Surface-guided positioning eliminates the need for skin markers in radiotherapy of right sided breast cancer: A single center randomized crossover trial.

BACKGROUND AND PURPOSE: To prospectively investigate whether surface guided setup of right sided breast cancer patients can increase efficiency and accuracy compared to traditional skin marker/tattoo based setup. MATERIAL AND METHODS: Twenty-five patients were included in this study. Each patient was positioned using skin marks and tattoos (procedure A) for half of the fractions and surface guidance using AlignRT (procedure B) for the other half of the fractions. The order of the two procedures was randomized. Pretreatment CBCT was acquired at every fraction for both setup procedures. A total of ten time points were recorded during every treatment session. Applied couch shifts after CBCT match were recorded and used for potential error calculations if no CBCT had been used. RESULTS: In the vertical direction procedure B showed significant smaller population based systematic (Æ©) and random (σ) errors. However, a significant larger systematic error on the individual patient level (M) was also shown. This was found to be due to patient relaxation between setup and CBCT matching. Procedure B also showed a significant smaller random error in the lateral direction, while no significant differences were seen in the longitudinal direction. No significant difference in setup time was found between the two procedures. CONCLUSION: Setup of right sided breast cancer patients using surface guidance yields higher accuracy than setup using skin marks/tattoos and lasers with the same setup time. Patient alignment for this patient group can safely be done without the use of permanent tattoos and skin marks when utilizing surface-guided patient positioning. However, CBCT should still be used as final setup verification.

Improved adaptive radiotherapy to adjust for anatomical alterations during curative treatment for locally advanced lung cancer.

Anatomical changes during chemoradiation for lung cancer may decrease dose to the target or increase dose to organs at risk. To assess our ability to identify clinically significant anatomical alterations, we followed 67 lung cancer patients by daily cone-beam CT scans to ensure correct patient positioning and observe anatomical alterations. We also re-calculated the original dose distribution on a planned control CT scan obtained halfway during the treatment course to identify anatomical changes that potentially affected doses to the target or organs at risk. Of 66 patients who completed the treatment, 12 patients needed adaptation, two patients were adapted twice. We conclude that daily cone-beam CT and routines at the treatment machine discover relevant anatomical changes during curative radiotherapy for patients with lung cancer without additional imaging.

Use of radiotherapy in breast cancer patients with brain metastases: a retrospective 11-year single center study.

AIM: To analyse the use of radiotherapy (RT) and factors affecting overall survival (OS) after RT in breast cancer patients with brain metastases. METHODS: Breast cancer patients treated from 2008 to 2018 with whole brain RT (WBRT) or stereotactic radiosurgery (SRS) at a large regional cancer referral center were identified from the hospital's RT register. Clinical variables were extracted from medical records. OS was calculated from date of first RT until death or last follow up. Potential factors affecting OS were analyzed. RESULTS: 255 females with WBRT (n = 206) or SRS (n = 49) as first RT were included. An increased use of initial SRS was observed in the second half of the study period. The most common WBRT fractionation regimen was 3 Gy × 10. SRS was most often single fractions; 18 or 25 Gy between 2009 and 2016, while fractionated SRS was mostly used in 2017 and 2018. Median OS in the WBRT group was 6 months (CI 1-73) relative to 23 (CI 0-78) in the SRS group. Age, performance status, initial RT technique, extracranial disease, brain metastasis surgery, number of brain metastases and DS-GPA score had significant impact on OS. Only ECOG 0 and brain metastasis surgery were associated with superior OS in multivariate analysis. CONCLUSION: WBRT was the most frequent primary RT. An increased use of initial SRS was observed in the second half of the study period. Only ECOG 0 and brain metastasis surgery were associated with superior OS in multivariate analysis.

The prognostic role of 18F-fluorodeoxyglucose PET in head and neck cancer depends on HPV status.

BACKGROUND AND PURPOSE: Standardized uptake value (SUV) and related parameters derived from 2-deoxy-2-[18F]-fluoro-d-glucose (FDG) PET/CT prior to radiochemotherapy of head and neck cancer (HNC) were significantly associated with survival in a number of studies. The aim of this study was to validate these findings and to evaluate the prognostic role of PET parameters also including clinical factors and HPV status. MATERIALS AND METHODS: We reviewed 166 HNC cases with a radiotherapy planning FDG PET/CT scan. All patients received radiotherapy, 68-70 Gy with or without concomitant cisplatin. Primary endpoint was disease-free survival (DFS). Twelve clinical factors, including HPV, performance status, stage and treatment parameters and ten PET/CT image parameters including gross tumor volume (GTV), metastatic lymph node volume, SUVmax, metabolic tumor volume (MTV) and total lesion glycolysis (TLG), were collected. Univariate and multivariate Cox regression analyses were employed. RESULTS: Of the 166 patients included, 48 had locoregional and 23 had metastatic recurrence. None of the FDG PET parameters were significant in the univariate analysis using DFS as endpoint. HPV status, ECOG status and GTV-U (primary tumor and lymph node volume from CT) were statistically significant (p < 0.01). Only in the subgroup of HPV-unrelated HNC (HPV negative oropharyngeal cancer [OPC] and non-OPC; n = 73), the multivariate model could be improved by including MTV (p < 0.001). DFS events were 29 (31%) in HPV-related and 53 (73%) in HPV-unrelated HNC. CONCLUSION: FDG PET parameters appear less important for overall prognostication of radiochemotherapy outcome for HNC. Still, the association between the FDG PET parameters and survival is strong for HNC not related to HPV. Tumor volume from CT is generally more closely related to outcome than parameters derived from FDG PET/CT.

Validation of dose painting of lung tumours using alanine/EPR dosimetry.

Biologic image guided radiotherapy (RT) with escalated doses to tumour sub volumes challenges today's RT dose planning and delivery systems. In this phantom study, we verify the capability of a clinical dose planning and delivery system to deliver an 18F-FDG-PET based dose painted treatment plan to a lung tumour. Furthermore, we estimate the uncertainties of the dose painted treatment compared to conventional RT plans. An anthropomorphic thorax phantom of polystyrene and polyurethane was constructed based on CT images of a lung cancer patient. 101 EPR/alanine dosimeters were placed in separate cavities within the phantom. IMRT and VMAT plans were generated in Eclipse (version 10.0, Analytical Anisotropic Algorithm version 10.2.28, Varian Medical Systems, Inc.) for 6 and 15 MV photons, based on 18F-FDG-PET/CT images of the patient. A boost dose of 3.8 Gy/fraction was given to the 18F-FDG-avid region (biological planning volume; BTV), whereas 3.1 Gy/fraction was planned to the planning target volume (PTV, excluding the BTV). For the homogenous plans, 3.2 Gy/fraction was given to the PTV. Irradiation of the phantom was carried out at a Varian Trilogy linear accelerator (Varian Medical Systems, Inc.). Uncertainties involved in treatment planning and delivery were estimated from portal dosimetry gamma evaluation. Measured and calculated doses were compared by Bland-Altmann analysis. For all treatment plans, all dose-volume objectives could be achieved in the treatment planning system. The mean absolute differences between calculated and measured doses were small (<0.1 Gy) for BTV, PTV-BTV, lung and soft tissue. The estimated uncertainty of the planned doses was less than 3% for all plans, whereas the estimated uncertainty in the measured doses was less 2.3%. Our results show that planning and delivery of dose escalated lung cancer treatment on a clinical dose planning and delivery system has high dosimetric accuracy. The uncertainties associated with the dose escalated treatment plans are comparable to the conventional plans.