Do all the linear accelerators comply with the ICRU 91's constraints for stereotactic body radiation therapy treatments?

Recent technological developments in linear accelerators (linacs) and their imaging systems have made it possible to routinely perform stereotactic radiotherapy (SRT) treatments. To ensure the security and quality of the treatments, national and international recommendations have been written. This review focuses on the recommendations of the report 91 of the International Commission on Radiation Units (ICRU) on stereotactic treatments with small photon beams and proposes to answer the question of the eligibility of the commercially available accelerators for the treatment of extra-cranial SRT (SBRT). The ICRU 91 report outlines important features needed to respect the constraints, which are high intensity photon beam, integrated image-guidance, high mechanical accuracy of the linac, multileaf collimator with reduced leaf width, bundled motion management and bundled 6 Dimensional “robotic” couch tabletop. Most of the contemporary linacs meet these recommendations, in particular, stereotactic dedicated linacs, or modern gantry-based linacs equipped with 3 dimensional cone-beam CT imaging and 2D-stereoscopic planar imaging. Commercially available ring-based linacs have some limitations: they offer only coplanar treatments, and couch movements are limited to translations and, some have limited imaging equipment and no ability to manage intrafraction motion. However, for performing SBRT, non-coplanar irradiations are not mandatory, contrarily to intracranial stereotactic irradiations. Furthermore, patients’ rotations can be corrected, thanks to real-time adaptive radiotherapy available on MRI-linacs. Finally, significant improvements are expected in the short term to compensate the weaknesses of the current devices.     

Can surgery improve local control in small cell lung cancer?

Current therapy for small cell lung cancer (SCLC) consists of chemotherapy with or without radiotherapy. Radiotherapy is generally accepted as an essential treatment component of limited stage disease. However, the local failure rate after chemo- and radiotherapy is still high and ranges from 30 to 70%. Furthermore, despite having obtained a complete radiographic response, up to 75% of these patients will have residual disease in the tumor specimen, if resection is performed. Therefore, more effective means are needed to eradicate the primary tumor and to obtain an improved local disease control. Recent phase two trials of multimodal regimens for stage I-IIIA SCLC demonstrate that in selected patients with early stage SCLC the combination of surgery and chemotherapy with or without radiotherapy is feasible with low morbidity and mortality rates. The combination therapy results in satisfying long term outcome depending on the pathological tumor stage and a local disease control is achieved in almost all patients. It is remarkable that the pneumonectomy rate has decreased over the past decades from almost 100 to 27-39%. In order to confirm these promising results, a German multicenter prospective randomized phase III trial has been designed for patients with stage I-IIIA SCLC consisting of induction chemotherapy, followed by surgery, adjuvant thoracic radiotherapy and prophylactic cranial radiation compared to thoracic radiotherapy and prophylactic cranial radiation.     

Single-fraction stereotactic ablative body radiation therapy for primary and metastasic lung tumor: A new paradigm?

Stereotactic ablative body radiotherapy (SABR) is an effective technique comparable to surgery in terms of local control and efficacy in early stages of non-small cell lung cancer (NSCLC) and pulmonary metastasis. Several fractionation schemes have proven to be safe and effective, including the single fraction (SF) scheme. SF is an option cost-effectiveness, more convenience and comfortable for the patient and flexible in terms of its management combined with systemic treatments. The outbreak of the severe acute respiratory syndrome coronavirus 2 pandemic has driven this not new but underutilized paradigm, recommending this option to minimize patients’ visits to hospital. SF SABR already has a long experience, strong evidence and sufficient maturity to reliably evaluate outcomes in peripheral primary NSCLC and there are promising outcomes in pulmonary metastases, making it a valid treatment option; although its use in central locations, synchronous and recurrencies tumors requires more prospective safety and efficacy studies. The SABR radiobiology study, together with the combination with systemic therapies, (targeted therapies and immunotherapy) is a direction of research in both advanced disease and early stages whose future includes SF.     

The tolerance of gastrointestinal organs to stereotactic body radiation therapy: what do we know so far?

As stereotactic body radiation therapy (SBRT) for gastrointestinal (GI) gains popularity, there is a need to optimize doses and fractionation to minimize GI toxicity. GI organs that have classically developed radiation-induced toxicity include the liver & biliary system, small bowel, esophagus, and rectum. While the literature quantifies dose restrictions for these organs under standard fractionation, there is limited data regarding toxicity with the ablative dose schedules used in SBRT. We conducted a review of the literature to identify prospective and retrospective studies that detail GI toxicities when SBRT was employed. Based on the literature, the median SBRT dose for abdominal and thoracic tumors ranged from 24 to 60 Gy, at 5 to 25 Gy per fraction. The respective observed frequencies of grade 3 and 4 toxicities for the liver, biliary system, small bowel, and esophagus were variable among different studies. Typically, patients who suffered grade 3 and 4 toxicities were more likely to have had some form of systemic therapy as well. The effect of dose, fractionation, timing, and volume on GI toxicities has been described in the literature but more data is necessary to develop uniform treatment guidelines for SBRT.     

Does locoregional radiation therapy improve survival in breast cancer? A meta-analysis.

PURPOSE: Recent randomized trials in women with node-positive breast cancer who received systemic treatment report that locoregional radiation therapy improves survival. Previous trials failed to detect a difference in survival that results from its use. A systematic review of randomized trials that examine the effectiveness of locoregional radiation therapy in patients treated by definitive surgery and adjuvant systemic therapy was conducted. METHODS: Randomized trials published between 1967 and 1999 were identified through MEDLINE database, CancerLit database, and reference lists of relevant articles. Relevant data was abstracted. The results of randomized trials were pooled using meta-analyses to estimate the effect of treatment on any recurrence, locoregional recurrence, and mortality. RESULTS: Eighteen trials that involved a total of 6,367 patients were identified. Most trials included both pre- and postmenopausal women with node-positive breast cancer treated with modified radical mastectomy. The type of systemic therapy received, sites irradiated, techniques used, and doses of radiation delivered varied between trials. Data on toxicity were infrequently reported. Radiation was shown to reduce the risk of any recurrence (odds ratio, 0.69; 95% confidence interval [CI], 0.58 to 0.83), local recurrence (odds ratio, 0.25; 95% CI, 0.19 to 0.34), and mortality (odds ratio, 0.83; 95% CI, 0.74 to 0.94). CONCLUSION: Locoregional radiation after surgery in patients treated with systemic therapy reduced mortality. Several questions remain on how these results should be translated into current-day clinical practice.     

The expanding role of stereotactic body radiation therapy in oligometastatic solid tumors: What do we know and where are we going?

The spectrum hypothesis posits that there are distinct clinical states of metastatic progression. Early data suggest that aggressive treatment of more biologically indolent metastatic disease, characterized by metastases limited in number and destination organ, may offer an opportunity to alter the disease course, potentially allowing for longer survival, delay of systemic therapy, or even cure. The development of stereotactic body radiation therapy (SBRT) has opened new avenues for the treatment of oligometastatic disease. Early data support the use of SBRT for treating oligometastases in a number of organs, with promising rates of treated metastasis control and overall survival. Ongoing investigation is required to definitively establish benefit, determine the appropriate treatment regimen, refine patient selection, and incorporate SBRT with systemic therapies.     

Stereotactic body radiation therapy in the re-irradiation situation – a review

Although locoregional relapse is frequent after definitive radiotherapy (RT) or multimodal treatments, re-irradiation is only performed in few patients even in palliative settings like e.g. vertebral metastasis. This is most due to concern about potentially severe complications, especially when large volumes are exposed to re-irradiation. With technological advancements in treatment planning the interest in re-irradiation as a local treatment approach has been reinforced. Recently, several studies reported re-irradiation for spinal metastases using SBRT with promising local and symptom control rates and simultaneously low rates of toxicity. These early data consistently indicate that SBRT is a safe and effective treatment modality in this clinical situation, where other treatment alternatives are rare. Similarly, good results have been shown for SBRT in the re-irradiation of head and neck tumors. Despite severe late adverse effects were reported in several studies, especially after single fraction doses >10 Gy, they appear less frequently compared to conventional radiotherapy. Few studies with small patient numbers have been published on SBRT re-irradiation for non-small cell lung cancer (NSCLC). Overall survival (OS) is limited by systemic progression and seems to depend particularly on patient selection. SBRT re-irradiation after primary SBRT should not be practiced in centrally located tumors due to high risk of severe toxicity. Only limited data is available for SBRT re-irradiation of pelvic tumors: feasibility and acceptable toxicity has been described, suggesting SBRT as a complementary treatment modality for local symptom control.     

Efficacy and safety evaluation of stereotactic body radiation therapy based on tomotherapy for hepatocellular carcinoma北大核心CSCD

Objective: To evaluate the primary outcomes and adverse reactions of patients with hepatocellular carcinoma treated by stereotactic body radiation therapy (SBRT) using tomotherapy. Methods: From December 2012 to December 2015, Forty-six patients with hepatocellular carcinoma who received SBRT in Zhongshan Hospital Affiliated to Fudan University were enrolled. The clinical and pathological data and follow-up data of all cases were collected. The median diameter of tumors was 2.5 cm, ranging from 0.9 to 5.8 cm. All cases were performed by four-dimensional CT (4-DCT) scan and image-guided matching calibration before SBRT. Total irradiation dose ranged from 48 to 50 Gy in 5 to 10 fractions. The supportive treatments of liver protection and nutritional support were administrated during SBRT. The curative tumor response was evaluated using the modifed Response Evaluation and Criteria in Solid Tumors (mRECIST) 6 months after SBRT. The adverse reactions were evaluated using National Cancer Institute- Common Terminology Criteria for Adverse Events 3.0 (NCI-CTC 3.0). The cumulative probability of survival was calculated according to Kaplan-Meier method. Results: All cases completed SBRT. They were followed up every 3 months after treatment. Based on mRECIST, 58.7% of patients achieved complete response (CR), 32.6% achieved partial response (PR), and there were 4.3% patients with stable disease, and 2.61% patients with tumor progression. The total effective rate (CR+PR) was 91.3%. The overall survival (OS) rates at 1, 2 and 3 years were 95.4%, 75.7% and 69.9%, respectively. For the adverse reaction, only 5 cases of grade? bone marrow suppression, 2 cases of gradeII bone marrow suppression and 2 cases of grade? transaminase increase were found; no radiation-induced liver disease (RILD) occurred. Conclusion: Tomotherapy is a safe and effective treatment for the patients with unresectable hepatocellular carcinoma. So SBRT using tomotherapy is worth promoting as an alternative treatment for unresectable hepatocellular carcinoma unsuitable for standard treatment. Copyright © 2017 by TUMOR All rights reserved.     

Do antioxidants interfere with radiation therapy for cancer?

Despite recent comprehensive review articles concluding that supplemental antioxidants do not undermine the effectiveness of cytotoxic therapies, the use of antioxidants during cancer treatment remains controversial. Many oncologists take the position that antioxidants by their nature undermine the free radical mechanism of chemotherapy and radiotherapy and should therefore generally be avoided during treatment. For their part, many integrative practitioners believe that antioxidants taken during cancer treatment not only alleviate some of the adverse effects of that treatment but also enhance the efficacy of cancer therapy. Until recently, research attention has focused primarily on the interaction of antioxidants with chemotherapy; relatively little attention has been paid to the interaction of antioxidants with radiotherapy. This article reviews the clinical literature that has addressed whether antioxidants do in fact interfere with radiation therapy. Studies have variously investigated the use of alpha-tocopherol for the amelioration of radiation-induced mucositis; pentoxifylline and vitamin E to correct the adverse effects of radiotherapy; melatonin alongside radiotherapy in the treatment of brain cancer; retinol palmitate as a treatment for radiation-induced proctopathy; a combination of antioxidants (and other naturopathic treatments) and external beam radiation therapy as definitive treatment for prostate cancer; and the use of synthetic antioxidants, amifostine, dexrazoxane, and mesna as radioprotectants. With few exceptions, most of the studies draw positive conclusions about the interaction of antioxidants and radiotherapy. Although further studies are needed, the preponderance of evidence supports a provisional conclusion that dietary antioxidants do not conflict with the use of radiotherapy in the treatment of a wide variety of cancers and may significantly mitigate the adverse effects of that treatment.     

Gefitinib combined with γ-ray stereotactic body radiation therapy has better efficacy than gefitinib alone for senile lung adenocarcinoma patients with EGFR mutations as first-line regimen

Objective： The senile lung adenocarcinoma patients harboring an activating epidermal growth factor receptor （EGFR） mutation shows good and rapid response to EGFR tyrosine kinase inhibitors （TKIs）. Whether gefitinib combined with y-ray stereotactic body radiation therapy has better efficacy than gefitinib alone for senile lung adenocarcinoma patients with EGFR mutations as first-line regimen is still under investigation. Methods： The 42 senile lung adenocarcinoma patients with EGFR mutations were divided into 2 groups according to the therapy method. Group A was the 22 patients treated with gefitinib combined with y-ray stereotactic body radiation therapy （SBRT）. Group B was the 20 patients treated with gefitinib alone. All of the patients received gefitinib of 250 mg/d from the first day until disease progression or other reasons. The patients of Group A were treated with y-ray stereotactic body radiation therapy from the second day. Radiation fields included the primary lesions and the integration of lymph nodes. Dose curve of this group was 50%-80%. Encircled dose was 4.0-6.5 Gy per fraction and the range of total dose was 40-52 Gy. We treated the patients 8-12 times and treated five times every week. Results： All the patients were examined by enhanced double helix CT at the second month. The tumor response rate （RR） of group A was 81.8% （18/22）. Disease control rate （DCR） was 90.9% （20/22）. The median overall survival （OS） was 24.2 months （range 8-58 months ） and the progression-free survival （PFS） was 18.6 months. The overall 1-year survival rate was 72.3% （16/22） and 2-year survival rate was 54.5% （12/22）. The main side effects included skin rash and diarrhea. The RR of group B was 50.0 % （10/20）. DCR was 75.0% （15/20）. OS was 17.4 months （range 6-32 months ） and PFS was 12.1 months. The overall 1-year survival rate was 60.0% （12/20） and 2-year survival rate was 40.0% （8/20）. The main side effects included skin rash and diarrhea. The g