Treatment planning and delivery practice of lung SBRT: Results of the 2022 ESTRO physics survey.

BACKGROUND AND PURPOSE: The use of Stereotactic Body Radiation Therapy (SBRT) in lung cancer is increasing. However, there is no consensus on the most appropriate treatment planning and delivery practice for lung SBRT. To gauge the range of practice, quantify its variability and identify where consensus might be achieved, ESTRO surveyed the medical physics community. MATERIALS AND METHODS: An online survey was distributed to ESTRO's physicist membership in 2022, covering experience, dose and fractionation, target delineation, dose calculation and planning practice, imaging protocols, and quality assurance. RESULTS: Two-hundred and forty-four unique answers were collected after data cleaning. Most respondents were from Europe the majority of which had more than 5 years' experience in SBRT. The large majority of respondents deliver lung SBRT with the VMAT technique on C-arm Linear Accelerators (Linacs) employing daily pre-treatment CBCT imaging. A broad spectrum of fractionation schemes were reported, alongside an equally wide range of dose prescription protocols. A clear preference was noted for prescribing to 95% or greater of the PTV. Several issues emerged regarding the dose calculation algorithm: 22% did not state it while 24% neglected to specify the conditions under which the dose was calculated. Contouring was usually performed on Maximum or Average Intensity Projection images while dose was mainly computed on the latter. No clear indications emerged for plan homogeneity, complexity, and conformity assessment. Approximately 40% of the responders participated in inter-centre credentialing of SBRT in the last five years. Substantial differences emerged between high and low experience centres, with the latter employing less accurate algorithms and older equipment. CONCLUSION: The survey revealed an evident heterogeneity in numerous aspects of the clinical implementation of lung SBRT treatments. International guidelines and codes of practice might promote harmonisation.

Postoperative complications after esophagectomy for cancer, neoadjuvant chemoradiotherapy compared to neoadjuvant chemotherapy: A single institutional cohort study.

Background: Complications after esophagectomy are common and the possible increase in postoperative complications associated with neoadjuvant chemoradiotherapy is of concern. The aim of our study was to analyze if the addition of radiotherapy to neoadjuvant chemotherapy increases the incidence and severity of postoperative complications, including evaluation of the relation between radiation doses to the heart and lungs and postoperative complications. Methods: The study was based on an institutional surgical database for esophageal cancer. The study period was October 2008 to March 2020. Patients treated with neoadjuvant chemoradiotherapy were compared to patients treated with neoadjuvant chemotherapy and dose/volume parameters for the lungs and heart considered. The primary outcome was 30-day postoperative complications. Results: During the study period, 274 patients underwent surgery for esophageal cancer, 93 patients after neoadjuvant chemotherapy and 181 patients after neoadjuvant chemoradiotherapy. The median prescribed radiation dose to the planning target volume was 41.4 Gy, the median of the mean lung dose was 6.2 Gy, and the median of the mean heart dose was 20.3 Gy. The addition of radiotherapy to neoadjuvant chemotherapy did not increase the incidence of postoperative complications. Neither were radiation doses to the lungs and heart associated with postoperative complications. Taxane-based chemotherapy regimens were however associated with an increased incidence of postoperative complications. Conclusions: In our cohort, the addition of neoadjuvant radiotherapy to chemotherapy was not associated with postoperative complications. However, taxane-based chemotherapy regimens, with or without concomitant radiotherapy, were associated with postoperative complications.

Re-Irradiation for Head and Neck Cancer: Cumulative Dose to Organs at Risk and Late Side Effects.

Re-irradiation in head and neck cancer is challenging, and cumulative dose constraints and dose/volume data are scarce. In this study, we present dose/volume data for patients re-irradiated for head and neck cancer and explore the correlations of cumulative dose to organs at risk and severe side effects. We analyzed 54 patients re-irradiated for head and neck cancer between 2011 and 2017. Organs at risk were delineated and dose/volume data were collected from cumulative treatment plans of all included patients. Receiver-operator characteristics (ROC) analysis assessed the association between dose/volume parameters and the risk of toxicity. The ROC-curve for a logistic model of carotid blowout vs. maximum doses to the carotid arteries showed AUC = 0.92 (95% CI 0.83 to 1.00) and a cut-off value of 119 Gy (sensitivity 1.00/specificity 0.89). The near-maximum dose to bones showed an association with the risk of osteoradionecrosis: AUC = 0.74 (95% CI 0.52 to 0.95) and a cut-off value of 119 Gy (sensitivity 1.00/specificity 0.52). Our analysis showed an association between cumulative dose to organs at risk and the risk of developing osteoradionecrosis and carotid blowout, and our results support the existing dose constraint for the carotid arteries of 120 Gy. The confirmation of these dose-response relationships will contribute to further improvements of re-irradiation strategies.