Volker Rudat

The goal of the study was to assess the impact of deep inspiration breath hold technique (DIBH), surface-guided radiotherapy (SGRT), and daily kilovoltage cone-beam computed tomography (kV-CBCT) on the dose to organs at risk (OAR) in left-sided breast cancer radiotherapy. Twenty-six consecutive left-sided breast cancer patients treated using Volumetric Intensity Modulated Arc Therapy (VMAT), DIBH, SGRT, and a hypofractionated regimen were retrospectively evaluated in this study. Dose parameters were extracted from dose-volume histograms (DVH). The Wilcoxon Matched Pairs test was used to test dose parameters obtained in free breathing (FB) and DIBH for statistical significance. Multivariable analysis of variance (ANOVA) and receiver operating characteristics (ROC) analysis were used to identify parameters and cut-off points associated with the reduction of the mean heart dose (MHD) by DIBH. Based on published models, the risk of cardiac and lung toxicity (pneumonitis) using SGRT or daily kV-CBCT was estimated and compared. DIBH substantially reduced the MHD (median, 43.6%; range, 4.2% to 75.1%; P < 0.00001). The risk of cardiac toxicity using SGRT increased by 1%, compared to 3.6% to 20.5% using daily kV-CBCT. No significant difference in the risk of radiation-induced pneumonitis using SGRT versus daily kV-CBCT was detected. The ANOVA revealed the relative increase of the left lung volume by DIBH as the only significant impact factor for the MHD. The ROC analysis of this parameter showed an area under the curve (AUC) of 0.89 (95%CI, 0.71 to 0.98; P < 0.0001). DIBH can substantially reduce the MHD in left-sided breast cancer patients treated with modern radiotherapy techniques and hypofractionation. Patient setup using SGRT compared to daily kV-CBCT may be the preferred option for many patients. In our patient cohort, the relative reduction of the left lung volume by DIBH can be used as a predictor to select patients who benefit from DIBH.

Purpose: The use of volumetric modulated arc therapy (VMAT), simultaneous integrated boost (SIB), and hypofractionated regimen requires adequate patient setup accuracy to achieve an optimal outcome. The purpose of this study was to assess the setup accuracy of patients receiving left‐sided breast cancer radiotherapy using deep inspiration breath‐hold technique (DIBH) and surface guided radiotherapy (SGRT) and to calculate the corresponding setup margins.Methods: The patient setup accuracy between and within radiotherapy fractions was measured by comparing the 6DOF shifts made by the SGRT system AlignRT with the shifts made by kV‐CBCT. Three hundred and three radiotherapy fractions of 23 left‐sided breast cancer patients using DIBH and SGRT were used for the analysis. All patients received pre‐treatment DIBH training and visual feedback during DIBH. An analysis of variance (ANOVA) was used to test patient setup differences for statistical significance. The corresponding setup margins were calculated using the van Herk's formula.Results: The intrafractional patient setup accuracy was significantly better than the interfractional setup accuracy (p < 0.001). The setup margin for the combined inter‐ and intrafractional setup error was 4, 6, and 4 mm in the lateral, longitudinal, and vertical directions if based on SGRT alone. The intrafractional error contributed ≤1 mm to the calculated setup margins.Conclusion: With SGRT, excellent intrafractional and acceptable interfractional patient setup accuracy can be achieved for the radiotherapy of left‐sided breast cancer using DIBH and modern radiation techniques. This allows for reducing the frequency of kV‐CBCTs, thereby saving treatment time and radiation exposure.

The goal of the study was to evaluate the inter- and intrafractional patient setup accuracy of target volumes located in the head, thoracic, abdominal, and pelvic regions when using SGRT, by comparing it with that of laser alignment using patient skin marks, and to calculate the corresponding setup margins. A total of 2303 radiotherapy fractions of 183 patients were analyzed. All patients received daily kilovoltage cone-beam computed tomography scans (kV-CBCT) for online verification. From November 2019 until September 2020, patient setup was performed using laser alignment with patient skin marks, and since October 2020, using SGRT. The setup accuracy was measured by the six degrees of freedom (6DOF) corrections based on the kV-CBCT. The corresponding setup margins were calculated using the van Herk formula. Analysis of variance (ANOVA) was used to evaluate the impact of multiple factors on the setup accuracy. The inter-fractional patient setup accuracy was significantly better using SGRT compared to laser alignment with skin marks. The mean three-dimensional vector of the translational setup deviation of tumors located in the thorax, abdomen, and pelvis using SGRT was 3.6 mm (95% confidence interval (CI) 3.3 mm to 3.9 mm) and 4.5 mm using laser alignment with skin marks (95% CI 3.9 mm to 5.2 mm; p = 0.001). Calculation of setup margins for the combined inter- and intra-fractional setup error revealed similar setup margins using SGRT and kV-CBCT once a week compared to laser alignment with skin marks and kV-CBCT every other day. Furthermore, comparable setup margins were found for open-face thermoplastic masks with AlignRT compared to closed-face thermoplastic masks with laser alignment and mask marks. SGRT opens the possibility to reduce the number of CBCTs while maintaining sufficient setup accuracy. The advantage is a reduction of imaging dose and overall treatment time. Open-face thermoplastic masks may be used instead of closed-face thermoplastic masks to increase the patient's comfort.

Purpose To estimate the long-term effect of low-dose radiotherapy of painful plantar calcaneal spurs, and to verify possible prognostic factors. Patients and methods In this retrospective unicenter study, electronic patient files of patients with painful plantar calcaneal spurs treated with low-dose radiotherapy between July 2009 and February 2020 were reviewed. The low-dose radiotherapy consisted of a total dose of 3.0 Gy given with a fraction dose of 0.5 Gy three times a week. The pain reduction was estimated using a patient questionnaire with a visual analogue scale. Kaplan–Meier statistics and Cox regression analysis were used for the statistical analysis. Results Altogether, 864 heels of 666 patients were reviewed. The probability of an insufficient pain control 10 years after low-dose radiotherapy was 45.9% (95% confidence interval 39.4–52.4%) in the subset of patients with a minimum follow-up of 3 months (582 heels of 467 patients). Patients with an unsatisfactory pain reduction 3 months after low-dose radiotherapy were offered a re-irradiation. Forty percent of the patients who received a re-irradiation developed good pain reduction. Occurrence of an initial aggravation of pain during or within 3 months after low-dose radiotherapy (p = 0.005), and treatment of bilateral painful plantar calcaneal spurs (p = 0.008) were identified as significant unfavorable prognostic factors on univariate analysis. On multivariate analysis, the initial aggravation of pain remained as independent significant prognostic factor (p = 0.01). No clear radiation toxicity was observed. Conclusions Low-dose radiotherapy is a safe and effective treatment option for patients with painful plantar calcaneal spurs. An initial aggravation of pain during or within 3 months after radiotherapy was identified as unfavorable prognostic factor for the treatment outcome. Re-irradiation of patients with an unsatisfactory pain reduction after low-dose radiotherapy is effective and should be offered to patients.

This study provides separate comparisons of 1 × 8 Gy to 5 × 4 Gy for metastatic epidural spinal cord compression (MESCC) in patients with poor, intermediate and favorable survival prognoses. Patients receiving 1 × 8 Gy were matched to patients receiving 5 × 4 Gy for age, gender, performance status, tumor type, involved vertebrae, other bone metastases, visceral metastases, interval between tumor diagnosis and MESCC, ambulatory status and time developing motor deficits. From a study including patients with poor (N = 156) or intermediate (N = 86) survival prognoses, subgroup analyses were performed. Furthermore, 232 new patients with favorable prognoses matched the same way were included. In poor prognoses patients, 6-month survival rates were 10% after 1 × 8 Gy and 6% after 5 × 4 Gy (p = 0.38); in-field reRT rates in few patients alive at 6 months were 15 and 2% (p = 0.16). In intermediate prognoses patients, 6-month survival rates were 49% after 1 × 8 Gy and 58% after 5 × 4 Gy (p = 0.30). ReRT rates at 6 months were 23 and 13% (p = 0.25). In favorable prognoses patients, 6-month survival rates were 89% after 1 × 8 Gy and 91% after 5 × 4 Gy. ReRT rates at 6 months were 14 and 3% (p = 0.007). In no subgroup, RT regimen had a significant impact on motor function. Since in patients with poor prognoses, outcomes after 1 × 8 Gy and 5 × 4 Gy were not significantly different, 1 × 8 Gy may be an option. In patients with intermediate prognoses, a trend was found in favor of 5 × 4 Gy. In patients with favorable prognoses, need for in-field reRT was greater after 1 × 8 Gy.

Background/Aim: According to our randomized trial, 5×4Gy was comparable to 10×3Gy for metastatic spinal cord compression. Since it remained unclear whether findings applied to poor and intermediate prognoses patients, subgroup analyses were performed. Patients and Methods: In patients with poor prognoses, 58 received 5×4Gy, 53 received 10×3Gy. In intermediate-prognoses patients, numbers were 43 and 49. Results: In patients with poor prognoses, 1-month overall response (OR) was 85% after 5×4Gy and 10×3Gy (p=0.99), improvement 38% vs. 42%, ambulatory status 60% vs. 64% (p=0.83), 6-month local progression-free survival (LPFS) 75% vs. 69% (p=0.74) and 6-month overall survival (OS) 26% vs. 19% (p=0.43). In patients with intermediate prognoses, 1-month OR was 89% after 5×4Gy and 93% after 10×3Gy (p=0.85), improvement 39% vs. 45%, ambulatory status 84% vs. 82% (p=0.90), 6-month LPFS 79% vs. 92% (p=0.17) and 6-months OS 65% vs. 58% (p=0.65). Conclusion: 5×4Gy was not significantly inferior to 10x3Gy in both subgroups.

The aim of the study was to identify factors significantly associated with the occurrence of unintended treatment interruptions in adjuvant breast cancer radiotherapy.

Introduction: Radiotherapy alone still is the most commonly delivered treatment modality for metastatic spinal cord compression (MSCC). MSCC is an emergency situation, which requires treatment as soon as possible. When radiotherapy is performed with the most commonly used approach 10 × 3 Gy (30 Gy in 10 fractions) over 2 weeks, the question has been asked whether an overall treatment time (OTT) of 14–15 days including two weekends without irradiation leads to worse outcomes than OTT of 12 days (beginning of radiotherapy on a Monday resulting in only one weekend break)?Methods: A total of 412 patients with MSCC were included in this retrospective study. Ninety‐two patients receiving 10 × 3 Gy over 12 days were compared to 320 patients with an OTT of 14–15 days. Ten additional factors were investigated.Results: On multivariate analysis, functional outcome was associated with tumour type (P < 0.001), time developing motor deficits (P < 0.001), ambulatory status (P = 0.018) and performance score (P < 0.001); OTT had no significant impact (P = 0.40). On univariate analysis of local control of MSCC (freedom from recurrence in irradiated spinal parts), no factor was significant including OTT (P = 0.66). On multivariate analysis, visceral metastases (P < 0.001), tumour type (P < 0.001), time developing motor deficits (P < 0.001), ambulatory status (P < 0.001) and performance score (P < 0.001) were associated with survival, OTT not even on univariate analysis (P = 0.55).Conclusions: Since an OTT of 14–15 days had no negative impact on outcomes compared to 12 days, compensation in form of an additional radiation fraction or continuation of radiotherapy during weekends is not required, if radiotherapy cannot be started on a Monday.

The purpose of the study was to evaluate the impact of multiple prognostic factors on the acute skin reaction in adjuvant breast cancer radiotherapy, in particular the impact of hypofractionation (HF) compared to conventional fractionation (CF) and tangential beam (TB) IMRT compared to three-dimensional conformal radiotherapy (3DCRT). Two-hundred and sixty-six breast cancer patients with postoperative radiotherapy after breast conserving surgery or mastectomy were retrospectively evaluated. Patients were treated with HF (15 fractions of 2.67 Gy; n = 121) or CF (28 fractions of 1.8 Gy or 25 fractions of 2.0 Gy; n = 145) and TB-IMRT (n = 151) or 3DCRT (n = 115). The acute skin reactions were prospectively assessed using the CTCAE v4 grading scale. Ordinal regression analysis was used to assess the impact of possible prognostic factors on the maximal acute skin reaction. Grade 2 skin reactions were observed in 19 % of the patients treated with CF compared to 2 % treated with HF. On univariate analysis, the fractionation regimen, the PTV (breast versus chest wall), the volume of the PTV and the body mass index were significant prognostic factors for the maximum acute skin reaction. On multivariate analysis, the fractionation regimen (p < 0.00001) and the volume of the PTV (p = 0.0002) remained as independent significant factors. Our data suggest that HF is associated with a significantly reduced maximal acute skin reaction compared to CF.