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Cuccia F, Mazzola R, Nicosia L, Figlia V, Giaj-Levra N, Ricchetti F, Rigo M, Vitale C, Mantoan B, De Simone A, Sicignano G, Ruggieri R, Cavalleri S, Alongi F. Impact of hydrogel peri-rectal spacer insertion on prostate gland intra-fraction motion during 1.5 T MR-guided stereotactic body radiotherapy. Radiat Oncol 2020; 15:178. [PMID: 32698843 PMCID: PMC7376654 DOI: 10.1186/s13014-020-01622-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/15/2020] [Indexed: 12/12/2022] Open
Abstract
Background The assessment of organ motion is a crucial feature for prostate stereotactic body radiotherapy (SBRT). Rectal spacer may represent a helpful device in order to outdistance rectal wall from clinical target, but its impact on organ motion is still a matter of debate. MRI-Linac is a new frontier in radiation oncology as it allows a superior visualization of the real-time anatomy of the patient and the current highest level of adaptive radiotherapy. Methods We present data regarding a total of 100 fractions in 20 patients who underwent MRI-guided prostate SBRT for low-to-intermediate risk prostate cancer with or without spacer. Translational and rotational shifts were computed on the pre- and post-treatment MRI acquisitions referring to the delivery position for antero-posterior, latero-lateral and cranio-caudal direction, and assessed using the Mann-Whitney U-Test. Results All patients were treated with a five sessions schedule (35 Gy/5fx) using MRI-Linac for a median fraction treatment time of 50 min (range, 46–65). In the entire study sample, median rotational displacement was 0.1° in cranio-caudal, − 0.002° in latero-lateral and 0.01° in antero-posterior direction; median translational shift was 0.11 mm in cranio-caudal, − 0.24 mm in latero-lateral and − 0.22 mm in antero-posterior. A significant difference between spacer and no-spacer patients in terms of rotational shifts in the antero-posterior direction (p = 0.033) was observed; also for translational shifts a positive trend was detected in antero-posterior direction (p = 0.07), although with no statistical significance. We observed statistically significant differences in the pre-treatment planning phase in favor of the spacer cohort for several rectum dose constraints: rectum V32Gy < 5% (p = 0.001), V28 Gy < 10% (p = 0.001) and V18Gy < 35% (p = 0.039). Also for bladder V35 Gy < 1 cc, the use of spacer provided a dosimetric advantage compared to the no-spacer subpopulation (p = 0.04). Furthermore, PTV V33.2Gy > 95% was higher in the spacer cohort compared to the no-spacer one (p = 0.036). Conclusion In our experience, the application of rectal hydrogel spacer for prostate SBRT resulted in a significant impact on rotational antero-posterior shifts contributing to limit prostate intra-fraction motion. Further studies with larger sample size and longer follow-up are required to confirm this ideally favorable effect and to assess any potential impact on clinical outcomes.
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Affiliation(s)
- Francesco Cuccia
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy.
| | - Rosario Mazzola
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Luca Nicosia
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Vanessa Figlia
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Niccolò Giaj-Levra
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Francesco Ricchetti
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Michele Rigo
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Claudio Vitale
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Beatrice Mantoan
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Antonio De Simone
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Gianluisa Sicignano
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Ruggero Ruggieri
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Stefano Cavalleri
- Urology Division, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy
| | - Filippo Alongi
- Advanced Radiation Oncology Deparment, Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy.,University of Brescia, Brescia, Italy
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