patients with low-grade gliomas.

Research Value of Intensity Modulated Radiation Therapy in Alleviating Parotid Gland Function Injury in Patients with Stage N0 Nasopharyngeal Carcinoma from Physical and Dosimetric Aspects.

Objective To study the feasibility of intensity modulated radiation therapy (IMRT) for stage N0 nasopharyngeal carcinoma (NPC) and its parotid gland (PG) function preservation from physical and dosimetric aspects. Methods All the clinical data of 77 patients with pathologically confirmed T1-4N0M0 NPC who received radiotherapy between July 2017 and October 2019 in the Radiotherapy Center of Taizhou Hospital of Zhejiang Province affiliated to Wenzhou Medical University were analyzed retrospectively. Three-dimensional conformal radiotherapy (3D-CRT) and IMRT were used in 35 and 42 cases, respectively. The treatment efficiency and the dosimetry differences of the PG in the intensity modulation plan were compared between groups. Quantitative monitoring of 99mTc radionuclide imaging of PG was performed before, at the end of, and 3, 6, and 12 months after radiotherapy. The degree of PG function injury and xerostomia was compared between groups at the end of radiotherapy and 12 months later. Results Higher minimal, maximal, and average irradiation doses of PG were determined in 3D-CRT-treated patients compared with IMRT-treated cases (P < 0.05). Compared with before radiotherapy, the PG uptake index (UI) and excretion index (EI) of both cohorts of patients decreased to varying degrees at the end of radiotherapy, with PG function injury and xerostomia symptoms observed in all cases but with no obvious difference between groups (P > 0.05). To a certain extent, the PG function recovered and the xerostomia symptoms relieved in both groups 12 months after radiotherapy, with better improvements in IMRT group versus 3D-CRT group. Conclusion IMRT has similar short-term efficacy to 3D-CRT in treating patients with stage N0 NPC, but it can effectively reduce the dose of PG radiotherapy and protect the PG function on the premise of ensuring sufficient tumor coverage and dose, showing certain dosimetry advantages.

A novel predictor for the use of concurrent chemotherapy in early-stage cervical cancer with intermediate-risk factors.

e17521 Background: For early-stage cervical cancer patients experiencing radical surgery, postoperative radiotherapy was recommended for patients with a combination of intermediate-risk factors. However, there was no consensus on whether to administer concurrent chemotherapy. The aim of the study was to confirm the clinical value of the controlling nutritional status (COUNT) score in guiding the use of concurrent chemotherapy in patients with early-stage cervical cancers during postoperative radiotherapy. Methods: A total of 945 patients with FIGO stage IB-IIA (2009) cervical cancer were retrospectively analyzed in the study from 2009 to 2018. There were 503 patents receiving concurrent chemoradiotherapy, while another 442 patents undergone radiotherapy lonely. Radiotherapy was performed by conformal radiotherapy or intensity-modulated radiotherapy. The concurrent chemotherapy regimen included either cisplatin or paclitaxel. Pre-treatment CONUT score were calculated within 1 weeks before curative resection. Low CONUT group and high CONUT group were defined based on the cutoff value of CONUT score which was determined by the receiver operating characteristic analysis. Kaplan-Meier survival analysis was performed to compare disease-free survival (DFS) and cancer-specific survival (CSS) rates between different group. A Cox proportional hazards regression test was used to conduct multivariate analyses of DFS, local recurrence-free survival and distant metastasis-free survival (DMFS). Results: The median follow-up was 54.6 months (range: 4.8-147.5 months). The optimal cutoff value of CONUT was 3 in the study. For the patients included in the high CONUT group (≥3), the addition of concurrent chemotherapy significantly improved treatment outcomes, and had better 5-year DFS (90.37% vs 70.69%, P &lt; 0.001) and CSS (95.02% vs 78.74%, P = 0.005) than those without it. Meanwhile, the patients with concurrent chemotherapy had less rate of distant metastasis (6.5% vs 28.1%, P &lt; 0.001). For the patients included in low CONUT group (&lt; 3), there was no difference in prognosis between patients receiving concurrent chemotherapy and not receiving. In the high CONUT group, the multivariate analysis showed that concurrent chemotherapy was detected to be a factor significantly associated with DFS (HR 3.077; 95% CI: 1.295-6.679, P = 0.011) and DMFS (HR 3.435; 95% CI: 1.506-7.014, P = 0.006). Conclusions: Pre-treatment CONUT score may be a predictive factor for the use of concurrent chemotherapy in early-stage cervical cancer patients with intermediate-risk factors during postoperative radiotherapy, and it can be helpful to determine the adjuvant treatment scheme.

Secondary Malignancy Risk Following Proton vs. X-ray Radiotherapy of Thymic Epithelial Tumors: A Comparative Modeling Study of Thoracic Organ-Specific Cancer Risk.

Simple SummaryProton beam radiotherapy (PBT) offers the possibility to significantly reduce dose to surrounding organs at risk due to their physical advantages compared to X-ray based techniques. The aim of this analysis was to demonstrate whether PBT reduces secondary malignancy risks in patients with thymic malignancies compared to 3D conformal and intensity-modulated radiotherapy with photons. By using two different mechanistic calculation models we could demonstrate significant reductions of secondary malignancy risks with the use of PBT for all independent thoracic organs analyzed with the exception of the thyroid gland. This technology-driven improvement might translate into clinically relevant benefits for patients with thymic malignancies.Background: Proton beam radiotherapy (PBT) offers physical dose advantages that might reduce the risk for secondary malignancies (SM). The aim of the current study is to calculate the risk for SM after X-ray-based 3D conformal (3DCRT) radiotherapy, intensity-modulated radiotherapy (IMRT), and active pencil beam scanned proton therapy (PBS) in patients treated for thymic malignancies. Methods: Comparative treatment plans for each of the different treatment modalities were generated for 17 patients. The risk for radiation-induced SM was estimated using two distinct prediction models—the Dasu and the Schneider model. Results: The total and fatal SM risks estimated using the Dasu model demonstrated significant reductions with the use of PBS relative to both 3DCRT and IMRT for all independent thoracic organs analyzed with the exception of the thyroid gland (p ≤ 0.001). SM rates per 10,000 patients per year per Gy evaluated using the Schneider model also resulted in significant reductions with the use of PBS relative to 3DCRT and IMRT for the lungs, breasts, and esophagus (p ≤ 0.001). Conclusions: PBS achieved superior sparing of relevant OARs compared to 3DCRT and IMRT, leading to a lower risk for radiation-induced SM. PBS should therefore be considered in patients diagnosed with thymic malignancies, particularly young female patients.

Research Progress of Radiotherapy for Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a common head and neck malignant tumor. Radiotherapy can effectively improve the tumor control rate because of its sensitivity to radiation. With the continuous update of radiotherapy technology, on the basis of conventional fractionated radiotherapy, unconventional fractionated radiotherapy, 3D conformal radiotherapy (3DCRT), intensity modulated conformal radiotherapy (IMRT), volume arc intensity modulated radiotherapy (VMAT) and other methods have been developed. In this paper, the research progress of radiotherapy for nasopharyngeal carcinoma was briefly reviewed.

Impact of different treatment plans on EQD2 for intracavitary brachytherapy of cervical cancer

BackgroundCancer is one of the leading causes of death worldwide. According to GLOBOCAN estimates, there were 341,831 deaths from cervical cancer in 185 countries in 2020. The aim of this study was to compare equieffective dose (EQD2) at 2 Gy per fraction by using dose volume histograms (DVHs) derived from external beam radiotherapy (EBRT) and high-dose rate brachytherapy (HDR-BRT) treatment plans used in cervical cancer radiotherapy.MethodsFifteen patients with stage IIB-IIIB cervical cancer were included in this retrospective study. Treatment with three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) was planned for all patients in 28 fractions, with a total of 50.4 Gy to be delivered to the whole pelvic region. After EBRT, manual optimization (MO) or inverse optimization (IO) HDR-BRT plans were created in 4 fractions with a total of 28 Gy. The plans obtained were grouped as IMRT + IO, IMRT + MO, 3DCRT + IO, and 3DCRT + MO by calculating EQD2s among these plans. D90, D95, and D98 values were compared in all plans for CTVHR total EQD2. In addition, EQD2 values ​for critical organs at risk (OARs) such as rectum, bladder, small intestine, and sigmoid were compared in all plans for volumes of 2 cm3, 1 cm3, and 0.1 cm3, respectively.ResultsThere was no significant difference between the treatment groups in terms of CTVHR D90 and CTVIR D90 values; However, CTVHR D95 (p = 0.000) and CTVHR D98 (p = 0.000) values ​were found to be better in IMRT + IO technique. The IMRT + IO technique provided better protection for 2 cm3, 1 cm3, and 0.1 cm3 volumes of OARs compared to other techniques.ConclusionsConsidering all parameters such as CTVHR, CTVIR, rectum, bladder, small intestine, and sigmoid, combination of IMRT + IO treatment option was found to be significantly superior in total EQD2 calculations compared to other plans.

Post-operative radiation therapy for non-small cell lung cancer: A comparison of radiation therapy techniques

ObjectivesPost-operative radiation therapy (PORT) in locally advanced non-small cell lung cancer (LA-NSCLC) has historically been associated with toxicity. Conformal techniques like intensity modulated radiation therapy (IMRT) have the potential to reduce acute and long-term toxicity from radiation therapy. Among patients receiving PORT for LA-NSCLC, we identified factors associated with receipt of IMRT and evaluated the association between IMRT and toxicity. MethodsWe queried the Surveillance, Epidemiology, and End Results (SEER)-Medicare database between January 1, 2006 to December 31, 2014 to identify patients diagnosed with Stage II or III NSCLC and who received upfront surgery and subsequent PORT. Baseline differences between patients receiving 3-dimentional conformal radiation therapy (3D-CRT) and IMRT were assessed using the chi-squared test for proportions and the t-test for means. Multivariable logistic regression was used to identify predictors of receipt of IMRT and pulmonary, esophageal, and cardiac toxicity. Propensity-score matching was employed to reduce the effect of known confounders. ResultsA total of 620 patients met the inclusion criteria, among whom 441 (71.2%) received 3D-CRT and 179 (28.8%) received IMRT. The mean age of the cohort was 73.9 years and 54.7% were male. The proportion of patients receiving IMRT increased from 6.2% in 2006 to 41.4% in 2014 (P < 0.001). IMRT was not associated with decreased pulmonary (OR 0.89; 95% CI, 0.62–1.29), esophageal (OR 1.09; 95% CI, 0.0.75–1.58), or cardiac toxicity (OR 1.02; 95% CI, 0.69–1.51). These findings held on propensity-score matching. Clinical risk factors including comorbidity and prior treatment history were associated with treatment toxicity. ConclusionIn a cohort of elderly patients, the use of IMRT in the setting of PORT for LA-NSCLC was not associated with a difference in toxicity compared to 3D-CRT. This finding suggests that outcomes from PORT may be independent of radiotherapy treatment technique.

Stereotactic Versus Conventional Radiation Therapy for Patients With Pancreatic Cancer in the Modern Era

PurposePatients with pancreatic cancer often receive radiation therapy before undergoing surgical resection. We compared the clinical outcomes differences between stereotactic body radiation therapy (SBRT) and 3-dimensional (3D)/intensity-modulated radiation therapy (IMRT). Methods and MaterialsWe retrospectively collected data from the University of Texas MD Anderson Cancer Center. Patients with borderline resectable/potentially resectable or locally advanced pancreatic cancer receiving neoadjuvant SBRT (median, 36.0 Gy/5fx), 3D conformal radiation (median, 50.4 Gy/28 fx) or IMRT (median, 50.4 Gy/28 fx) were included. Overall survival (OS) and progression-free survival were analyzed using Cox regression. ResultsIn total, 104 patients were included in our study. Fifty-seven patients (54.8%) were treated with SBRT, and 47 patients (45.2%) were treated with 3D/IMRT. Patients in the SBRT group were slightly older (median age: 70.3 vs 62.7 in the 3D/IMRT group). Both groups had similar proportions of patients with locally advanced pancreatic cancer (SBRT: 30, 52.6%; 3D/IMRT: 24, 51.1%). All patients were treated with chemotherapy. Patients in the SBRT group underwent more surgical resection compared with the 3D/IMRT group (38.6% vs 23.4%, respectively). At a median follow-up of 22 months, a total of 60 patients (57.7%) died: 25 (25/57, 43.9%) in the SBRT group, and 35 (35/47, 74.5%) in the 3D/IMRT group. Median OS was slightly higher in the SBRT group (29.6 months vs 24.1 months in the 3D/IMRT group). On multivariable Cox regression, the choice of radiation therapy technique was not associated with differences in OS (adjusted hazard ratios [aHR] = 0.5; 95% confidence interval [CI], 0.2%-1.3%, P = .18). Moreover, patients that underwent surgical resection had better OS (aHR = 0.3, 95% CI, 0.1%-0.8%, P = .01). Furthermore, progression-free survival was also similar between patients treated with SBRT and those treated with 3D/IMRT (aHR = 0.9, 95% CI, 0.5%-1.8%, P = .81) ConclusionsSBRT was associated with similar clinical outcomes compared with conventional radiation techniques, despite being delivered over a shorter period of time which would spare patients prolonged treatment burden. Future prospective data are still needed to better assess the role of SBRT in patients with pancreatic cancer.