Partial Breast Brachytherapy Research Articles

PP05 Presentation Time: 4:06 PM: Introducing a Robotic 3D Ultrasound System for Improved Seroma Visualization and Implant Guidance in Partial Breast Brachytherapy

PP05 Presentation Time: 4:06 PM: Introducing a Robotic 3D Ultrasound System for Improved Seroma Visualization and Implant Guidance in Partial Breast Brachytherapy

PO121: Accelerated Partial Breast Brachytherapy in the Setting of Invasive Lobular Carcinoma

PO121: Accelerated Partial Breast Brachytherapy in the Setting of Invasive Lobular Carcinoma

Abstract P1-10-11: Optical stimulated luminescence dosimeters for skin dose measurements during accelerated partial breast brachytherapy: In vivo dosimetric validation and clinical outcomes

Abstract BACKGROUND: The role of multi-lumen catheter devices in the delivery of high dose rate (HDR) brachytherapy for adjuvant accelerated partial breast irradiation (APBI) for women with DCIS or early-stage breast cancer has been well established. In vivo dosimetry (IVD) using optically stimulating luminescence dosimeters (OSLD) is a feasible way to detect applicator instability that may cause translational and rotational inaccuracies during HDR brachytherapy delivery. Herein, we evaluate the accuracy and effectiveness of IVD to improve patient outcomes following APBI brachytherapy using the Strut Adjusted Volume Irradiation (SAVI) device. METHODS: Single-institution cohort study piloting the use of OSLD on the patient’s skin during HDR brachytherapy APBI to assess the estimated maximum skin dose (skin Dmax) and the achievable accuracy of OSLD for skin Dmax measurements. Women treated with SAVI-based APBI between November 1, 2018 and October 1, 2021 were eligible to enroll in our study. All patients met the American Society for Radiation Oncology “suitable” or “cautionary” criteria and were treated according to the American Brachytherapy Society consensus treatment planning guidelines. A SAVI preplan was created to estimate the probable point of skin Dmax. During CT simulation, a radiopaque marker was placed on the skin for visualization during treatment planning. Correction factors were applied to account for the OSLD tissue-air interface that is not present in the TG-43 expected dose calculations. Measured and calculated IVD doses were analyzed to assess agreement and cause for discrepancies found. Breast phantom IVD measurements repeated seven times with two independent dose points were analyzed to assess the best accuracy achievable under ideal conditions. RESULTS: We enrolled 41 patients with an average age of 68 years. Table 1 details the brachytherapy treatment delivery and dosimetry data. Higher skin Dmax as a percentage of the radiation prescription was associated with the occurrence of breast volume loss noted on subsequent clinical breast exams (OR 1.84 per each 5% increase in skin Dmax; 95% CI 1.21 – 3.32; p=0.016). The graphically estimated skin Dmax threshold was 80% with all cases of noted breast volume loss occurring above this threshold. The overall level of achievable IVD accuracy was ±3.32% based on breast phantom measurements. Under ideal conditions, all measurements were in the ±7% range. Three of 14 phantom measurement exceeded the 6% discrepancy range. Clinical IVD measurements detected 5 true positive cases (12.2% of cohort) that required intervention due to rotations in the SAVI applicator. For a ±7% tolerance criteria, 90.2% of the patients tested passed IVD. Of the eight patients that failed at the 7% level, IVD detected 3 OSLD placement errors, 2 rotational discrepancy cases, and 1 large air-gap at the point of measurement. CONCLUSIONS: Accuracy and reproducibility are imperative tenets of HDR brachytherapy APBI. IVD utilizing OSLD is an effective method for detecting treatment set-up and delivery errors for patients receiving SAVI-based APBI with dose accuracy within ±3.32%. Errors requiring intervention due to SAVI device rotation were detected in 12.2% of our cohort, and these errors would have likely gone undetected without IVD. Using OSLD as IVD to measure skin Dmax doses that may increase the risk of breast cosmetic defects should be investigated further. Table 1. Brachytherapy treatment delivery and dosimetry data. *PTV-Eval is a uniform 10 mm expansion on the CTV with exclusion of PTV within 5 mm of skin or chest wall. +Percent dose discrepancy refers to difference in dose between APBI plan calculations and IVD measurements. Citation Format: Tyler Gutschenritter, Afua Yorke, Nayak Polissar, Nirnaya Miljacic, Janice Kim, Lori Young. Optical stimulated luminescence dosimeters for skin dose measurements during accelerated partial breast brachytherapy: In vivo dosimetric validation and clinical outcomes [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-10-11.

Accelerated brachytherapy with the Xoft electronic source used in association with iodine, gold, bismuth, gadolinium, and hafnium nano-radioenhancers

PurposeThe current study was designed to calculate the dose enhancement factor (DEF) of iodine (I), gold (Au), bismuth (Bi), gadolinium (Gd), and hafnium (Hf) nanoparticles (NP)s by Monte Carlo (MC) modeling of an electronic brachytherapy source in resection cavities of breast tumors. Methods and materialsThe GEANT4 MC code was used for simulation of a phantom containing a water-filled balloon and a Xoft source (50 kVp) to irradiate the margins of a resected breast tumor. NPs with a diameter of 20 nm and concentrations from 1 to 5% w/w were simulated in a tumor margin with 5 mm thickness as well as a hypothetical breast model consisting of spherical island-like residual tumor-remnants. The DEFs for all NPs were calculated in both models. ResultsIn the margin-loaded model, for the concentration of 1% w/w heavy atom, DEFs of 2.5, 2.3, 2.1, 2, and 1.7 were calculated for Bi, Au, I, Hf, and Gd NPs (descending order), which increased, almost linearly with concentration for all NPs. Moreover, normal tissue dose behind the NP-loaded margin declined significantly depending on NP type and concentration. When modeling residual tumor islands, DEF values were very close to the margin-loaded values except for Bi and I, where DEFs of 2.55 and 1.7 were seen, respectively. ConclusionsConsiderable dose enhancements were obtained for the heavy atom NPs studied in the partial breast brachytherapy with a Xoft electronic source. In addition, normal tissue doses were lowered in the points beyond the NP-loaded margin. The findings revealed promising outcomes and the probability of improved tumor control for NP-aided brachytherapy with the Xoft electronic source.

Computed tomography-guided partial-breast brachytherapy using implanted catheters as fiducial markers versus co-registered magnetic resonance imaging

Partial-breast irradiation (PBI) needs accurate cavity delineation with computed tomography (CT). In perioperative PBI using multicatheter-interstitial brachytherapy (MIB), catheters implanted during surgery were enabled as fiducial markers. Magnetic resonance imaging (MRI) can also assist delineation with CT. Patients receiving MIB-PBI were analyzed. Cavity visualization scores (CVSs) were categorized with CT. With catheter-based delineation (CBD), the relationship between cavity boundaries and catheters were used to contour the tumor bed. Co-registered MRI delineation (CMD) was also performed. The correlation between cavity volume and the excised tissue weight was compared for the two techniques. The association between CVS and preoperative characteristics in 159 patients showed mammographic breast density (MBD) remained correlated to CVS on multiple regression analyses; CVS = 5.2-0.61 x MBD (p < 0.0001). In 43 patients, the cavity volumes determined with CBD vs CMD were 12.8 ± 6.4 cm3 vs 16.1 ± 12.4 cm3 (p < 0.0001), and their plots with excised weights showed the best fitting lines were 0.29 vs 0.48 (p < 0.0001), respectively. The correlation coefficients for CBD vs CMD were 0.65 vs 0.55 (p = 0.20) in low (CVS 1-3, n = 27) and 0.72 vs 0.58 (p = 0.36) in high visualized cavities (CVS 4-5, n = 16), respectively. The use of implanted catheters as fiducial markers was associated with smaller cavities and greater correlations with the excised tissue weights than co-registration with MRI. This might be a useful technique, especially for patients with dense breasts on mammography.

Patient-reported quality of life with interstitial partial breast brachytherapy and external beam whole breast radiotherapy: a comparison using propensity-score matching.

PurposeThe aim of this study was to compare patient-reported quality of life (QOL) scores after accelerated partial breast irradiation (APBI) using interstitial brachytherapy vs. external beam whole breast radiotherapy (WBRT) for breast cancer.Material and methodsWomen with breast cancer treated with WBRT or APBI after breast conservation surgery were enrolled in this prospective study. Single cross-sectional QOL assessment was performed using EORTC QLQ-C30 and BR-23 questionnaires. Patients treated with APBI were propensity-score matched to similar cohort of patients treated with WBRT. QOL scores were analyzed for the entire unmatched cohort and compared between the two matched cohorts using Student’s two-tailed t-test. P-value of < 0.05 was considered statistically significant, and a 10-point difference between mean scores was considered clinically meaningful.ResultsA total of 64 APBI patients were matched with 99 WBRT patients out of the entire study cohort of 320 cases. QOL scores for functional scales of QLQ-C30 were similar between the two groups for both matched and unmatched cohorts, while symptom scores of QLQ-C30 did not show any clinically significant difference. Functional scales of BR-23 did not show any clinical or statistically significant difference. Among symptom scales of BR-23, scores were similar for APBI and WBRT groups except for a worse score of “upset by hair loss” sub-scale in the brachytherapy group of the matched cohort (51.9 vs. 22.7, p = 0.006).ConclusionsPatients undergoing APBI reported similar QOL compared to WBRT when matched for various factors.

Optimization of the accelerated partial breast brachytherapy fractionation considering radiation effect on planning target and organs at risk

The same fractionation scheme of accelerated partial breast irradiation (APBI) with brachytherapy is usually applied to APBI patients without considering the radiaton effect on the planning target and organs at risk (OARs) for an individual patient. The purpose of this study is to report the results of optimization of the fractionation scheme by evaluating the radiation effect on target and OARs with a modified linear-quadratic model, universal survival curve (USC), based on dose-volume histograms (DVHs). Ten breast patients treated with multilumen balloon brachytherapy were selected. The minimum skin and chest wall/rib (CW/rib) spacing ranged from 2.5 to 14.3 mm and from 0.5 to 25.0 mm, respectively. The USC model parameters were set as: (1) breast:α = 0.3, β = 0.05; (2) skin: acute reaction α = 0.101, β = 0.009; late reaction α = 0.064, β = 0.029; (3) CW/rib: α = 0.3, β = 0.12. Boundary dose Dt was 6 Gy for both target and OARs. The relation between radiation effects on the target (ET) and OARs (EOAR) were plotted for fraction numbers (N) from 1 to 20. If ET is set at a certain value, the fractionation that results in a minimum EOAR value corresponds to the optimal fractionation. The results show that the optimal fractionation is different for different OAR damage effects. For most of the patients, N = 2 is best for minimizing skin acute reactions while N = 20 is best for minimizing skin late reactions. N varies from 3 to 20 among patients for minimizing CW/rib toxicity. The determined unique optimal N for treatment delivery was found to vary from 1 to 20 among these 10 patients resulted from balancing the different damage effects considering the spatial dose for a given patient geometry. Optimal fractionation can be achieved for an individual patient by evaluating the radiation effect on tumor and OARs with the USC model based on the patient specific DVHs with APBI brachytherapy.

Efficacy of Single-Plane Implant Technique in Partial Breast Brachytherapy in Small-Breasted Patients

Partial-breast irradiation (PBI) using multicatheter-interstitial brachytherapy (MIB) has been supported by some randomized trials to date. However, it remains underused in Asian countries because of the population's typically smaller breasts. Single-plane implantation has been recommended in these individuals, but limited data on the clinical efficacy exist. We performed a retrospective chart review to compare the tumor control and long-term cosmesis in patients treated with the single-plane implant technique. Patients receiving MIB-PBI between October 2008 and December 2018 were evaluated. PBI was initiated on the same day of the surgery via an intraoperative catheter implant, delivering 32 Gy by 8 fractions. Tumor control based on the rate of freedom from ipsilateral tumor recurrence (IBTR), disease-free survival, and long-term cosmesis using the Harvard scale was evaluated to compare between the single- and double-/triple-plane implant techniques. Five hundred sixteen patients with 526 lesions received MIB-PBI with a median follow-up of 53.1 months. Patients treated by single- and double- or triple-plane implant numbered 288 (54.8%) and 238 (45.2%), respectively. The 4-year probabilities of IBTR-free survival and disease-free survival were 97.5% and 96.5% in single-plane implant and 98.6% (P = .42) and 98.0% (P = .18) in double- or triple-plane implant MIB-PBI, respectively. Although young age (P < .05) and positive surgical margins (P < .01) were selected as independent risk factors for IBTR, single-plane implantation was not recognized as a risk factor of IBTR. Sixty-one of 69 single-plane implant patients (88.4%) and 84 of 92 double-/triple-plane implant patients (91.3%) reported excellent to good cosmetic results (P = .73). Although this was a retrospective study from a single institution and cosmesis was evaluated using a subjective method, this is the first report to validate single-plane implant MIB-PBI for use in small-breasted patients. Further multicenter research is required.

Three-Fraction Intracavitary Accelerated Partial Breast Brachytherapy: Early Provider and Patient-Reported Outcomes of a Novel Regimen

To report early adverse events and patient-reported outcomes (PROs) of 3-fraction intracavitary catheter-based partial breast brachytherapy (ICBB). Eligible women ≥50years of age with ≤2.5-cm, lymph node-negative invasive or in situ breast cancer underwent breast-conserving surgery and placement of a brachytherapy applicator. ICBB was initiated on the second weekday after surgery and prescribed to 21Gy in 3 once-daily fractions. Common Terminology Criteria for Adverse Events, version 4.0; 10-point linear analog scale assessment; the PRO version of the Common Terminology Criteria for Adverse Events; and the Harvard Breast Cosmesis Scale were used for provider and patient-reported assessments. Seventy-three women were treated for invasive (79%) or in situ (21%) breast cancer. The median time to completion of surgery and radiation therapy was 6days. After 14-months median follow-up, 2 patients (3%) had developed breast infections that resolved with oral antibiotics. There was no other treatment-associated adverse event grade ≥2. The grade 1 seroma rate at 3months was 20%, which dropped to 8% at 12months; no events required intervention. At 12months, 91% of patients reported an overall quality of life score as ≥8 of 10, and patient-reported cosmesis was good or excellent in 95%. All patients are alive without relapse at the last follow-up. Three-fraction ICBB is associated with low rates of early provider and patient- reported adverse events and compares favorably with early outcomes of more protracted ICBB regimens, including twice-daily (3.4Gy×10) fractionation studied in the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-39. Further investigation is warranted.

Prospective Study of 3-Fraction Intra-Cavitary Accelerated Partial Breast Brachytherapy: Early Provider and Patient-Reported Outcomes of a Novel Regimen

The optimal dose and fractionation for accelerated partial breast irradiation (APBI) is not known. We evaluated 3-fraction brachytherapy APBI in the context of a prospective clinical trial. Our purpose is to report early adverse effects and patient-reported outcomes (PROs) of this novel regimen. Eligible women were ≥ 50 years of age with ≤2 cm estrogen receptor positive, sentinel lymph node (SLN) negative invasive or in-situ breast cancer treated with breast conserving surgery. After frozen section pathology assessment of negative surgical margins and SLN(s), a multi-channel intra-cavitary brachytherapy catheter was placed intraoperatively. APBI was initiated on the second weekday after surgery after permanent section pathology confirmation. The prescription was 21 Gy in 3, once daily, fractions targeting the lumpectomy cavity with a 1 cm expansion. Common toxicity criteria for adverse effects (CTCAE v 4.0), 10-point linear analog scales, PROs version of the CTCAE (PRO-CTCAE), and Harvard Breast Cosmesis Scale (HBCS) were utilized for provider and patient-reported assessments. Seventy-three women, median age 66 years, were treated for invasive breast cancer (79%) or ductal carcinoma in situ (21%) between 2015 and 2017. Tumor grade was 1-2 in 88%. The median time to completion of all locoregional therapy (surgery and radiotherapy) was 6 days. After 14 months median follow-up, two patients (3%) had developed breast infections that resolved with oral antibiotics. There was no other treatment-associated adverse effects ≥ grade 2. The grade 1 seroma rate at 3 months was 20% (11/56 evaluable patients) which dropped to 8% (4/49) at 12 months; none required intervention. PROs are summarized in table 1. At 12 months, 91% reported overall QOL between 8 and 10 and patient-reported cosmesis was good or excellent in 95%. All patients were alive without relapse at the last follow-up. The 3-fraction, once daily, breast brachytherapy was associated with favorable early physician and PROs. These early results compare favorably with other reports including the more universally employed twice daily (3.4 Gy x 10) fractionation being studied in NSABP B-39. A randomized trial comparing these two approaches is warranted.Abstract TU_5_3369; Table 1Patient-Reported Outcomes associated with 3-fraction brachytherapy APBIPROsLASA 10Baseline (n=56)Post-RT (n=51)3 month (n=44)6 month (n=46)12 month (n=35)Quality of Lifeα8-1095%96%89%96%91%4-74%2%7%2%9%1-31%2%4%2%0%Breast CosmesisExcellent55%41%50%65%69%Good45%49%39%26%26%Fair0%10%9%9%6%Poor0%0%2%0%0%Painβ0-361%69%86%91%86%4-632%22%7%4%9%7-107%10%7%4%6%Fatigueβ0-361%55%75%63%71%4-625%37%16%24%12%7-1014%8%9%13%17%Skin BurnsNone100%90%88%96%100%Mild0%8%12%2%0%Moderate0%0%0%0%0%Severe0%0%0%0%0%Very Severe0%2%0%2%0%LASAα: Reported on a scale of 1-10 (1 indicating “worst” and 10 indicating “best”) LASAβ: Reported on a scale of 1-10 (1 indicating “none” and 10 indicating “as bad as it can be”). Open table in a new tab

Dosimetric feasibility of an anthropomorphic three-dimensional PRESAGE® dosimeter for verification of single entry hybrid catheter accelerated partial breast brachytherapy

AbstractPurposeTo determine the feasibility of an anthropomorphic breast polyurethane-based three-dimensional (3D) dosimeter with cavity to measure dose distributions and skin dose for a commercial strut-based applicator strut-adjusted volume implant (SAVI™) 6–1.Materials and methodsAn anthropomorphic breast 3D dosimeter was created with a cavity to accommodate the SAVI™ strut-based device. 2 Gy was prescribed to the breast dosimeter having D95 to planning target volume evaluation (PTV_EVAL) while limiting 125% of the prescribed dose to the skin. Independent dose distribution verification was performed with GAFCHROMIC® EBT2 film. The dose distribution from the 3D dosimeter was compared to the distributions from commercial brachytherapy treatment planning system (TPS) and film. Point skin doses, line profiles and dose–volume histogram (DVHs) for the skin and PTV_EVAL were compared.ResultsThe maximum difference in skin dose for TPS and the 3D dosimeter was 4% whereas 41% between the TPS and EBT2 film. The maximum dose difference for line profiles between TPS, 3D dosimeter, and film was 4·1%. DVHs of skin and PTV_EVAL for TPS and 3D dosimeter differed by a maximum of 4% at 5 mm depth and skin differed by a maximum 1·5% between TPS and 3D dosimeter. The criterion for gamma analysis comparison was 92·5% at ±5%±3 mm criterion. The TPS demonstrated at least ±5% comparability in predicting dose to the skin, PTV_EVAL and normal breast tissue.Conclusions3D anthropomorphic polyurethane dosimeter with cavity gives comparable results to the TPS dose predictions and GAFCHROMIC® EBT2 film results in the context of HDR brachytherapy.

Impact of inter-observer variations in target volume delineation on dose volume indices for accelerated partial breast irradiation with multi-catheter interstitial brachytherapy

PurposeTo investigate dosimetric impact of inter-observer variation in clinical target volume(CTV) delineation for patients undergoing interstitial partial breast brachytherapy. MethodsFive radiation oncologists delineated CTV in twenty patients who underwent multi-catheter partial breast brachytherapy. Five treatment plans for each patient were graphically optimized for CTV of all observers and evaluated using coverage index(CI), external volume index(EI), overdose volume index(OI) and conformal index(COIN). In addition, volume enclosed by prescription isodose(V100), its spatial concordance(CIcommon), mean coverage of all CTVs with common volume of prescription dose(V100_common) and mean CTV coverage for all pairs of observer with common prescription volume of respective pairs(V100_pair) were also computed. ResultsThe mean ± standard deviation(SD) of CI and COIN ranged from 0.756 ± 0.076 to 0.840 ± 0.070 and 0.591 ± 0.090 to 0.673 ± 0.06 respectively. When a plan made for CTV of individual observer was evaluated on CTV of all observers, the maximum variations(ρ < 0.05) in the mean CI,COIN,OI and EI were 10.6%,11.4%,10.6% and 72.7% respectively. The observed mean ± SD of V100, CIcommon of V100, CTV coverage with V100_common and V100_pair was 160.7 ± 52.1, 0.70 ± 0.09, 73.1 ± 8.1% and 77.9 ± 7.3% respectively. ConclusionInter-observer variation in delineation of CTV showed significant dosimetric impact with mean CTV coverage of 73.1% and 77.9% by common and paired prescription dose volume respectively among all observers.

Validating the efficacy of single-stage breast-conserving therapy using multicatheter partial-breast brachytherapy based on updated ASTRO guidelines.

Based on the accumulating evidence for equivalent results of partial-breast irradiation (PBI) and whole-breast irradiation (WBI) in breast-conserving therapy (BCT), the American Society for Radiation Oncology (ASTRO) updated the consensus statement (CS) to expand the range of potential candidates for PBI outside clinical trials. Of the various techniques, PBI using multicatheter interstitial brachytherapy (MCB) is the oldest and has long-term data. In this study, the efficacy of single-stage BCT using MCB-PBI achieved by an intraoperative catheter placement was validated on updated ASTRO guidelines. We retrospectively examined patients undergoing BCT using MCB-PBI or WBI. The updated CS distinguished patients aged 40–49 years with ER+, tumor ≤2 cm, and margin ≥2 mm from unsuitable patients in the previous CS. We compared the ipsilateral breast tumor recurrence (IBTR) rate in MCB-PBI with that in WBI patients with suitable or cautionary (S/C) categories on the updated CS. Between November 2007 and September 2017, 641 patients with 647 lesions underwent BCT (MCB-PBI, 407; WBI, 240). At the median follow-up time of 54.4 months, we observed 8 (1.97%; 95% CI: 0.62–3.31%) and 7 (2.92%; 95% CI: 0.79–5.05%) IBTRs, respectively. Updating the CS increased the S/C patients receiving MCB-PBI from 232 patients (57.0%) to 319 (78.4%). Comparison of clinical outcomes at the 12-month minimum follow-up between 291 MCB-PBI and 103 WBI in S/C patients showed no significant differences in the 4-year rate of IBTR-free (100% vs 98.9%; P = 0.29) and disease-free survival (98.7% vs 95.5%; P = 0.24). Overall, single-stage BCT using MCB-PBI offered similar tumor control rates, compared with WBI, on the updated ASTRO CS.

Patient-reported outcomes of catheter-based accelerated partial breast brachytherapy and whole breast irradiation, a single institution experience.

Accelerated partial breast irradiation (APBI) and whole breast irradiation (WBI) are treatment options for early-stage breast cancer. The purpose of this study was to compare patient-reported-outcomes (PRO) between patients receiving multi-channel intra-cavitary brachytherapy APBI or WBI. Between 2012 and 2015, 131 patients with ductal carcinoma in situ (DCIS) or early stage invasive breast cancer were treated with adjuvant APBI (64) or WBI (67) and participated in a PRO questionnaire. The linear analog scale assessment (LASA), harvard breast cosmesis scale (HBCS), PRO-common terminology criteria for adverse events- PRO (PRO-CTCAE), and breast cancer treatment outcome scale (BCTOS) were used to assess quality of life (QoL), pain, fatigue, aesthetic and functional status, and breast cosmesis. Comparisons of PROs were performed using t-tests, Wilcoxon rank-sum, Chi square, Fisher exact test, and regression methods. Median follow-up from completion of radiotherapy and questionnaire completion was 13.3months. There was no significant difference in QoL, pain, or fatigue severity, as assessed by the LASA, between treatment groups (p>0.05). No factors were found to be predictive of overall QoL on regression analysis. BCTOS health-related QoL scores were similar between treatment groups (p=0.52).The majority of APBI and WBI patients reported excellent/good breast cosmesis, 88.5% versus 93.7% (p=0.37). Skin color change (p=0.011) and breast elevation (p=0.01) relative to baseline were more common in the group receiving WBI. APBI and WBI were both associated with favorable patient-reported outcomes in early follow-up. APBI resulted in a lesser degree of patient-reported skin color change and breast elevation relative to baseline.

Catheter-Based Accelerated Partial Breast Brachytherapy Results in Excellent Patient-Reported Quality of Life

Accelerated partial breast irradiation (APBI) and whole breast radiotherapy (WBR) are treatment options for early stage breast cancer. The purpose of this study was to compare patient-reported-outcomes (PRO) between patients receiving APBI or WBR. 197 chronologically matched patients (pts) with low risk, early stage breast cancer were treated with either APBI or WBR between October 2012 and May 2015. The Linear Analog 10-point Scales (LASA), Breast Cancer Treatment Outcome Scale (BCTOS), and Harvard Breast Cosmesis Scale (HBCS) were used to assess overall quality of life (LASA), pain (LASA, BCTOS), fatigue (LASA), perceived aesthetic and functional status (BCTOS, LASA), and breast cosmesis (BCTOS, HBCS). Comparisons of PROs between treatment groups were performed using Fisher exact test, chi-square, Wilcoxon rank-sum, and regression methods. Survey compliance was 66% (64 APBI and 67 WBR pts). Median follow-up was 13.3 months, with a mean interval between the last fraction and survey completion of 15.4 v 14.2 months (p=0.58), for the APBI and WBR groups, respectively. The majority of respondents had grade 1-2 (86%), T1 (92%), and N0 (93%) in-situ or invasive ductal carcinoma. Pts treated with WBR were more likely to be younger (median 65 v 69 yrs, p=0.02), have T2 tumors (15% v 2%, p=0.01), and to receive chemotherapy (21% v 2%, p<0.001). In the WBR group, the median dose delivered was 42.56 Gy in 16 fractions, with 54% of pts receiving a lumpectomy cavity boost (median dose 10 Gy). In the APBI group, the median dose delivered was 34 Gy in 10 twice daily fractions utilizing an intraoperatively-placed high dose rate brachytherapy applicator. There was no difference in overall quality of life (8.5 v 8.9, p=0.14), pain (2.1 v 2.1, p=0.21) or fatigue (3.0 v 3.0, p=0.21) between the APBI and WBR groups, respectively. The mean overall BCTOS (31.6 v 34.3, p=0.52) was similar between groups, as was the BCTOS overall cosmetic status, and individual cosmetic measures including breast size, nipple appearance, breast shape, and breast heaviness (all p>0.05). Individual BCTOS functional measures, including arm heaviness, breast/arm swelling, arm/shoulder range of motion, and joint stiffness were similar between groups, all p>0.05. A higher proportion of pts receiving WBR reported breast elevation (slight: 33% v 16%, moderate: 25% v 8%, p=0.01). Skin color change relative to baseline was also more common in the WBR group (p=0.01), with a trend towards greater telangiectasia formation (p=0.053). For the APBI and WBR groups, most pts reported excellent (48% v 54%) or good (41 v 40%) cosmesis, with no difference between groups (p=0.37). APBI and WBR are associated with excellent and comparable 1-year PROs. In this sample, APBI resulted in a lesser degree of patient-reported breast elevation and skin color change relative to baseline.

Clinical Experience Using Accelerated Partial Breast Irradiation: First 101 Patients Treated at Gamma West Cancer Services

We report our experience and outcomes with accelerated partial breast brachytherapy (APBI) for early stage breast cancer, both invasive and non-invasive breast cancers. The cancer was treated with breast-conserving therapy consisting of a lumpectomy followed by accelerated partial breast irradiation.

Efficacy of single-stage breast-conserving treatment using multicatheter partial breast brachytherapy evaluated by GEC-ESTRO phase 3 trial.

PurposeThe GEC-ESTRO has reported the equivalent outcomes of partial breast irradiation (PBI) using multicatheter interstitial brachytherapy (MCB) to whole breast irradiation (WBI) in breast-conserving therapy (BCT). We performed single-stage BCT with partial breast brachytherapy by intraoperative catheter placement. After the categorization of patients into inclusion and exclusion criteria on this trial, our databases were evaluated in order to translate it to Japanese patients.Material and methodsPatients undergoing BCT were retrospectively examined between November 2007 and December 2015. The technique is an open-cavity implant with a dose of 32 Gy in 8 fractions. The 4-year clinical outcomes of MCB-PBI were evaluated in the 2 distinct categories, and the comparison of the outcomes of MCB-PBI with WBI was performed in patients with unfavorable features.ResultsOf a total of 501 lesions undergoing BCT, 301 lesions were treated with MCB-PBI and 200 lesions with WBI. At the median follow-up time of 52 months, the 4-year rate of ipsilateral breast tumor recurrence (IBTR)-free, disease-free (DFS), and overall survival (OS) in patients with MCB-PBI and WBI were 98.9% vs. 98.0% (p = 0.56), 97.0% vs. 95.3% (p = 0.78), and 99.6% vs. 98.2% (p = 0.38), respectively. Although in exclusion cohort treated with MCB-PBI, IBTR-free, and disease-free survival were significantly worse than in inclusion cohort, non-significantly worse outcomes was demonstrated than in exclusion cohort with WBI; IBTR-free survival (95.0% vs. 97.2%, p = 0.24), and disease-free survival (95.0% vs. 95.8%, p = 0.31).ConclusionsSingle-stage BCT using MCB-PBI offered similar tumor control rates compering to WBI. However, further research is needed to define the benefit for patients with an exclusion criteria.

SU‐F‐T‐01: Optimization of the Accelerated Partial Breast Brachytherapy Fractionation with Consideration of Physical Doses to Tumor and Organ at Risk

Purpose:The accelerated partial breast irradiation (APBI) with brachytherapy prescribes 34Gy to be delivered in 10 fractions over 5 consecutive working days without considering the physical dose to the target and organs at risk (OARs) for an individual patient. The purpose of this study is to optimize the fractionation scheme by evaluating the radiation effect on tumor and OARs with a modified linear‐quadratic (LQ) model based on dose‐volume histograms (DVHs).Methods:Five breast patients treated with multilumen balloon brachytherapy were selected. The minimum skin and rib spacing were ranged from 2.5mm to 14.3mm and from 1.0mm to 25.0mm, respectively. The LQ model parameters were set as: (1) breast: α=0.08, β=0.028, doubling time Tpot=14.4 days, and starting time Tk=21days; (2) skin: acute reaction α=0.101, β=0.009; late reaction α=0.064, β=0.029; (3) rib: α=0.3, β=0.12. Boundary dose Dt was 6 Gy for both target and OARs. The relation between radiation effects on the tumor (ET) and OARs (EOAR) were plotted for fraction number from 1 to 20.Results:The value of radiation effect from routine 3.4Gyx10 fractions was used as reference, ETref and EOARref. If set ET=ETref, the fractionation that results in minimum EOAR values correspond to the optimal fractionation. For these patients, the optimal numbers are 10 fractions for skin acute reaction, 18 fractions for skin and rib late reaction while the doses per fraction are 3.4Gy and 2.05–2.10Gy, respectively. If set EOAR=EOARref, the fractionation that results in a maximum ET value corresponds to the optimal fractionation. The optimal fractionation is 3.4Gyx10 fractions for skin acute reaction, and 2.10–2.25Gyx18 fractions for skin late reaction and rib.Conclusion:For APBI brachytherapy, the routine 3.4Gyx10 fractions is optimal fractionation for skin acute reaction, while 2.05–2.25Gyx18 fractions is optimal fractionation for late reaction of skin and rib.

New Objective Method in Reporting the Breast Cosmetic Results Changes Following Breast Conserving Surgery and Adjuvant Intensity Modulated Multichannel Partial Breast Brachytherapy: The Objective Breast Cosmesis Scale (OBCS)

New Objective Method in Reporting the Breast Cosmetic Results Changes Following Breast Conserving Surgery and Adjuvant Intensity Modulated Multichannel Partial Breast Brachytherapy: The Objective Breast Cosmesis Scale (OBCS)

Feasibility of Using Day-of-Implant CT for Treatment Planning of Strut-Based Accelerated Partial-Breast Brachytherapy without the Necessity for Adaptive Replanning

Feasibility of Using Day-of-Implant CT for Treatment Planning of Strut-Based Accelerated Partial-Breast Brachytherapy without the Necessity for Adaptive Replanning