Search

Byline: Avinav. Bharati, Satyajeet. Rath, Rohini. Khurana, Madhup. Rastogi, Susama. Mandal, Ajeet. Gandhi, Rahat. Hadi, Anoop. Srivastava, Surendra. Mishra Introduction: The purpose of this study was to compare the dosimetric [...]

Byline: Avinav. Bharati, Susama. Mandal, Arun. Gupta, Amlesh. Seth, Raju. Sharma, Ashu. Bhalla, Chandan. Das, S. Chatterjee, Pratik. Kumar Aim: This study aims to develop a method using dual-energy computed [...]

Purpose: Development and validation of a simple and convenient computational program in MATLAB environment for estimating the tumor control probability (TCP) and the normal tissue complication probability (NTCP), as a decision support system for routine plan evaluation.Materials and Methods: We developed an in-house software using MATLAB 2016b (Mathworks) for estimating TCP and NTCP named as RBMODELV1. The program contains Niemierko free equivalent uniform dose (EUD) program code provided in authors research article. For rest of radiobiological (RB) models in the software separate coding is performed. The program accepts cumulative dose-volume histogram file in (.txt) format containing two columns dose and volume. A set of two RB parameters were prepared, default and user-dependent in excel sheet named as RBDATA. We cross-validated results of RBMODELV1 software with BioSuite software for Poisson's TCP model and Lyman-Kutcher-Burman (LKB) model. A set of total 20 patient's data of head and neck site took under study and respective TCP and NTCP calculated by all the RB models and compared.Results: This is the first study in which we tried to establish correlation between the mean doses (EUD) received by parallel structure (parotid gland and oral cavity) and predicted percentage of NTCP values. It is found that mean dose in the range of 35-40 Gy for parotid gland can result in more than 50% NTCP predicted by all four RB models. Similarly oral cavity receiving mean dose in the range of 53-58 Gy can results in more than 35% NTCP predicted by all the four models. There is <3% variation observed between TCP calculated by BioSuite and RBMODELV1 software and <4% variation observed between predicted NTCP for parotid gland and oral cavity OAR from LKB model by both the software.Conclusion: We created simple software RBMODELV1 which can be used as a research tool as well as decision support system. [ABSTRACT FROM AUTHOR]

Introduction: Dosimetric advantages of volumetric-modulated arc therapy (VMAT) over three-dimensional conformal radiotherapy (3D-CRT) are not established in a head-on comparison of a uniform group of locally advanced carcinoma of the cervix (LACC). Therefore, we conducted a dosimetric comparison of these two techniques in LACC patients. Materials and methods: Computed tomography (CT) data of histologically proven de novo LACC, including Stage IIB–IIIB and earlier stages deemed inoperable, were included in this prospective observational dosimetric study. Planning was initially done by 3D-CRT technique (dose of 45–50·4 Gy @ 1·8–2 Gy/# was used in the actual treatment), followed by VMAT planning and appropriate dosimetric comparisons were done in 39 cases. Results: For planning target volume coverage, D95, D98 and D100 (p < 0·0001 for all parameters) and V95 and V100 (p = 0·002 and <0·0001, respectively) were significantly improved with VMAT. The conformity index (CI) was significantly better with VMAT (p = 0·03), while 3D-CRT had a significantly better homogeneity index (HI)(p = 0·003). Dose to the urinary bladder was significantly reduced with VMAT compared to 3D-CRT for V20–V50, except V10. The doses to the rectum and abdominal cavity were significantly reduced with VMAT compared to 3D-CRT plans for all parameters (V10–V50). The number of organs at risks (OARs) for which constraints were met was higher with VMAT plans than with 3D-CRT plans, with at least four out of the five OARs protected in 46·1 versus 5·1% and all constraints achieved in 15·4% versus none. Conclusion: We conclude that in dosimetric terms, VMAT is superior to 3D-CRT for LACC. [ABSTRACT FROM AUTHOR]

Introduction: We aimed to dosimetrically compare three-dimensional conformal radiotherapy (3D-CRT) and volumetric modulated arc therapy (VMAT) in terms of planning target volume (PTV) coverage, organ at risk (OAR) sparing, and conformity index (CI). Material and Methods: Planning data of 26 high grade glioma (HGG) patients were used. Prescribed dose for 3D-CRT was 46Gy in 23 fractions to low-risk PTV (LR-PTV) and 14 Gy in 7 fractions to high-risk PTV (HR-PTV). VMAT plans were conducted using 46 Gy in 30 fractions to LR-PTV and 60 Gy in 30 fractions to HR-PTV. Results: Tumor locations were frontal, parietal, temporal, and multi-lobed in 27%, 15%, 23%, and 35% of cases, respectively. Histology was glioblastoma multiform in 89% of patients. Mean values of PTV D95 (dose received by 95% volume) in 3D-CRT and VMAT were 96.6% and 98.8% for the LR-PTV and 97.3% and 99% for HR-PTV (P<0.001), respectively. Mean values of CI in 3D-CRT were 0.96 and 0.97 for LRPTV and HR-PTV and 0.98 and 0.99 for LR-PTV and HR-PTV of VMAT (both P<0.001), respectively. Mean Dmax of right optic nerve (maximum point dose received by the organ) for 3D-CRT and VMAT were 31.59 and 25.57Gy (P=0.02). Mean Dmax for left optic nerve and optic chiasm were 28.81 and 22.14 Gy (P=0.019) and 42.24 and 37.12 Gy (P=0.055) respectively for 3D-CRT versus VMAT. Doses to other OARs were not statistically different between 3D-CRT and VMAT. Conclusion: VMAT achieved better coverage of the PTV and delivered fewer doses to bilateral optic nerve and chiasm. [ABSTRACT FROM AUTHOR]

Purpose: To analyse the safety and efficacy of neoadjuvant chemoradiation (NACRT) with dose-escalated image-guided intensity modulated radiation therapy (IG-IMRT) in locally advanced (T3/4; T1-4N1-2) rectal cancers (LARCs). Materials and methods: Twenty patients with the diagnosis of LARC were recruited in this prospective interventional single-arm study treated by IG-IMRT with 45 Gray (Gy) in 25 fractions to elective nodal volumes and 55 Gy in 25 fractions to the gross primary and nodal disease with concurrent capecitabine 825 mg/m2 twice daily on radiotherapy days. Patients underwent total mesorectal excision 6-8 weeks post completion of NACRT followed by adjuvant chemotherapy (Capecitabine and oxaliplatin every 3 weekly for 6-8 cycles). Primary end point was acute toxicity assessment and secondary end points were pathological complete response (pCR) and loco-regional control (LRC). Results: Clinical T stage was T3:T4 in 19:1 and clinical N0:N1: N2 in 2:7:11 patients, respectively. With a median follow up of 21.2 months (13.8-25.6 months), 18 of 20 (90%) patients received the full course of treatment. Tumour and nodal downstaging was achieved in 78% and 84% of patients, respectively. pCR and overall complete response (defined as pCR and near CR) was achieved in 22.2% and 44.4% of patients, respectively. 2 (10%) patients completed NACRT, and achieved complete clinical response but refused surgery. Adjuvant chemotherapy course was completed by 17/18 (94.5%) patients. Grade 3 toxicities were observed in 2 (10%) patients during NACRT. All patients were disease-free at the time of the last follow up. Conclusion: Dose-escalation of NACRT therapy with IG-IMRT in LARC patients offers decent rates of pCR and overall response with excellent LRC and acceptable toxicities. [ABSTRACT FROM AUTHOR]

Introduction: The programmed death receptor ligand 1 (PD-L1) is a cell-surface glycoprotein expressed in tumour cells (TCs) and is also upregulated in tumour infiltrating lymphocytes. The effect of PD-L1 expression on TCs and tumour-infiltrating lymphocytes (TILs) on acute radiation toxicity and response in oropharyngeal squamous cell carcinoma treated with concurrent chemoradiotherapy is less known., Material and Methods: Squamous cell carcinoma of oropharynx with stage II-IVA (AJCC 8 th ) were recruited in this prospective observational study. Definitive radiation therapy (RT) of 70 Gray in 35 fractions at 2 Gray per fraction, 5 fractions a week in 2 phases was delivered with concurrent chemotherapy (cisplatin 40 mg/m 2 weekly). Patients were assessed weekly for acute toxicities with Radiation Therapy Oncology Group criteria. Response assessment was done at 3 months post RT according to World Health Organization response assessment criteria. The programmed death receptor ligand 1 expression in TCs and TILs was correlated with acute toxicity and survival., Results: Of 51 patients, 20 (39.2%) had PD-L1 expression in TCs and 18 (35.3%) in TILs. Patients with PD-L1 expression in TCs had fewer grade ≥ 3 oral mucositis (25% vs. 58%; p = 0.02) and grade ≥ 3 dysphagia (25% vs. 55%; p = 0.046). The programmed death receptor ligand 1-tumour infiltrating lymphocytes positives had lower ≥ 3 grade oral mucositis (22% vs. 58%; p = 0.02) and ≥ 3 grade dysphagia (17% vs. 58%; p = 0.007). Two-year overall and progression-free survival rate for the PD-L1-tumour-positive vs. PD-L1-tumour-negative group was not different ( p > 0.5)., Conclusions: Positive PD-L1 expression is associated with fewer acute radiation toxicities, and this could be used as a potential biomarker., Competing Interests: The authors declare no conflict of interest., (Copyright © 2022 Termedia.)