Automated VMAT planning for postoperative adjuvant treatment of advanced gastric cancer.
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ABSTRACT:
SUBMITTER: Sharfo AWM
PROVIDER: S-EPMC5913894 | biostudies-other | 2018 Apr
REPOSITORIES: biostudies-other
Publications
Automated VMAT planning for postoperative adjuvant treatment of advanced gastric cancer.
Sharfo Abdul Wahab M AWM Stieler Florian F Kupfer Oskar O Heijmen Ben J M BJM Dirkx Maarten L P MLP Breedveld Sebastiaan S Wenz Frederik F Lohr Frank F Boda-Heggemann Judit J Buergy Daniel D
Radiation oncology (London, England) 20180423 1
<h4>Background</h4>Postoperative/adjuvant radiotherapy of advanced gastric cancer involves a large planning target volume (PTV) with multi-concave shapes which presents a challenge for volumetric modulated arc therapy (VMAT) planning. This study investigates the advantages of automated VMAT planning for this site compared to manual VMAT planning by expert planners.<h4>Methods</h4>For 20 gastric cancer patients in the postoperative/adjuvant setting, dual-arc VMAT plans were generated using fully ...[more]
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Project description:BackgroundNeoadjuvant (chemo) radiotherapy is used as a standard treatment for locally advanced rectal cancer (LARC), but there is no general consensus on either the efficacy of postoperative adjuvant chemotherapy in patients with LARC after neoadjuvant treatment and surgery, or whether the addition of oxaliplatin to adjuvant chemotherapy provides survival benefits.MethodsWe performed a meta-analysis of data from the PubMed and Embase databases. We included patients with LARC who received neoadjuvant (chemo) radiotherapy and curative surgery. Overall survival (OS), disease-free survival (DFS), toxicity, and compliance were analyzed in the oxaliplatin/fluorouracil- (OX/FU-) based group compared with the FU-based group, and in the chemotherapy group compared with the observation group.ResultsTwenty studies were included in the analysis. Our results indicated that adjuvant chemotherapy prolonged OS (hazard ratio [HR] = 0.78, 95%CI = 0.67-0.91) in patients with LARC treated with neoadjuvant (chemo) radiotherapy and surgery compared with those in the observation group. Subgroup analysis showed the same results in both the ypStage II and ypStage III groups. Compared with those in the observation group, patients in the chemotherapy group also showed an increase in DFS (HR = 0.75, 95%CI = 0.60-0.93). No significant increase was observed in OS (HR = 1.04, 95%CI = 0.87-1.24) or DFS (HR = 0.98, 95%CI = 0.76-1.27) when oxaliplatin was added to FU-based adjuvant chemotherapy, as compared with the FU-based treatment, and subgroup analysis also indicated no survival benefits in the clinical stage II, clinical stage III, ypStage II, and ypStage III groups.ConclusionsFor patients with LARC who have already received neoadjuvant (chemo) radiotherapy and curative surgery, adjuvant chemotherapy improves OS over that in the observation group. Adding oxaliplatin to FU-based adjuvant chemotherapy does not confer survival benefits beyond those from FU-based adjuvant chemotherapy.
| S-EPMC8319733 | biostudies-literature
Project description:Gastric cancer is among the leading causes of cancer death worldwide. Surgery is the only curative modality, but mortality remains high because a significant number of patients have recurrence after complete surgical resection. Chemotherapy, radiation, and chemoradiotherapy have all been studied in an attempt to reduce the risk for relapse and improve survival. There is no globally accepted standard of care for resectable gastric cancer, and treatment strategies vary across the world. Postoperative chemoradiation with 5-fluorouracil/leucovorin is most commonly practiced in the United States; however, recent clinical trials from Asia have shown benefit of adjuvant chemotherapy alone and have questioned the role of radiation. In this review, we examine the current literature on adjuvant treatment of gastric cancer and discuss the roles of radiation and chemotherapy, particularly in light of these new data and their applicability to the Western population. We highlight some of the ongoing and planned clinical trials in resectable gastric cancer and identify future directions as well as areas where further research is needed.
| S-EPMC3780633 | biostudies-other
Project description:PURPOSE:To develop and validate a robust template for VMAT SBRT of lung lesions, using the multicriterial optimization (MCO) of a commercial treatment planning system. METHODS:The template was established and refined on 10 lung SBRT patients planned for 55 Gy/5 fr. To improve gradient and conformity a ring structure around the planning target volume (PTV) was set in the list of objectives. Ideal fluence optimization was conducted giving priority to organs at risk (OARs) and using the MCO, which further pushes OARs doses. Segmentation was conducted giving priority to PTV coverage. Two different templates were produced with different degrees of modulation, by setting the Fluence Smoothing parameter to Medium (MFS) and High (HFS). Each template was applied on 20 further patients. Automatic and manual plans were compared in terms of dosimetric parameters, delivery time, and complexity. Statistical significance of differences was evaluated using paired two-sided Wilcoxon signed-rank test. RESULTS:No statistically significant differences in PTV coverage and maximum dose were observed, while an improvement was observed in gradient and conformity. A general improvement in dose to OARs was seen, which resulted to be significant for chest wall V30 Gy , total lung V20 Gy , and spinal cord D0.1 cc . MFS plans are characterized by a higher modulation and longer delivery time than manual plans. HFS plans have a modulation and a delivery time comparable to manual plans, but still present an advantage in terms of gradient. CONCLUSION:The automation of the planning process for lung SBRT using robust templates and MCO was demonstrated to be feasible and more efficient.
| S-EPMC7324702 | biostudies-literature
Project description:BackgroundThe newest release of the Eclipse (Varian) treatment planning system (TPS) includes an optimizing engine for Elekta volumetric-modulated arc therapy (VMAT) planning. The purpose of this study was to evaluate this new algorithm and to compare it to intensity-modulated radiation therapy (IMRT) for various disease sites by creating single- and double-arc VMAT plans.MethodsA total of 162 plans were evaluated in this study, including 38 endometrial, 57 head and neck, 12 brain, 10 breast and 45 prostate cancer cases. The real-life IMRT plans were developed during routine clinical cases using the TPS Eclipse. VMAT plans were generated using a preclinical version of Eclipse with tumor-region-specific optimizing templates without interference of the operator: with one full arc (1A) and with two full arcs (2A), and with partial arcs for breast and prostate with hip implant cases. All plans were evaluated based on target coverage, homogeneity and conformity. The organs at risk (OARs) were analyzed according to plan objectives, such as the mean and maximum doses. If one or more objectives were exceeded, the plan was considered clinically unacceptable, and a second VMAT plan was created by adapting the optimization penalties once.ResultsCompared to IMRT, single- and double-arc VMAT plans showed comparable or better results concerning the target coverage: the maximum dose in the target for 1A is the same as that for IMRT; for 2A, an average reduction of 1.3% over all plans was observed. The conformity showed a statistically significant improvement for both 1A (+3%) and 2A (+6%). The mean total body dose was statistically significant lower for the considered arc techniques (IMRT: 16.0 Gy, VMAT: 15.3 Gy, p < 0.001). However, the sparing of OARs shows individual behavior that depends strongly on the different tumor regions. A clear difference is found in the number of monitor units (MUs) per plan: VMAT shows a reduction of 31%.ConclusionThese findings demonstrate that based on optimizing templates with minimal interaction of the operator, the Eclipse TPS is able to achieve a plan quality for the Elekta VMAT delivery technique that is comparable to that of fixed-field IMRT. Plans with two arcs show better dose distributions than plans with one arc.
| S-EPMC4107584 | biostudies-literature
Project description:Purpose: There is currently a lack of validated predictors for adjuvant chemotherapy efficacy in patients with gastric cancer (GC). Perineural invasion (PNI) is the process of neoplastic invasion of the nerves, accompanied by tumor microenvironment (TME) changes. TME can determine treatment outcome while the impact of PNI on chemotherapy efficacy remains unknown in GC. We investigated the association between PNI and the efficacy of postoperative adjuvant chemotherapy in patients with resected GC. Methods: Patients who underwent radical resection of stage IB-III GC with or without fluoropyrimidine (FU)-based adjuvant chemotherapy were retrospectively selected from two separate patient cohorts. PNI was confirmed with S100 immunohistochemistry (IHC). Tumor hypoxia and activity of selected pathways were quantified by mRNA-based signature scoring based on publicly available data. A hypoxia biomarker, ERO1A, and a FU resistance biomarker, thymidylate synthase (TS), were assessed by IHC, respectively. Results: Two cohorts included 223 and 599 patients, respectively. Adjuvant chemotherapy significantly improved overall survival (OS) and disease-free survival (DFS) in PNI-positive but not in PNI-negative patients, which was not impacted by stages. Multivariate models showed that adjuvant chemotherapy was an independent predictor for OS and DFS in PNI-positive patients in both cohorts. For TME, PNI-negative tumors were more hypoxic than were PNI-positive tumors, and displayed relative up-regulation of signaling along the pathways that are important in FU metabolism or resistance. Expressions of ERO1A and TS significantly decreased in PNI-positive compared to PNI-negative tumors. Conclusions: PNI might help predict adjuvant chemotherapy benefit in patients with resected GC. Validation in prospective studies is required. Novel treatment strategies need to be developed in PNI-negative patients.
| S-EPMC7186485 | biostudies-literature
Project description:BackgroundHypofractionated whole-breast irradiation is a standard adjuvant therapy for early-stage breast cancer. This study evaluates the plan quality and efficacy of an in-house-developed automated radiotherapy treatment planning algorithm for hypofractionated whole-breast radiotherapy.MethodsA cohort of 99 node-negative left-sided breast cancer patients completed hypofractionated whole-breast irradiation with six-field IMRT for 42.56 Gy in 16 daily fractions from year 2016 to 2018 at a tertiary center were re-planned with an in-house-developed algorithm. The automated plan-generating C#-based program is developed in a Varian ESAPI research mode. The dose-volume histogram (DVH) and other dosimetric parameters of the automated and manual plans were directly compared.ResultsThe average time for generating an autoplan was 5 to 6 min, while the manual planning time ranged from 1 to 1.5 h. There was only a small difference in both the gantry angles and the collimator angles between the autoplans and the manual plans (ranging from 2.2 to 5.3 degrees). Autoplans and manual plans performed similarly well in hotspot volume and PTV coverage, with the autoplans performing slightly better in the ipsilateral-lung-sparing dose parameters but were inferior in contralateral-breast-sparing. The autoplan dosimetric quality did not vary with different breast sizes, but for manual plans, there was worse ipsilateral-lung-sparing (V4Gy) in larger or medium-sized breasts than in smaller breasts. Autoplans were generally superior than manual plans in CI (1.24 ± 0.06 vs. 1.30 ± 0.09, p < 0.01) and MU (1010 ± 46 vs. 1205 ± 187, p < 0.01).ConclusionsOur study presents a well-designed standardized fully automated planning algorithm for optimized whole-breast radiotherapy treatment plan generation. A large cohort of 99 patients were re-planned and retrospectively analyzed. The automated plans demonstrated similar or even better dosimetric quality and efficacy in comparison with the manual plans. Our result suggested that the autoplanning algorithm has great clinical applicability potential.
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Project description:Currently, adjunctive therapy for gastric cancer is not standardized worldwide and the most effective combination of different modalities has not been clearly determined. The aim of the present study was to retrospectively analyze the efficacy and toxicity of the combination of perioperative epirubicin, capecitabine and oxaliplatin (EOX) chemotherapy and postoperative concurrent chemoradiotherapy in the treatment of locally advanced gastric cancer. A total of 41 patients with locally advanced gastric cancer who had undergone perioperative EOX chemotherapy and surgical resection followed by chemoradiotherapy, were assessed. The perioperative EOX regimen consisted of 50 mg/m2 epirubicin and 130 mg/m2 oxaliplatin on day 1, with 625 mg/m2 capecitabine administered twice daily on days 1-21. The perioperative regimen was repeated 2-3 times every 3 weeks. After complete resection following the perioperative EOX regimen, concurrent chemoradiotherapy with capecitabine (4,500 cGy in daily fractions of 180 cGy administered 5 days per week for 5 weeks, with 625 mg/m2 capecitabine twice daily during radiotherapy) and 2 cycles of the EOX regimen 4 weeks after radiotherapy, were performed. In total, 30/41 patients (73.2%) completed all the planned treatments, including perioperative chemotherapy, surgical resection and chemoradiotherapy. The effective rate of preoperative chemotherapy (partial and complete response) was 56.1%; 30/41 patients received R0 resection, and the overall 3-year survival rate was 57.7%. Grade 3/4 gastrointestinal toxicity (nausea/vomiting) occurred in 22% of the patients, while 18 patients (43.9%) developed grade 3/4 hematological toxicity (granulocytopenia). The results of the present study indicated that the combination of perioperative EOX chemotherapy and postoperative concurrent chemoradiotherapy is feasible and effective for locally advanced gastric cancer.
| S-EPMC5532677 | biostudies-other
Project description:Aim:To validate the Acuros®XB (AXB) dose calculation algorithm for a 6 MV beam from the Varian TrueBeam treatment units. Background:Currently Anisotropic Analytic Algorithm (AAA) is clinically used on authors' department but AXB could replace it for VMAT treatments in regions where inhomogeneities and free air are present. Materials and methods:Two steps are followed in the validation process of a new dose calculation algorithm. The first is to check the accuracy of algorithm for a homogenous phantom and regular fields. Multiple fields of increasing complexity have been acquired using a Mapcheck diode array. The accuracy of the algorithm was evaluated using the gamma analysis method. The second is to validate the algorithm in the presence of heterogeneous media. Planar absolute dose was measured with GafChromic®EBT2 film and was compared with the dose calculated by AXB. Gamma analysis was performed between Mapcheck measurements and AXB dose calculations, at a range of clinical source-surface distance. Results:For SSDs ranging from 80 to 100 cm, the results show a minimum pass rate of 95% between AXB and Mapcheck acquisition. For open 6 MV photon beam interacting with a phantom with an air gap, the agreement after the air gap between AXB and GafChromic®EBT2 is less than 1% in the 3 × 3cm2 field and less than 2% in the 10 × 10 cm2 field. Conclusions:AXB has advanced modelling of lateral electron transport that enables a more accurate dose calculation in heterogeneous regions and, compared with AAA, improves accuracy between different density interfaces. This will be of particular benefit for head/neck treatments.
| S-EPMC7256059 | biostudies-literature
Project description:PURPOSE:Knowledge-based planning (KBP) techniques have been reported to improve plan quality, efficiency, and consistency in radiation therapy. However, plan complexity and deliverability have not been addressed previously for treatment plans guided by an established in-house KBP system. The purpose of this work was to assess dosimetric, mechanical, and delivery properties of plans designed with a common KBP method for prostate cases treated via volumetric modulated arc therapy (VMAT). METHODS:Thirty-one prostate patients previously treated with VMAT were replanned with an in-house KBP method based on the overlap volume histogram. VMAT plan complexities of the KBP plans and the reference clinical plans were quantified via monitor units, modulation complexity scores, the edge metric, and average leaf motion per degree of gantry rotation. Each set of plans was delivered to the same diode array and agreement between computed and measured dose distributions was evaluated using the gamma index. Varying percent dose-difference (1-3%) and distance-to-agreement (1 mm to 3 mm) thresholds were assessed for gamma analyses. RESULTS:Knowledge-based planning (KBP) plans achieved average reductions of 6.4 Gy (P < 0.001) and 8.2 Gy (P < 0.001) in mean bladder and rectum dose compared to reference plans, while maintaining clinically acceptable target dose. However, KBP plans were significantly more complex than reference plans in each evaluated metric (P < 0.001). KBP plans also showed significant reductions (P < 0.05) in gamma passing rates at each evaluated criterion compared to reference plans. CONCLUSIONS:While KBP plans had significantly reduced bladder and rectum dose, they were significantly more complex and had significantly worse quality assurance outcomes than reference plans. These results suggest caution should be taken when implementing an in-house KBP technique.
| S-EPMC6964749 | biostudies-literature
Project description:Even with advanced inverse-planning techniques, radiation treatment plan opti-mization remains a very time-consuming task with great output variability, which prompted the development of more automated approaches. One commercially available technique mimics the actions of experienced human operators to pro-gressively guide the traditional optimization process with automatically created regions of interest and associated dose-volume objectives. We report on the initial evaluation of this algorithm on 10 challenging cases of locoreginally advanced head and neck cancer. All patients were treated with VMAT to 70 Gy to the gross disease and 56 Gy to the elective bilateral nodes. The results of post-treatment autoplanning (AP) were compared to the original human-driven plans (HDP). We used an objective scoring system based on defining a collection of specific dosimetric metrics and corresponding numeric score functions for each. Five AP techniques with different input dose goals were applied to all patients. The best of them averaged the composite score 8% lower than the HDP, across the patient population. The difference in median values was statistically significant at the 95% confidence level (Wilcoxon paired signed-rank test p = 0.027). This result reflects the premium the institution places on dose homogeneity, which was consistently higher with the HDPs. The OAR sparing was consistently better with the APs, the differences reaching statistical significance for the mean doses to the parotid glands (p < 0.001) and the inferior pharyngeal constrictor (p = 0.016), as well as for the maximum doses to the spinal cord (p = 0.018) and brainstem (p = 0.040). If one is prepared to accept less stringent dose homogeneity criteria from the RTOG 1016 protocol, nine APs would comply with the protocol, while providing lower OAR doses than the HDPs. Overall, AP is a promising clinical tool, but it could benefit from a better process for shifting the balance between the target dose coverage/homogeneity and OAR sparing.
| S-EPMC5690942 | biostudies-literature