Objective: The main aim of the current analysis was to explore the hypothetical advantages using rectal spacer during 1.5T MR-guided and daily adapted prostate cancer stereotactic body radiotherapy (SBRT) compared to a no-rectal spacer hydrogel cohort of patients. Methods: The SBRT-protocol consisted of a 35 Gy schedule delivered in 5 fractions. Herein, we present a dosimetric analysis between spacer and no-spacer patients. Furthermore, treatment tolerability and feasibility were preliminarily assessed according to clinicians-reported outcomes at the end of treatment and patient-reported outcomes measures (PROMs) in both arms. Toxicity and quality of life were assessed at baseline and after treatment using the Common Terminology Criteria for Adverse Events v. 5.0, International Prostatic Symptoms Score, ICIQ-SF, IIEF-5, and EORTC-QLQ-C30 and PR-25 questionnaires. Results: 120 plans (pre- and daily adaptive SBRT planning) were analyzed in 20 patients (10 patients in spacer group and 10 patients in no-spacer group) treated using 1.5T MR-guided adaptive SBRT. Statistically significant dosimetric advantages were observed in favor of the spacer insertion, improving the planning target volume coverage in terms of V33.2Gy >95% and planning target volume 37.5 Gy <2% mainly during daily-adapted SBRT. Also, rectum V32, V28 and V18Gy and bladder V35Gy <1 cc were significantly reduced in the spacer cohort. Concerning the PROMS, all questionnaires showed no difference between the pre- and post-SBRT evaluation in both arms, excepting the physical functioning item of EORTC QLQ-C30 questionnaire that was declined in the no-spacer group. Conclusion: These preliminary results strongly suggest the adoption of perirectal spacer due to dosimetric advantages not only for rectal sparing but also for target coverage. Longer follow-up is required to validate the clinical impact in terms of clinicians-reported toxicity and PROMs. Advances in knowledge: This the first experience reporting preliminary data concerning the potential dosimetric impact of rectal hydrogel spacer on MR-guided SBRT for prostate cancer.

Purpose: The present study reports the preliminary outcomes in terms of adverse events and quality of life in the first 100 patients treated with 1.5T MR-guided daily-adaptive stereotactic body radiotherapy for prostate cancer. Methods: From October 2019 to December 2020, 100 patients, enrolled in a prospective study, received MR-guided SBRT for prostate cancer. Rectal spacer insertion was optional and administered in 37 patients. In total, 32 patients received androgen deprivation therapy in accordance with international guidelines. A prospective collection of data regarding toxicity and quality of life was performed. Results: The median age was 71 years (range, 52–84). The median total dose delivered was 35 Gy (35–36.25 Gy) in five sessions, either on alternate days (n = 25) or consecutive days (n = 75). For acute toxicity, we recorded: seven cases of acute G2 urinary pain and four cases of G2 gastrointestinal events. The median follow-up was 12 months (3–20), recording three late G2 urinary events and one G3 case, consisting of a patient who required a TURP 8 months after the treatment. For gastrointestinal toxicity, we observed 3 G ≥ 2 GI events, including one patient who received argon laser therapy for radiation-induced proctitis. Up to the last follow-up, all patients are alive and with no evidence of biochemical relapse, except for an M1 low-volume patient in distant progression two months after radiotherapy. QoL evaluation reported a substantial resolution of any discomfort within the second follow-up after radiotherapy, with the only exception being sexual items. Notably, after one year, global health items were improved compared to the baseline assessment. Conclusions: This study reports very promising outcomes in terms of adverse events and QoL, supporting the role of 1.5T MR-guided SBRT for prostate cancer. To date, this series is one of the first and largest available in the literature. Long-term results are warranted.

Objectives: MR-guided daily-adaptive radiotherapy is improving the accuracy in the planning and delivery phases of the treatment. Rectal hydrogel-spacer may help in mitigating organ motion, but few data are currently available. Methods: We aimed to assess any potential impact of the device on seminal vesicles motion by measuring translational and rotational shifts between the pre- and post-treatment MRI scans of a total of 50 fractions in the first 10 patients who underwent MR-guided prostate SBRT (35 Gy/5 fx). Of them, five patients received the hydrogel-spacer. The comparative analysis was performed using the Mann–Whitney U-test Results: Median rotational shifts were: in anteroposterior 0° (range, 0.097°/0.112°; SD = 0.05°) vs 0° (−0.162/0.04°; SD = 0.07°) in the no-spacer subgroup (p = 0.36); lateral shifts were 0° (−0.1°/0.54°; SD = 0.28°) vs −0.85° in the no-spacer cohort (−1.56°/0.124°; SD = 0.054°; p = 0.22). Cranio-caudal shifts were 0° (−0.121°/0.029°; SD = 0.06°) in the spacer-cohort vs 0° (−0.066°/0.087°; SD = 0.69°; p = 0.53). Median translational shifts were: in anteroposterior 0.9 mm (−0.014 mm/0.031 mm; SD = 0.036 mm) in the spacer-group vs 0.030 mm (−0.14 mm/0.03 mm; SD = 0.032 mm; p = 0.8); latero-lateral shifts were −0.042 mm (−0.047 mm/0.07 mm; SD = 0.054 mm), vs −0.023 mm (−0.027 mm/−0.01 mm; SD = 0.023 mm) in the no-spacer group (p = 0.94). In cranio-caudal, statistically significant shifts were reported: 0.082 mm (0.06 mm/0.15 mm; SD = 0.04 mm) vs 0.06 mm (−0.06/0.08 mm; SD = 0.09 mm) in the no-spacer cohort (p = 0.031). Conclusions: A favorable impact of the hydrogel-spacer on seminal vesicles motion was observed only in cranio-caudal translational shifts, although being not clinically significant. Further studies are required to fully investigate the potential contribution of this device on vesicles motion. Advances in knowledge: MR-guided daily adaptive radiotherapy may represent a game changer for prostate stereotactic body radiotherapy, given the possibility to better visualize soft-tissues anatomy and to daily recalculate the treatment plan based on real-time conditions. The use of devices like rectal ballon or rectal gel spacers has gained interest in the last years for the possibility to better spare the rectum during prostate radiotherapy. This is one of the first experiences exploring the role of rectal spacer on seminal vesicles intrafraction motion during MR-guided SBRT for prostate cancer.

Lung toxicity in patients undergoing cetuximab and radiotherapy (Cetux-RT) for head and neck squamous cell carcinoma (HNSCC) has been reported in literature and represents a serious side effect of concurrent therapies. We report a case of a HNSCC patient that developed neck emphysema during the course of Cetux-RT. The patient was an old male (80 years old) in a good performance status, with an oropharyngeal cancer (T4aN3a). During RT, cone-beam computed tomography (CBCT) showed bilateral neck emphysema that was confirmed at restaging CT. We decided to stop the treatment and to treat the neck emphysema with conservative strategies. After one week CT was repeated and the neck emphysema had improved, so we decided to complete the RT treatment. Patients undergoing Cetux-RT must be properly selected, whereas IGRT imaging must be viewed carefully in order to permit an early diagnosis and careful management of the patients.