Spacers in radiotherapy treatment of prostate cancer: Is reduction of toxicity cost-effective?

Vanneste, Ben; Pijls‐Johannesma, Madelon; Voorde, Lien Van De; Lin, Emile N.J.T. van; Beek, Kees van de; Loon, J. Van; Ramaekers, Bram

doi:10.1016/j.radonc.2015.01.005

Cited by 55 publications

(41 citation statements)

References 26 publications

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“…Strong positive correlations were found between early foci production ratios (relative to baseline) and late rectal toxicity. If this finding is validated in future clinical studies, this assay could have clinical utility as methods to reduce rectal dose using, for example, peri-rectal hydrogel spacers for patients with high levels of circulating DSBs at early time-points after seed implant [41]. …”

Section: Discussionmentioning

confidence: 99%

Prostate cancer treated with brachytherapy; an exploratory study of dose-dependent biomarkers and quality of life

et al. 2017

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BackgroundLow-dose-rate permanent prostate brachytherapy (PPB) is an attractive treatment option for patients with localised prostate cancer with excellent outcomes. As standard CT-based post-implant dosimetry often correlates poorly with late treatment-related toxicity, this exploratory (proof of concept) study was conducted to investigate correlations between radiation − induced DNA damage biomarker levels, and acute and late bowel, urinary, and sexual toxicity.MethodsTwelve patients treated with 125I PPB monotherapy (145Gy) for prostate cancer were included in this prospective study. Post-implant CT based dosimetry assessed the minimum dose encompassing 90% (D90%) of the whole prostate volume (global), sub-regions of the prostate (12 sectors) and the near maximum doses (D0.1cc, D2cc) for the rectum and bladder. Six blood samples were collected from each patient; pre-treatment, 1 h (h), 4 h, 24 h post-implant, at 4 weeks (w) and at 3 months (m). DNA double strand breaks were investigated by staining the blood samples with immunofluorescence antibodies to γH2AX and 53BP1 proteins (γH2AX/53BP1). Patient self-scored quality of life from the Expanded Prostate Cancer Index Composite (EPIC) were obtained at baseline, 1 m, 3 m, 6 m, 9 m, 1 year (y), 2y and 3y post-treatment. Spearman’s correlation coefficients were used to evaluate correlations between temporal changes in γH2AX/53BP1, dose and toxicity.ResultsThe minimum follow up was 2 years. Population mean prostate D90% was 144.6 ± 12.1 Gy and rectal near maximum dose D0.1cc = 153.0 ± 30.8 Gy and D2cc = 62.7 ± 12.1 Gy and for the bladder D0.1cc = 123.1 ± 27.0 Gy and D2cc = 70.9 ± 11.9 Gy. Changes in EPIC scores from baseline showed high positive correlation between acute toxicity and late toxicity for both urinary and bowel symptoms. Increased production of γH2AX/53BP1 at 24 h relative to baseline positively correlated with late bowel symptoms. Overall, no correlations were observed between dose metrics (prostate global or sector doses) and γH2AX/53BP1 foci counts.ConclusionsOur results show that a prompt increase in γH2AX/53BP1foci at 24 h post-implant relative to baseline may be a useful measure to assess elevated risk of late RT − related toxicities for PPB patients. A subsequent investigation recruiting a larger cohort of patients is warranted to verify our findings.Electronic supplementary materialThe online version of this article (doi:10.1186/s13014-017-0792-1) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Prostate cancer treated with brachytherapy; an exploratory study of dose-dependent biomarkers and quality of life

et al. 2017

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“…From our experience and also as noted from the literature, the biggest challenge in SABR is to meet bladder and rectal dose constraints. For each patient, a polyethylene glycol hydrogel spacer will be inserted under trans-rectal ultrasound guidance which will potentially lead to further rectal dose reduction [24, 25]. Simulation CT and MRI scans will then be acquired and fused for contouring.…”

Section: Discussionmentioning

confidence: 99%

Class solutions for SABR-VMAT for high-risk prostate cancer with and without elective nodal irradiation

et al. 2016

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BackgroundThe purpose of this study is to find the optimal planning settings for prostate SABR-VMAT for high-risk prostate cancer patients irradiated to prostate only (PO) or prostate and pelvic lymph nodes (PPLN).MethodsFor 10 patients, plans using 6MV flattened, flattening-filter-free (FFF) 6MV (6 F) and FFF 10MV (10 F) photon beams with full and partial arc arrangements were generated and compared. The prescribed dose was 40Gy to the prostate with 25Gy to the PLN in 5 fractions. Plans were then evaluated for PTV coverage, dose fall-off, and OAR doses. The number of monitor units and the treatment delivery times were also compared. Statistical differences were evaluated using a paired sample Wilcoxon signed rank test with a significance level of 0.05%.ResultsA total of 150 plans were generated for this study. Acceptable PO plans were obtained using single arcs, while two arcs were necessary for PPLN. All plans were highly conformal (CI ≥1.3 and CN ≥0.90) with no significant differences in the PTV dose coverage. 6MV plans required significantly longer treatment time and had higher dose spillage compared to FFF plans. Superior plans were obtained using 10 F 300° partial arcs for PO with the lowest rectal dose, dose spillage and the shortest treatment times. For PPLN, 6 F and 10 F plans were equivalent.ConclusionsSABR-VMAT with FFF photon beams offers a clear benefit with respect to shorter treatment delivery times and reduced dose spillage. Class solutions using a single 10 F 300° arc for PO and two 10 F or 6 F partial 300° arcs for PPLN are proposed.Electronic supplementary materialThe online version of this article (doi:10.1186/s13014-016-0730-7) contains supplementary material, which is available to authorized users.

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“…This is consistent with previously published results in the photon EBRT population, which have demonstrated a relative rectal dose reduction of 25% to 59% in patients who had PEG Hydrogel placed before therapy. [13][14][15] A median prostateerectum separation at midline of 10.5 mm on sagittal imaging was achieved in the hydrogel group and was positively correlated with dose reduction. A statistically significant association was not seen between dose reduction and length of separation on axial images.…”

Section: Discussionmentioning

confidence: 92%

Assessment of Polyethylene Glycol Hydrogel Spacer and Its Effect on Rectal Radiation Dose in Prostate Cancer Patients Receiving Proton Beam Radiation Therapy

Navaratnam

Cumsky

Abdul-Muhsin

et al. 2020

Advances in Radiation Oncology

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Purpose: To assess the efficacy of placing a polyethylene glycol (PEG) spacing hydrogel in patients undergoing proton beam radiation therapy for prostate cancer. This study also aims to assess the effect on rectal radiation dose of prostateerectum separation in various anatomic planes.Methods and Materials: Seventy-two consecutive prostate cancer patients undergoing conventionally fractionated pencil beam scanning proton radiation therapy with and without hydrogel placement were compared. Magnetic resonance images taken after hydrogel placement measured prostateerectum separation and were correlated to rectal dosing and rectal toxicity. Univariate analysis of clinical variables and radiation dosing was conducted using nonparametric Wilcoxon rank-sum test with continuity correction between groups (hydrogel spacer vs controls). Spearman's rank correlation coefficient assessed relationships between the various anatomic dimensions of perirectal space and rectal radiation dosing.Results: Fifty-one patients had hydrogel placement before therapy and 21 did not. There was a 42.2% reduction in rectal dosing (mL 3 rectum) in hydrogel patients (P < .001). Increasing midline sagittal lift resulted in a greater mitigation of total rectal dose (P Z .031). The degree of prostate surface area coverage on coronal plane did not correlate with further reductions in rectal radiation dose (P Z .673). Patients who had PEG hydrogels placed reported more rectal side effects during treatment compared with those patients who did not (35.3% vs 9.5%, P Z .061). At median 9.5-month follow-up, there was no difference in reporting of grade 2 rectal toxicity between the 2 groups (7.7% vs 7.1%, P Z .145).Conclusions: Polyethylene glycol hydrogel placement before pencil proton beam radiation therapy for prostate cancer reduced rectal radiation dose. The most important factor reducing total rectal dose was the degree of sagittal midline separation created by the PEG hydrogel. This is the largest study with the longest follow-up to investigate hydrogel placement in the proton beam radiation setting.

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Spacers in radiotherapy treatment of prostate cancer: Is reduction of toxicity cost-effective?

Abstract: IMRT+S is cost-effective compared to IMRT-O based on its potential to reduce radiotherapy-related toxicity.

Cited by 55 publications

References 26 publications

Prostate cancer treated with brachytherapy; an exploratory study of dose-dependent biomarkers and quality of life

Prostate cancer treated with brachytherapy; an exploratory study of dose-dependent biomarkers and quality of life

Class solutions for SABR-VMAT for high-risk prostate cancer with and without elective nodal irradiation

Assessment of Polyethylene Glycol Hydrogel Spacer and Its Effect on Rectal Radiation Dose in Prostate Cancer Patients Receiving Proton Beam Radiation Therapy

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