Critical appraisal of the role of volumetric modulated arc therapy in the radiation therapy management of breast cancer

Background: The aim of this review is the critical appraisal of the current use of volumetric modulated arc therapy for the radiation therapy management of breast cancer. Both clinical and treatment planning studies were investigated. Material and methods: A Pubmed/MEDLINE search of the National Library of Medicine was performed to identify VMAT and breast related articles. After a first order rejection of the irrelevant findings, the remaining articles were grouped according to two main categories: clinical vs. planning studies and to some sub-categories (pointing to significant technical features). Main areas of application, dosimetric and clinical findings as well as areas of innovations were defined. Results: A total of 131 articles were identified and of these, 67 passed a first order selection. Six studies reported clinical results while 61 treatment dealed with treatment planning investigations. Among the innovation lines, the use of high intensity photon beams (flattening filter free), altered fractionation schemes (simultaneous integrated boost, accelerated partial breast irradiation, single fraction), prone positioning and modification of standard VMAT (use of dynamic trajectories or hybrid VMAT methods) resulted among the main relevant fields of interest. Approximately 10% of the publications reported upon respiratory gating in conjunction with VMAT. Conclusions: The role of VMAT in the radiation treatment of breast cancer seems to be consolidated in the in-silico arena while still limited evidence and only one phase II trial appeared in literature from the clinical viewpoint. More clinical reports are needed to fully proove the expected dosimetric benefits demonstrated in the planning investigations

Modern Radiotherapy Era in Breast Cancer

Radiation therapy (RT) is one of the major treatment modalities that are used in breast cancer treatment, and depending on the chest-wall anatomy, RT fields have to be customized. Techniques used in planning have been evolving since last two decades from two dimensional (2D) to three-dimensional (3D), while intensity modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT) and even proton therapy have been an option in daily approach. In addition, technological hardware and software advances in delivery and planning systems, total treatment duration of breast RT have been shortened in last decades along with recent hypofractionated radiotherapy schemes or emerging partial-breast irradiation protocols. The other attractive approach—accelerated partial breast irradiation (APBI) could be a reasonable option for highly selected subpopulation of early-stage breast cancer patients out of a clinical trial. Long-term follow-up results have emerged heart and coronary sparing with maximum safety and efficacy. The most important advance could be named as cardiac sparing—deep breath-hold approach—in all the modern technique improvement. Although most advanced techniques in management of breast cancer have not been verified to increase survival, we suggest recommending resource stratified advanced in order to provide best technical and clinical care in this long-term survivor candidates

Fondazione Italiana Linfomi (FIL) expert consensus on the use of intensity-modulated and image-guided radiotherapy for Hodgkin's lymphoma involving the mediastinum

Advances in therapy have resulted in improved cure rates and an increasing number of long-term Hodgkin's lymphoma (HL) survivors. However, radiotherapy (RT)-related late effects are still a significant issue, particularly for younger patients with mediastinal disease (secondary cancers, heart diseases). In many Centers, technological evolution has substantially changed RT planning and delivery. This consensus document aims to analyze the current knowledge of Intensity-Modulated Radiation Therapy (IMRT) and Image-Guided Radiation Therapy (IGRT) for mediastinal HL and formulate practical recommendations based on scientific evidence and expert opinions

Dosimetric Comparison between Dynamic Wave Arc and Co-Planar Volumetric Modulated Radiotherapy for Locally Advanced Pancreatic Cancer

Introduction: Dose reduction to the duodenum is important to decrease gastrointestinal toxicities in patients with locally advanced pancreatic cancer (LAPC) treated with definitive chemoradiotherapy. We aimed to compare dynamic wave arc (DWA), a volumetric-modulated beam delivery technique with simultaneous gantry/ring rotations passing the waved trajectories, with coplanar VMAT (co-VMAT) with respect to dose distributions in LAPC cases. Material and Methods: DWA and co-VMAT plans were created for 13 patients with LAPC. The prescribed dose was 45.6 or 48 Gy in 15 fractions. The dose volume indices (DVIs) for target volumes and organs at risk were compared between the corresponding plans. Gamma passing rate, monitor unit (MU), and beam-on time were also compared. Results: DWA significantly reduced the duodenal V39Gy, V42Gy, and V45Gy by 1.1, 0.8, and 0.2 cm3, and increased the liver mean dose and D2cm3 of the spinal cord planning volume by 1.0 and 1.5 Gy, respectively. Meanwhile, there was no significant difference in the target volumes except for D2% of PTV (111.5% in DWA vs. 110.5% in co-VMAT). Further, the gamma passing rate was similar in both plans. MU and beam-on time increased in DWA by 31 MUs and 15 seconds, respectively. Conclusion: DWA generated significantly lower duodenal doses in LAPC cases, albeit with slight increasing liver and spinal cord doses and increasing MU and the beam delivery time. Further evaluation is needed to know how the dose differences would affect the clinical outcomes in chemoradiotherapy for LAPC

Developing the Role of Proton Beam Therapy in Oesophageal Cancer

Oesophageal cancer continues to be associated with a poor prognosis. Proton beam therapy’s distinct physical characteristics widen the therapeutic ratio in oesophageal cancer and has the potential to improve outcomes. This thesis aims to examine how proton beam therapy may improve outcomes in oesophageal cancer and documents efforts to expand its role. In Chapter 2, a comprehensive systematic literature review demonstrates the paucity of high-quality evidence in this field. Following this, a series of radiotherapy planning studies investigates potential dosimetric advantages of proton beam therapy for distal oesophageal cases. In chapter 3, proton beam therapy is shown to reduce lung and heart dose compared to photon radiotherapy. Normal tissue complication probability modelling establishes that this may reduce the risk of treatment related pulmonary and cardiac toxicity. Chapter 4 demonstrates that spleen dose constraints may successfully be introduced in oesophageal cancer for proton and photon plans, potentially resulting in lower lymphopenia rates and greater immune sparing. Chapter 5 highlights the impact of different beam arrangements on dose to organs at risk and individual cardiac substructures. The latter half of the thesis highlights work underpinning the development of novel clinical trials of proton beam therapy in oesophageal cancer. Chapter 6 details the work of creating a radiotherapy delineation protocol by comparing two established protocols in a delineation comparison study, showing that geometric expansion of volumes results in more consistent target volumes compared to ‘free-hand’ delineation. In chapter 7, public and patient involvement work is shown to inform and refine the design of a two new trials of proton beam therapy in oesophageal cancer. A final chapter discusses and summarises the current areas of interest in this field, expanding on current trial development work and future directions

Benefits and limitations of volumetric modulated arc therapy in treating bilateral breast cancer with regional lymph nodes

Purpose: The study was performed comparing dosimetric characteristics of volumetric modulated arc therapy (VMAT) and field-in-field (FiF) techniques on a patient with synchronous bilateral breast carcinoma. Methods: The patients with bilateral breast cancer treatment were included in this study. A total dose of 40.05 Gy in 15 fractions was prescribed to the Planning Target Volume (PTV) of the whole bilateral breast cancer with the supraclavicular and infraclavicular nodes, with a complementary boost of 10 Gy in 4 fractions to the surgical bed (PTVboost). For both radiotherapy techniques, several VxGy parameters were analyzed for the PTVs, together with the Conformity index (CI), the Homogeneity index (HI) and the critical organs at risk (OARs), lungs and heart. Results: The patient was treated by the VMAT technique and the daily treatment time was less than 20 minutes with daily CBCT imaging. In the VMAT plan, the PTV 95% dose covered 38.89 ± 0.81 Gy, compared to 37.26 ± 1.02 Gy in the FiF technique. The VMAT plan improved the dose homogeneity index and lower dose in lung towards high dose region. Conclusion: The study demonstrates the viability of the VMAT technique in the treatment of bilateral breast cancer. The introduced single isocentric VMAT technique is fast to deliver and it increases the dose homogeneity of the target volume with some limitations. The treatment was well tolerated, without interruption of the treatment courses caused by treatmentrelated toxicities

Dosimetric comparison of 3-dimensional conformal technique, intensity-modulated, volumetric arc modulation, and helical tomotherapy with radixact in patients with breast cancer

OBJECTIVE Adjuvant radiotherapy (RT) has been used often at breast cancer treatment. RT techniques differ from each other in terms of accessibility and applicability. We aimed to compare the dosimetric evaluations of four modern RT techniques through ten breast cancer patients that had been treated previously with intensity-modulated RT (IMRT) technique. METHODS A single-center dosimetric study was performed based on treatment plannings of left-sided breast cancer patients. The patient’s images, simulated at computed tomography with deep inspiration breath hold technique between March and June 2023, were used. Four different techniques, field-in-field (FinF), dynamic IMRT (dIMRT), volumetric modulated arc treatment (VMAT), and helical therapy (HT) were created on each patient image. Conformal index (CI) and homogeneity index (HI) were calculated. Mean doses of heart, contralateral breast, volume of doses 5 Grey (Gy) (V5) and 10 Gy (V10) of left lung and total lungs were also calculated for each plan and the descripted and comparisons analysis was performed. RESULTS The better results of CI and HI were reported with dIMRT, VMAT, and HT techniques. However, these approaches were expected with increased percentage of lower doses at organs at risk (OAR). The lowest of V5 of left and total lungs, mean heart, and contralateral breast doses were achieved with FinF tech-niques, HT values were observed similar to FinF by these factors at OAR. Particularly, the lowest V20 value was demonstrated at HT techniques. CONCLUSION Adjuvant RT techniques at breast cancer still carry controversial subtitles. New technologic improvements might be indispensable and treatment plannings should be based on the individual properties of patients