Quantification of Acute Skin Toxicities in Patients With Breast Cancer Undergoing Adjuvant Proton versus Photon Radiation Therapy: A Single Institutional Experience

DeCesaris, C.; Rice, Stephanie R.; Bentzen, Søren M.; Jatczak, J.; Mishra, Mark V.; Nichols, Elizabeth M.

doi:10.1016/j.ijrobp.2019.04.015

Cited by 52 publications

(57 citation statements)

References 22 publications

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“…Adjuvant PBT after BCS has been reported in the literature in mostly small retrospective cohorts (Table 3). 5,[10][11][12][13] Our reported rates of AEs compare favorably to the literature.…”

Section: Discussionsupporting

confidence: 80%

Acute toxicities after proton beam therapy following breast‐conserving surgery for breast cancer: Multi‐institutional prospective PCG registry analysis

et al. 2020

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Radiotherapy (RT) after breast-conserving surgery (BCS) for breast cancer improves breast cancer mortality and decreases recurrence. 1 However, the benefit of adjuvant breast RT is partially offset by nonbreast morbidity caused by dose to normal structures, including the heart. 2 Various techniques and technologies are used to minimize the dose to surrounding normal structures including deep inspiration breath-hold, intensity-modulated radiation therapy, and proton beam therapy (PBT). 3 Adjuvant whole-breast RT can be delivered with photons or PBT. PBT offers unique dosimetric advantages, such as improved target and internal mammary nodal (IMN) coverage, 4,5 decreased lung dose, 6,7 and decreased heart dose. 6,7 However, PBT has some disadvantages including decreased patient access, 8 increased cost, 9 and higher rates of acute radiation dermatitis (RD). 10 We report a prospectively evaluated multi-institutional cohort of patients who received adjuvant whole-breast PBT after BCS for breast cancer. 2 | ME THODS The Proton Collaborative Group (PCG) REG001-09 trial is an IRBapproved, multi-institutional prospective registry of patients treated with PBT. Between 2012 and 2016, 82 patients underwent BCS followed by PBT to the whole breast at seven participating institutions.

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Section: Discussionsupporting

confidence: 80%

Acute toxicities after proton beam therapy following breast‐conserving surgery for breast cancer: Multi‐institutional prospective PCG registry analysis

et al. 2020

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“…From a clinical point of view, the quantification of skin dose in proton therapy can be used to relate absorbed dose and skin toxicity. As the current study provides a dosimetric link to skin studies with other beam qualities, the assessment of possible skin reactions at the stage of proton therapy treatment planning can be improved . We note, however, that the granularity of the dose grid in the treatment planning systems, which concerns the source model data and the dose grid on the patient model, does not allow for a direct implementation of the depth dose curves of the current work.…”

Section: Discussionmentioning

confidence: 99%

“…One advantage of proton therapy is the favorable depth dose distribution facilitating optimal treatment target volume coverage while reducing the absorbed dose in the surrounding organs at risk. One clinical study shows a higher skin toxicity in proton compared to photon irradiation that could be related to a higher skin dose . However, quantification of the surface dose within the first few hundred µm is challenging and not well investigated yet.…”

Section: Introductionmentioning

confidence: 99%

Determination of surface dose in pencil beam scanning proton therapy

et al. 2020

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Purpose/objective Quantification of surface dose within the first few hundred water equivalent µm is challenging. Nevertheless, it is of large interest for the proton therapy community to study dose effects in the skin. The experimental determination is affected by the detector properties, such as the detector volume and material. The International Commission on Radiation Units and Measurements in its report 39 recommends assessing the skin dose at a depth of 0.07 mm. The aim of this study is the estimation of the absorbed dose at and around a depth of 70 µm. We used various dosimetric approaches in conjunction with proton pencil beam scanning delivery to determine the skin dose in a clinical setting. Material/methods Five different detectors were tested for determining the surface dose in water: EBT3 and HD‐V2 GAFCHROMIC™ radiochromic film, LiF:Mg,Ti thermoluminescent dosimeter, IBA PPC05 plane‐parallel ionization chamber, and PTW 23391 extrapolation chamber. The irradiation setup consisted of quasi‐monoenergetic scanned proton pencil beams with kinetic energies of 100, 150, and 226.7 MeV, respectively. Radiochromic films were placed within a vertical stack and in wedge geometry and were analyzed with FilmQA Pro™ adopting triple channel dosimetry. The extrapolation chamber PTW 23391, which served as a reference in the current work, was used in a conventional ionization chamber setup with a fixed electrode gap of 2 mm. Three Kapton® entrance windows with thicknesses of 25, 50, and 75 µm were employed. Thermoluminescent dosimeters were provided as powder and were pressed onto a sheet of aluminum. Furthermore, the Monte Carlo code TOol for PArticle Simulation (TOPAS) in version 3.1.p2 was used to model an IBA pencil beam scanning nozzle and score dose to water in a water phantom. Results The resulting depth dose curves were normalized to their 100% dose at the reference depth of 3 cm. We obtained the skin doses with the extrapolation chamber and with TOPAS. For the experimental approach this resulted in 79.7 ± 0.3%, 86.0 ± 0.6%, and 87.1 ± 0.1% for the proton energies 100, 150, and 226.7 MeV, respectively. The results for TOPAS were 80.1 ± 0.2% (100 MeV), 87.1 ± 0.5% (150 MeV), and 86.9 ± 0.4% (226.7 MeV), respectively. Based on the experimental results of the skin dose, we provided a clinically relevant surface extrapolation factor for the common measurement methods. This allows the result of the first measurement depth of a detector to be scaled to the dose at the skin depth. Most practical would be the use of the surface extrapolation factor for the PPC05 chamber, due to its direct reading, the wide availability in clinics and the low uncertainties. The calculated factors were 0.986 ± 0.004 for 100 MeV, 0.961 ± 0.008 for 150 MeV, and 0.963 ± 0.003 for 226.7 MeV. Conclusions In this study, dissimilar experimental approaches were evaluated with respect to measurements at depths close to the surface. The experimental depth dose curves are in good agreement with the simulation with TOPAS Monte Carlo. To the author's...

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“…Interestingly, in their study, the authors found a greater rate of G2 RD in the proton therapy group, but no difference in the rate of G3 RD between proton and IMRT. Recently, De Cesaris et al (11) reported on RD after treatment of 86 breast cancer patients undergoing adjuvant proton or photon RT. They observed an increase in moderate (G2) toxicity associated to proton therapy; again, no significant difference between treatment modalities was found for severe RD.…”

Section: Discussionmentioning

confidence: 99%

“…However, the risk of a potential increase of skin toxicity has long been considered a peculiar drawback in the clinical use of protons. The higher beam entry dose of the spread-out Bragg peak represents a disadvantage for the skin; thus causing concern over a possible increase in skin adverse effects (10,11).…”

Section: Introductionmentioning

confidence: 99%

NTCP Models for Severe Radiation Induced Dermatitis After IMRT or Proton Therapy for Thoracic Cancer Patients

et al. 2020

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Radiation therapy (RT) of thoracic cancers may cause severe radiation dermatitis (RD), which impacts on the quality of a patient's life. Aim of this study was to analyze the incidence of acute RD and develop normal tissue complication probability (NTCP) models for severe RD in thoracic cancer patients treated with Intensity-Modulated RT (IMRT) or Passive Scattering Proton Therapy (PSPT). We analyzed 166 Non-Small-Cell Lung Cancer (NSCLC) patients prospectively treated at a single institution with IMRT (103 patients) or PSPT (63 patients). All patients were treated to a prescribed dose of 60 to 74 Gy in conventional daily fractionation with concurrent chemotherapy. RD was scored according to CTCAE v3 scoring system. For each patient, the epidermis structure (skin) was automatically defined by an in house developed segmentation algorithm. The absolute dose-surface histogram (DSH) of the skin were extracted and normalized using the Body Surface Area (BSA) index as scaling factor. Patient and treatment-related characteristics were analyzed. The Lyman-Kutcher-Burman (LKB) NTCP model recast for DSH and the multivariable logistic model were adopted. Models were internally validated by Leave-One-Out method. Model performance was evaluated by the area under the receiver operator characteristic curve, and calibration plot parameters. Fifteen of 166 (9%) patients developed severe dermatitis (grade 3). RT technique did not impact RD incidence. Total gross tumor volume (GTV) size was the only non dosimetric variable significantly correlated with severe RD (p = 0.027). Multivariable logistic modeling resulted in a single variable model including S 20Gy , the relative skin surface receiving more than 20 Gy (OR = 31.4). The cut off for S 20Gy was 1.1% of the BSA. LKB model parameters were TD 50 = 9.5 Gy, m = 0.24, n = 0.62. Both NTCP models showed comparably high prediction and calibration performances. Despite skin toxicity has long been considered a potential limiting factor in the clinical use of PSPT, no significant differences in RD incidence was found between RT modalities. Once externally validated, the availability of NTCP models for prediction of severe RD may advance treatment planning optimization.

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Quantification of Acute Skin Toxicities in Patients With Breast Cancer Undergoing Adjuvant Proton versus Photon Radiation Therapy: A Single Institutional Experience

Cited by 52 publications

References 22 publications

Acute toxicities after proton beam therapy following breast‐conserving surgery for breast cancer: Multi‐institutional prospective PCG registry analysis

Acute toxicities after proton beam therapy following breast‐conserving surgery for breast cancer: Multi‐institutional prospective PCG registry analysis

Determination of surface dose in pencil beam scanning proton therapy

NTCP Models for Severe Radiation Induced Dermatitis After IMRT or Proton Therapy for Thoracic Cancer Patients

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