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Background We recently published 2-year results of the prospective, randomized IMRT-MC2 trial, showing non-inferior local control and cosmesis in breast cancer patients after conventionally fractionated intensity-modulated radiotherapy with simultaneously integrated boost (IMRT-SIB), compared to 3D-conformal radiotherapy with sequential boost (3D-CRT-seqB). Here, we report on 2-year quality of life results. Patients and Methods 502 patients were enrolled and randomized to IMRT-SIB (50.4 Gy in 1.8 Gy fractions with a 64.4 Gy SIB to the tumor bed) or to 3D-CRT-seqB (50.4 Gy in 1.8 Gy fractions, followed by a sequential boost of 16 Gy in 2 Gy fractions). For quality of life (QoL) assessment, patients completed the QLQ-C30 and QLQ-BR23 questionnaires at baseline, 6 weeks and 2 years after radiotherapy. Results Significant differences between treatment arms were seen 6 weeks after radiotherapy for pain (22.3 points for IMRT vs. 27.0 points for 3D-CRT-seqB; p = 0.033) and arm symptoms (18.1 points for IMRT vs. 23.6 points for 3D-CRT-seqB; p = 0.013), both favoring IMRT-SIB. Compared to baseline values, both arms showed significant improvement in global score (IMRT: p = 0.009; 3D-CRT: p = 0.001) after 2 years, with slight deterioration on the role (IMRT: p = 0.008; 3-D-CRT: p = 0.001) and social functioning (IMRT: p = 0.013, 3D-CRT: p = 0.001) as well as the future perspectives scale (IMRT: p = 0.003; 3D-CRT: p = 0.0034). Conclusion This is the first randomized phase III trial demonstrating that IMRT-SIB was associated with slightly superior QoL compared to 3-D-CRT-seqB. These findings further support the clinical implementation of SIB in adjuvant breast cancer treatment.

Introduction External beam partial breast irradiation (PBI) provides equal oncological outcomes compared to whole breast irradiation when applied to patients with low risk tumours. Recently, linacs with an integrated magnetic resonance image-guidance system have become clinically available. Here we report the first-in-human PBI performed at the 1.5 T MR-Linac, with a focus on clinical feasibility and investigation of the air electron stream effect (ESE) and the electron return effect (ERE) in the presence of the 1.5 T magnetic field, which might influence the dose on the chin (out-of-field dose, due to the ESE), the skin and the lung/chest wall interface (in-field dose, ERE). Methods A 59 years old patient affected by a 15 mm unifocal grade 1 carcinoma not special type of the right breast staged pT1c pN0 cM0 was planned and treated at Unity 1.5 T MR-Linac. To investigate the ERE and the ESE, an MR-Linac treatment plan was simulated without considering the 1.5 T B field using a research version of Monaco (V. 5.19.03). In vivo dosimetry was performed using Gafchromic® EBT3 films placed on top and underneath a 1 cm bolus which was placed on the patient’s chin. The plans with and without 1.5 T magnetic field were compared in terms of dose to the chin, to the skin and to the interface lung/chest wall. Finally, the dose on the chin measured with the in vivo dosimetry was compared with the dose calculated by Monaco. Results PBI using the 1.5 T MR-Linac was successfully performed with a 7 MV photon 7-beams IMRT step-and-shoot plan. The treatment was well tolerated, the patient developed a slight acute toxicity, i.e. breast skin erythema and breast oedema CTC V.4 grade 1. The plan with 1.5 T magnetic field documented a fractional dose of 0.17 Gy in the chin area (2.6 Gy in 15 fractions), which was reduced to 0.05 Gy (0.75 in 15 fractions) by the presence of 1 cm bolus. The simulated plan without magnetic field showed a dose reduced by 2.3 Gy in the chin area. With the in vivo dosimetry a fractional dose of, respectively, 0.12 Gy and 0.034 Gy on top and underneath the bolus were measured (1.8 and 0.51 Gy in 15 fractions). The plan with 1.5 T magnetic field showed a skin D2 of 40 Gy and a skin V35 of 40.2%, which were reduced to, respectively, 39.7 Gy and 24.9% in the simulation without magnetic field. At the interface lung/chest there were no differences in DVH statistics. Conclusion PBI with the 1.5 T MR-Linac was performed for the first time. ESE is accurately calculated by the treatment planning system, can be effectively reduced with a 1 cm bolus and is comparable to dose of cone beam-CT based position verification. The additional dose caused by ERE is not associated with an increased risk of acute toxicity.

Background and purpose Outcome of patients with genitourinary rhabdomyosarcoma has been improved in the past, but organ preservation rates are too low. Conservative surgery with LDR-brachytherapy has been advocated, but LDR-brachytherapy is often not available. We wanted to establish a novel treatment modality combining HDR-brachytherapy and conservative surgery. Material and Methods We performed an organ preserving tumor resection with intraoperative placement of brachytherapy tubes. Suitable patients were selected following assessment of response to neoadjuvant chemotherapy where organ preserving surgical resection was deemed feasible. In bladder-prostate rhabdomyosarcoma, only tumors located below the bladder neck could be treated by brachytherapy. After surgery, high dose rate brachytherapy was carried out for 30–36Gy total dose. Results A total of 11 patients were treated up to now (embryonal histology n =10, alveolar histology n =1) with a median follow-up of 18months [4–80]. All patients were IRS group III. There were no significant side effects. One patient had local relapse and was successfully treated with re-excision. All other patients are in the first complete remission. One patient developed a neurogenic bladder and required creation of a Mitrofanoff stoma. Conclusion Combined conservative surgery and high dose rate brachytherapy is a treatment option for selected rhabdomyosarcoma patients. The paper highlights the essential technical challenges and clearly shows limitations of this treatment approach.