Volumetric-modulated arc stereotactic body radiotherapy for prostate cancer: dosimetric impact of an increased near-maximum target dose and of a rectal spacer

Ruggieri, R.; Naccarato, S.; Stavrev, Pavel; Stavreva, N; Fersino, S.; Levra, Niccolò Giaj; Mazzola, Rosario; Mancosu, P.; Scorsetti, Marta; Alongi, Filippo

doi:10.1259/bjr.20140736

Cited by 39 publications

(33 citation statements)

References 18 publications

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“…By considering that less than 1 cm3 of the PTV overlapping the rectum, bladder, and urethral planning-risk-volume (i.e., 3 mm isotropic expansion from the urethra) had to receive Dp, no less than 95% Dp (33.2 Gy) had to be assured to 95% of the PTVminus-any-overlap with the rectum, bladder, or urethral PRV. However, 98% of any of such three overlapping volumes needed to receive at least 32 Gy [6].…”

Section: T Mr-guided Radiotherapymentioning

confidence: 99%

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1.5 T MR-guided and daily adapted SBRT for prostate cancer: feasibility, preliminary clinical tolerability, quality of life and patient-reported outcomes during treatment

et al. 2020

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Background: Unity Elekta is a unique magnetic resonance (MR)-linac that conjugates a 1.5 Tesla MR unit with a 7 MV flattening filter free accelerator.A prospective observational study for the clinical use of Elekta Unity is currently ongoing in our department. Herein, we present our preliminary report on the feasibility, quality of life, and patientreported outcomes measures (PROMs) for localized prostate cancer (PC) treated with stereotactic body radiotherapy (SBRT). Methods: The SBRT protocol consisted of a 35 Gy schedule delivered in 5 fractions within 2 weeks. Toxicity and quality of life (QoL) were assessed at baseline and after treatment using the Common Terminology Criteria for Adverse Events v5.0, International Prostatic Symptoms Score (IPSS), ICIQ-SF, IIEF-5, and EORTC-QLQ-C30 and PR-25 questionnaires. Results: Between October 2019 and January 2020, 25 patients with localized PC were recruited. The median age was 68 years (range, 54-82); 4 were low risk, 11 favorable intermediate risk (IR) and 10 unfavorable IR. Median iPSA was 6.8 ng/ml (range, 1-19), and 9 of these patients (36%) received concurrent androgen deprivation therapy. Median prostate volume was 36 cc (range, 20-61); median baseline IPSS was 5 (range, 0-10). Median time for fraction was 53 min (range, 34-86); adaptive strategy with daily critical structure and target re-contouring and daily replanning (adapt to shape) was performed in all cases. No grade ≥ 3 adverse event was observed, three patients (12%) reported grade 2 acute genitourinary toxicity (urinary frequency, urinary tract pain and urinary retention), while only one patient reported mild rectal pain. No relevant deteriorations were reported in PROMs.

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Section: T Mr-guided Radiotherapymentioning

confidence: 99%

“…Clinical experiences in PC RT by means of intensitymodulated and image-guided techniques (IMRT-IGRT) have demonstrated a lower probability of RT-related adverse events [4][5][6]. These RT-technological and technical advances have allowed clinicians to deliver higher radiation doses to the target with similarly limited toxicities.…”

Section: Introductionmentioning

confidence: 99%

1.5 T MR-guided and daily adapted SBRT for prostate cancer: feasibility, preliminary clinical tolerability, quality of life and patient-reported outcomes during treatment

et al. 2020

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“…By considering that less than 1 cm3 of the PTV overlapping the rectum, bladder, and urethral planning-risk-volume (i.e., 3mm isotropic expansion from the urethra) had to receive Dp, no less than 95% Dp (33.2 Gy) had to be assured to 95% of the PTV-minus-any-overlap with the rectum, bladder, or urethral PRV. However, 98% of any of such three overlapping volumes needed to receive at least 32 Gy [6].…”

Section: T Mr-guided Radiotherapymentioning

confidence: 99%

“…Clinical experiences in PC RT by means of intensity-modulated and image-guided techniques (IMRT-IGRT) have demonstrated a lower probability of RT-related adverse events [4][5][6]. These RTtechnological and technical advances have allowed clinicians to deliver higher radiation doses to the target with similarly limited toxicities.…”

Section: Introductionmentioning

confidence: 99%

1.5T MR-guided and daily adapted SBRT for prostate cancer: feasibility, preliminary clinical tolerability, quality of life and patient-reported outcomes during treatment

Alongi

Rigo

Figlia

et al. 2020

Preprint

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Background Unity Elekta is a unique magnetic resonance (MR)-linac that conjugates a 1.5 Tesla MR unit with a 7 MV flattening filter free accelerator.A prospective observational study for the clinical use of Elekta Unity is currently ongoing in our department. Herein, we present our preliminary report on the feasibility, quality of life, and patient-reported outcomes measures (PROMs) for localized prostate cancer (PC) treated with stereotactic body radiotherapy (SBRT). Methods The SBRT protocol consisted of a 35 Gy schedule delivered in 5 fractions within two weeks. Toxicity and quality of life (QoL) were assessed at baseline and after treatment using the Common Terminology Criteria for Adverse Events v5.0, International Prostatic Symptoms Score (IPSS), ICIQ-SF, IIEF-5, and EORTC-QLQ-C30 and PR-25 questionnaires. Results Between October 2019 and January 2020, 25 patients with localized PC were recruited. The median age was 68 years (range, 54-82); 4 were low risk, 11 favorable intermediate risk (IR) and 10 unfavorable IR. Median iPSA was 6.8 ng/ml (range, 1-19), and 9 of these patients (36%) received concurrent androgen deprivation therapy. Median prostate volume was 36 cc (range, 20-61); median baseline IPSS was 5 (range, 0-10). Median time for fraction was 53 minutes (range, 34-86); adaptive strategy with daily critical structure and target re-contouring and daily replanning (adapt to shape) was performed in all cases. No grade ≥ 3 adverse event was observed, three patients (12%) reported grade 2 acute genitourinary toxicity (urinary frequency, urinary tract pain and urinary retention), while only one patient reported mild rectal pain. No relevant deteriorations were reported in PROMs. Conclusion To the best of our knowledge, this is the first experience reporting feasibility, clinician-reported outcome measurements, and PROMs for 1.5T MR-guided adaptive SBRT for localized prostate cancer. The preliminary data collected here report optimal safety and excellent tolerability, as also confirmed by PROMs questionnaires. Moreover, the data on technical feasibility and timing of online daily adapted planning and delivery are promising. More mature data are warranted.

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“…Dose‐escalated external beam radiation therapy (EBRT) (≥ 78 Gy) has replaced the previous standard dose of ~70 Gy as the new “standard of care” for the treatment of prostate cancer 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12. Dose‐escalated EBRT significantly improves biochemical progression‐free survival in most patients, and also overall survival in patients with intermediate‐ or high‐risk disease 7, 13, 14.…”

Section: Introductionmentioning

confidence: 99%

Rectal dose to prostate cancer patients treated with proton therapy with or without rectal spacer

Chung

Polf

Badiyan

et al. 2016

J Applied Clin Med Phys

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The purpose of this study was to evaluate whether a spacer inserted in the prerectal space could reduce modeled rectal dose and toxicity rates for patients with prostate cancer treated in silico with pencil beam scanning (PBS) proton therapy. A total of 20 patients were included in this study who received photon therapy (12 with rectal spacer (DuraSeal™ gel) and 8 without). Two PBS treatment plans were retrospectively created for each patient using the following beam arrangements: (1) lateral‐opposed (LAT) fields and (2) left and right anterior oblique (LAO/RAO) fields. Dose volume histograms (DVH) were generated for the prostate, rectum, bladder, and right and left femoral heads. The normal tissue complication probability (NTCP) for ≥grade 2 rectal toxicity was calculated using the Lyman–Kutcher–Burman model and compared between patients with and without the rectal spacer. A significantly lower mean rectal DVH was achieved in patients with rectal spacer compared to those without. For LAT plans, the mean rectal V70 with and without rectal spacer was 4.19 and 13.5%, respectively. For LAO/RAO plans, the mean rectal V70 with and without rectal spacer was 5.07 and 13.5%, respectively. No significant differences were found in any rectal dosimetric parameters between the LAT and the LAO/RAO plans generated with the rectal spacers. We found that ≥ 9 mm space resulted in a significant decrease in NTCP modeled for ≥grade 2 rectal toxicity. Rectal spacers can significantly decrease modeled rectal dose and predicted ≥grade 2 rectal toxicity in prostate cancer patients treated in silico with PBS. A minimum of 9 mm separation between the prostate and anterior rectal wall yields the largest benefit.

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Volumetric-modulated arc stereotactic body radiotherapy for prostate cancer: dosimetric impact of an increased near-maximum target dose and of a rectal spacer

Abstract: For VMAT plans in prostate SBRT, the distinct dosimetric usefulness of increased D2% and of the use of spacer insertion were validated in terms of target coverage and rectal sparing.

Cited by 39 publications

References 18 publications

1.5 T MR-guided and daily adapted SBRT for prostate cancer: feasibility, preliminary clinical tolerability, quality of life and patient-reported outcomes during treatment

1.5 T MR-guided and daily adapted SBRT for prostate cancer: feasibility, preliminary clinical tolerability, quality of life and patient-reported outcomes during treatment

1.5T MR-guided and daily adapted SBRT for prostate cancer: feasibility, preliminary clinical tolerability, quality of life and patient-reported outcomes during treatment

Rectal dose to prostate cancer patients treated with proton therapy with or without rectal spacer

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