Chest wall pain after single-fraction thoracic stereotactic ablative Radiotherapy: Dosimetric analysis from the iSABR trial.

BACKGROUND AND PURPOSE: Concerns over chest wall toxicity has led to debates on treating tumors adjacent to the chest wall with single-fraction stereotactic ablative radiotherapy (SABR). We performed a secondary analysis of patients treated on the prospective iSABR trial to determine the incidence and grade of chest wall pain and modeled dose-response to guide radiation planning and estimate risk. MATERIALS AND METHODS: This analysis included 99 tumors in 92 patients that were treated with 25 Gy in one fraction on the iSABR trial which individualized dose by tumor size and location. Toxicity events were prospectively collected and graded based on the CTCAE version 4. Dose-response modeling was performed using a logistic model with maximum likelihood method utilized for parameter fitting. RESULTS: There were 22 grade 1 or higher chest wall pain events, including five grade 2 events and zero grade 3 or higher events. The volume receiving at least 11 Gy (V11Gy) and the minimum dose to the hottest 2 cc (D2cc) were most highly correlated with toxicity. When dichotomized by an estimated incidence of ≥ 20 % toxicity, the D2cc > 17 Gy (36.6 % vs. 3.7 %, p < 0.01) and V11Gy > 28 cc (40.0 % vs. 8.1 %, p < 0.01) constraints were predictive of chest wall pain, including among a subset of patients with tumors abutting or adjacent to the chest wall. CONCLUSION: For small, peripheral tumors, single-fraction SABR is associated with modest rates of low-grade chest wall pain. Proximity to the chest wall may not contraindicate single fractionation when using highly conformal, image-guided techniques with sharp dose gradients.

Radiotherapy in Preclinical Models of Brain Metastases: A Review and Recommendations for Future Studies.

Brain metastases (BMs) frequently occur in primary tumors such as lung cancer, breast cancer, and melanoma, and are associated with notably short natural survival. In addition to surgical interventions, chemotherapy, targeted therapy, and immunotherapy, radiotherapy (RT) is a crucial treatment for BM and encompasses whole-brain radiotherapy (WBRT) and stereotactic radiosurgery (SRS). Validating the efficacy and safety of treatment regimens through preclinical models is imperative for successful translation to clinical application. This not only advances fundamental research but also forms the theoretical foundation for clinical study. This review, grounded in animal models of brain metastases (AM-BM), explores the theoretical underpinnings and practical applications of radiotherapy in combination with chemotherapy, targeted therapy, immunotherapy, and emerging technologies such as nanomaterials and oxygen-containing microbubbles. Initially, we provided a concise overview of the establishment of AM-BMs. Subsequently, we summarize key RT parameters (RT mode, dose, fraction, dose rate) and their corresponding effects in AM-BMs. Finally, we present a comprehensive analysis of the current research status and future directions for combination therapy based on RT. In summary, there is presently no standardized regimen for AM-BM treatment involving RT. Further research is essential to deepen our understanding of the relationships between various parameters and their respective effects.

Implicaciones de la pandemia en la radioterapia para el cáncer de mama. Radioterapia hipofraccionada / Implications of the pandemic in radiotherapy for breast cancer. Hypofractionated radiation therapy

La pandemia por el nuevo coronavirus (SARS-CoV-2) ha puesto a prueba los sistemas de salud de todo el mundo, de una forma tan apremiante que no se veía hace muchos años. Las implicaciones en la atención en salud no afectan únicamente a los pacientes con la COVID-19, sino que son transversales a todas las enfermedades. Específicamente en cáncer de mama, los esquemas de radioterapia hipofraccionada constituyen una alternativa válida y segura que ayuda a disminuir la exposición de las pacientes al nuevo virus, la congestión de las instituciones de salud y los costos propios de los tratamientos oncológicos especializados. En este artículo, se realizó una revisión de la literatura más relevante sobre los regímenes acortados de radioterapia en cáncer de mama: hipofraccionamiento e hipofraccionamiento extremo, y sobre su equivalencia con el fraccionamiento estándar. Al final, se destacan las recomendaciones de diferentes sociedades científicas y expertos internacionales, para considerar esquemas de radioterapia hipofraccionados, a propósito de la contingencia de salud mundial. (AU)

The current pandemic due to the new coronavirus (SARS-CoV-2) has put health systems around the world to the test, in a way so urgent that had not been seen in several years. The implications in health care not only affect patients with COVID-19, but they are transversal to all pathologies. Specifically in breast cancer, hypofractionated radiotherapy schemes constitute a valid and safe alternative that helps reduce the exposure of patients to the new virus, the congestion of health institutions and the costs of specialized cancer treatments. In this article, we conducted a review of the most relevant literature on shortened radiotherapy regimens in breast cancer: hypofractionation and extreme hypofractionation, and their equivalence with fractionation. In the end, the recommendations of different scientific societies and international experts are highlighted, to consider hypofractionated radiotherapy schemes, regarding the global health contingency. (AU)

Dose escalated simultaneous integrated boost of gross nodal disease in gynecologic cancers: a multi-institutional retrospective analysis and review of the literature.

PURPOSE: Typical doses of 45-50.4 Gy used to treat regional nodes have demonstrated inadequate control of gross nodal disease (GND) in gynecologic cancer, and accelerated repopulation may limit the efficacy of a sequential boost. We reviewed outcomes of patients treated with a simultaneous integrated boost (SIB) at 2.25 Gy per fraction to positron emission tomography (PET) avid GND to evaluate toxicity and tumor control using this dose-escalated regimen. MATERIALS AND METHODS: A total of 83 patients with gynecologic cancer and PET avid inguinal, pelvic, or para-aortic lymphadenopathy were treated using intensity-modulated radiation therapy (IMRT) with SIB. Primary cancers were mostly cervical (51%) and endometrial (34%), and included patients who received concurrent chemotherapy (59%) and/or brachytherapy boost (78%). RESULTS: Median follow-up from radiation completion was 12.6 months (range, 2.7 to 92.9 months). Median dose to elective lymphatics was 50.4 Gy (range, 45 to 50.4 Gy) at 1.8 Gy/fraction. Median SIB dose and volume were 63 Gy (range, 56.3 to 63 Gy) and 72.8 mL (range, 6.8 to 1,134 mL) at 2-2.25 Gy/fraction. Nodal control was 97.6% in the SIB area while 90.4% in the low dose area (p = 0.013). SIB radiotherapy (RT) field failure-free, non-SIB RT field failure-free, and out of RT field failure-free survival at 4 years were 98%, 86%, and 51%, respectively. Acute and late grade ≥3 genitourinary toxicity rates were 0%. Acute and late grade ≥3 gastrointestinal toxicity rates were 7.2% and 12.0%, respectively. CONCLUSION: Dose escalated SIB to PET avid adenopathy results in excellent local control with acceptable toxicity.

Prospective Randomized Phase II Study of Stereotactic Body Radiotherapy (SBRT) vs. Conventional Fractionated Radiotherapy (CFRT) for Chinese Patients with Early-Stage Localized Prostate Cancer.

BACKGROUND: Stereotactic body radiotherapy (SBRT) has potential radiobiologic and economic advantages over conventional fractionated radiotherapy (CFRT) in localized prostate cancer (PC). This study aimed to compare the effects of these two distinct fractionations on patient-reported quality of life (PRQOL) and tolerability. METHODS: In this prospective phase II study, patients with low- and intermediate-risk localized PC were randomly assigned in a 1:1 ratio to the SBRT (36.25 Gy/5 fractions/2 weeks) or CFRT (76 Gy/38 fractions/7.5 weeks) treatment groups. The primary endpoint of variation in PRQOL at 1 year was assessed by changes in the Expanded Prostate Cancer Index Composite (EPIC) questionnaire scores and analysed by z-tests and t-tests. RESULTS: Sixty-four eligible Chinese men were treated (SBRT, n = 31; CFRT, n = 33) with a median follow-up of 2.3 years. At 1 year, 40.0%/46.9% of SBRT/CFRT patients had a >5-point decrease in bowel score (p = 0.08/0.28), respectively, and 53.3%/46.9% had a >2-point decrease in urinary score (p = 0.21/0.07). There were no significant differences in EPIC score changes between the arms at 3, 6, 9 and 12 months, but SBRT was associated with significantly fewer grade ≥ 1 acute and 1-year late gastrointestinal toxicities (acute: 35% vs. 87%, p < 0.0001; 1-year late: 64% vs. 84%, p = 0.03), and grade ≥ 2 acute genitourinary toxicities (3% vs. 24%, p = 0.04) compared with CFRT. CONCLUSION: SBRT offered similar PRQOL and less toxicity compared with CFRT in Chinese men with localized PC.

Lattice radiation therapy - its concept and impact in the immunomodulation cancer treatment era

SUMMARY Voluminous tumors represent a challenge in radiation oncology, particularly when surgical resection is not possible. Lattice radiotherapy (LTR) is a technique that may provide equivalent or superior clinical response in the management of large tumors while limiting toxicity to adjacent normal tissues. LRT can precisely deliver inhomogeneous high doses of radiation to different areas within the gross tumor volumes (GTV). The dosimetric characteristic of LTR is defined by the ratio of the valley dose (lower doses - cold spots) and the peak doses, also called vertex (higher doses - hot spots), or the valley-to-peak dose ratio. The valley-to-peak ratio thereby quantifies the degree of spatial fractionation. LRT delivers high doses of radiation without exceeding the tolerance of adjacent critical structures. Radiobiological experiments support the role of radiation-induced bystander effects, vascular alterations, and immunologic interactions in areas subject to low dose radiation. The technological advancements continue to expand in Radiation Oncology, bringing new safety opportunities of treatment for bulky lesions.

RESUMO Tumores volumosos representam um desafio para a radio-oncologia, em especial quando a ressecção cirúrgica não é possível. A radioterapia com técnica Latisse (LTR) pode gerar resposta clínica equivalente ou superior ao tratamento convencional de grandes tumores, limitando a toxicidade nos tecidos normais adjacentes. A LRT pode fornecer com precisão altas doses não homogêneas de radiação em diferentes áreas do volume tumoral (GTV). A característica dosimétrica da LTR é definida pela razão entre a dose na região do vale (doses mais baixas - pontos frios) e as doses de pico, também chamadas de vértice (doses mais altas - pontos quentes) ou a razão da dose vale/pico. Dessa forma, a razão vale/pico quantifica o grau de fracionamento espacial da entrega de dose. A LRT entrega, dessa forma, altas doses de radiação sem exceder a tolerância de estruturas críticas adjacentes. Experimentos radiobiológicos suportam o chamado "efeito espectador" induzido por radiação, o qual promove alterações vasculares e interações imunológicas, levando à resposta tumoral mesmo em áreas expostas a baixas doses de radiação. Os avanços tecnológicos continuam a se expandir na radio-oncologia, trazendo, por meio da LTR, uma nova oportunidade segura de tratamento para lesões volumosas.

Low-dose hilar and mediastinal stereotactic body radiation therapy for non-small cell lung cancer: Analysis of outcomes in patients receiving one or multiple courses of treatment.

BACKGROUND: This study reports the outcomes of a single institutional experience treating non-small cell lung cancer (NSCLC) involving the pulmonary hilum with low-dose stereotactic body radiation therapy (SBRT). The authors also present a series of repeat hilar SBRT. METHODS: Inclusion criteria required treatment with SBRT for NSCLC involving regional lymph nodes of the: (i) hilum, (ii) mediastinum, (iii) aortopulmonary window (station 5), or (iv) mainstem bronchus. At least one clinical follow-up with imaging was required, unless the patient had a prior documented death from cancer. RESULTS: A total of 32 patients with 44 treatments were included, and 37 treatments targeted the hilum directly, with seven concerning the mediastinum, AP window, or mainstem bronchus. Median dose was 28 Gy in four fractions with once-weekly fractionation. At a median clinical follow-up of 23 months, local control was 64%. Median overall survival was 24 months, and median progression-free survival was 15 months. A total of 48% of treatments resulted in complete radiographic response on last imaging follow-up, and no cases of grade ≥ 3 toxicity were reported. For repeat SBRT (after prior hilar SBRT), local control was 92%. Median overall survival was 20 months, and median progression-free survival was 19 months. Complete radiographic response was noted after 58% of treatments, with 0 instances of progressive response and no reported side effects. CONCLUSIONS: Low-dose hilar SBRT was efficacious and well-tolerated, with impressive overall survival and no grade ≥ 3 toxicity. Repeat treatments with SBRT were feasible and effective, demonstrating overall survival, local control, and toxicity comparable to primary treatments. KEY POINTS: Significant findings of the study Low-dose hilar SBRT was efficacious and well-tolerated Repeated treatments with SBRT demonstrated encouraging results, comparable to primary treatments What this study adds This study contributes to the small body of literature concerning hilar SBRT Repeat hilar SBRT was safe and feasible Toxicity was minimal with low-dose SBRT Once-weekly fractionation may have contributed to low rate of side effects.