The American Brachytherapy Society consensus statement for accelerated partial-breast irradiation

PurposeAdjuvant radiation after breast-conserving surgery remains the standard-of-care treatment for patients with ductal carcinoma in situ and early-stage invasive breast cancer. Multiple alternatives to standard whole-breast irradiation exist including accelerated partial-breast irradiation (APBI). Therefore, the purpose of this APBI guideline is to provide updated data for clinicians as well as recommendations regarding appropriate patient selection and techniques to deliver APBI.MethodsMembers of the American Brachytherapy Society with expertise in breast cancer and breast brachytherapy in particular created an updated guideline for appropriate patient selection based on an extensive literature search and clinical experience. In addition, data were evaluated with respect to APBI techniques and recommendations presented.ResultsAppropriate candidates for APBI include patients aged 45 years or older, all invasive histologies and ductal carcinoma in situ, tumors 3 cm or less, node negative, estrogen receptor positive/negative, no lymphovascular space invasion, and negative margins. With respect to techniques, the strongest evidence is for interstitial brachytherapy and intensity-modulated radiation therapy APBI with moderate evidence to support applicator brachytherapy or three-dimensional conformal radiotherapy APBI. Intraoperative radiation therapy and electronic brachytherapy should not be offered regardless of technique outside of clinical trial.ConclusionsThe updated guidelines presented offer clinicians with a summary of data supporting APBI and guidelines for the appropriate and safe utilization of the technique.     

Radiation recall reaction with docetaxel administration after accelerated partial breast irradiation with electronic brachytherapy

PurposeAccelerated partial breast irradiation (APBI) offers several advantages over whole breast irradiation. Electronic brachytherapy may further reduce barriers to breast conserving therapy by making APBI more available. However, its toxicity profile is not well characterized.Methods and MaterialsA 60-year-old woman was treated with APBI using Axxent (Xoft, Sunnyvale, CA) electronic brachytherapy. One month after APBI, a cycle of docetaxel and cyclophosphamide was given. Within 3 weeks, the patient developed an ulcerative radiation recall reaction in the skin overlying the lumpectomy cavity. To investigate this toxicity, the skin dose from electronic brachytherapy was compared with the dose that would have been delivered by an iridium-192 (¹⁹²Ir) source. Additionally, a dose equivalent was estimated by adjusting for the increased relative biologic effectiveness (RBE) of low energy photons generated by the electronic source.ResultsUsing electronic brachytherapy, the skin dose was 537 cGy per fraction compared with 470 cGy for an ¹⁹²Ir source. Given an RBE for a 40 kV source of 1.28 compared with ¹⁹²Ir, the equivalent dose at the skin for an electronic source was 687 cGy-equivalents, a 46% increase.ConclusionsWe present a case of an ulcerative radiation recall reaction in a patient receiving APBI with electronic brachytherapy followed by chemotherapy. Our analysis shows that the use of electronic brachytherapy resulted in the deposition of significantly higher equivalent dose at the skin compared with ¹⁹²Ir. These findings suggest that standard guidelines (e.g., surface-to-skin distance) that apply to ¹⁹²Ir-based balloon brachytherapy may not be applicable to electronic brachytherapy.     

Preliminary results with accelerated partial breast irradiation in high-risk breast cancer patients

PurposeTo analyze prognostic factors in adequately staged breast cancer patients who were treated with accelerated partial breast irradiation (APBI).Methods and MaterialsAxillary staging was required for invasive carcinomas. Between February 2003 and June 2009, 204 women with early stage breast carcinomas were treated with APBI using multicatheter, MammoSite, or Contura brachytherapy to 34 Gy in 10 fractions 2 times per day. Six patient characteristics were examined for prognostic significance: (1) N stage, (2) estrogen receptor (ER) status, (3) histologic subtype, (4) margin status, (5) age, and (6) tumor size. The median followup was 22 months.ResultsThere were three failures in the ipsilateral breast (all were elsewhere failures), one relapse in the axilla, and seven relapses at any site. The presence of positive axillary node(s) had a significant adverse effect on ipsilateral breast tumor control (p = 0.045) and locoregional control (p = 0.001). The presence of an ER (?) tumor had a significant adverse effect on relapse-free survival (p = 0.04).ConclusionsThe patients with positive axillary node(s) were at increased risk for failure elsewhere in the ipsilateral breast or axilla, and the patients with ER (?) tumors were at increased risk for relapse at any site. However, it is unclear whether the pN1 and ER (?) patients would have faired any better if they had received whole breast irradiation rather than APBI. We believe that the patients with positive axillary node(s) or ER (?) tumors should be treated on clinical trials to better define the role of APBI.     

Three-year clinical outcome using the Contura multilumen balloon breast brachytherapy catheter to deliver accelerated partial breast irradiation (APBI): improving radiation standards for the optimal application of APBI

PurposeWe reviewed our institution’s 3-year clinical experience in treating patients with the Contura multilumen balloon (SenoRx, Inc., Aliso Viejo, CA) breast brachytherapy catheter to deliver accelerated partial breast irradiation (APBI).Methods and MaterialsForty-six patients treated with breast-conserving therapy received adjuvant radiation using the Contura catheter (34 Gy in 3.4 Gy fractions). Fourteen patients had Stage 0, 24 had Stage I, and 8 had Stage II breast cancer. Median follow-up was 36 months (range, 1–44 months).ResultsOnly one local recurrence developed (2%). The rate of persistent seroma formation at latest reported follow-up was 4.3% (2 patients) and the incidence of any clinically detectable telengiectasias was 2.2%. No major toxicities (0% Grade III) have occurred. The median skin dose (% of the prescribed dose) was 99.7. The median dose to 95% of the planning target volume for evaluation was 98.8%. The percentage of patients with excellent/good cosmetic results at 24 (n = 23) and 36 (n = 22) months was 100% and 97%, respectively.ConclusionAdjuvant APBI using the Contura multilumen balloon catheter exhibited similar locoregional control, cosmesis, and toxicities to other forms of APBI with similar lengths of follow-up. In addition, improved radiation standards for the delivery of APBI were demonstrated.     

RTOG 95-17, a Phase II trial to evaluate brachytherapy as the sole method of radiation therapy for Stage I and II breast carcinoma—year-5 toxicity and cosmesis

PurposeRadiation Therapy Oncology Group (RTOG) 95-17, a Phase II trial to evaluate multicatheter brachytherapy (mCathBrachy) as the sole method of radiation therapy for Stage I–II breast cancer (BrCa), was the first cooperative group trial in North America to evaluate accelerated partial breast irradiation (APBI) and include patient-reported outcomes (PROs). This report presents the year-5 toxicity and cosmesis data.Methods and MaterialsAfter lumpectomy and axillary dissection for invasive BrCa (tumor size <3 cm with zero to three positive lymph nodes), 100 patients (pts), 98 evaluable, were treated (txed) with mCathBrachy from 1997 to 2000 with 34 Gy administered twice daily in 10 high-dose-rate fractions or 45 Gy in 3.5–6 days as a low-dose-rate implant to 1–2 cm beyond the lumpectomy bed. The PROs and physician-reported outcomes of toxicity, cosmesis, and tx satisfaction at year-5 are reported here, defined as data submitted 54–78 months after tx.ResultsGrade (G) 1–2 skin toxicity developed in 78% of the pts and G3 in 13% (no G4). The tx effects included skin dimpling/indentation (37%), fibrosis (45%), telangiectasias (45%), skin catheter marks (54%), and symptomatic fat necrosis (15%). Breast asymmetry was reported in 73%. Rates of excellent-to-good cosmesis were similar between PROs (66%) and radiation oncologists (68%). The PROs of tx satisfaction at year-5 was 75%.ConclusionsRTOG 95-17 documents the year-5 skin toxicity and tx effects of mCathBrachy APBI, which are associated with PROs of good-to-excellent cosmesis and high tx satisfaction. This emphasizes the importance of PROs when assessing BrCa tx. National Surgical Adjuvant Breast and Bowel Project B39/RTOG 0413 will allow for definitive comparisons between APBI and whole breast radiation therapy.     

Early breast cancer treated with conservative surgery, adjuvant chemotherapy, and delayed accelerated partial breast irradiation with high-dose-rate brachytherapy

PurposeTo evaluate the feasibility and intermediate-term results of conservative surgery, adjuvant chemotherapy, and delayed accelerated partial breast irradiation (APBI) with high-dose-rate brachytherapy.Methods and MaterialsBetween 2000 and 2007, a total of 26 patients with a median age of 54 years were treated with conservative surgery followed by adjuvant chemotherapy and exclusive high-dose-rate brachytherapy. Inclusion criteria followed the Radiation Therapy Oncology Group 95-17 trial guidelines. The tumor bed was marked at the time of surgery (n = 2) or before brachytherapy (n = 24). The brachytherapy procedure was performed at a median of 22 weeks after surgery. A median of 14 brachytherapy catheters were placed in three to four parallel planes. A dose of 34.0 Gy in 10 b.i.d. fractions given over 5 consecutive days was prescribed to the clinical target volume (CTV₉₀).ResultsAfter a median followup of 53 months (range, 6.8–81), Radiation Therapy Oncology Group Grade 1–2 events and Grade 3 events were observed in 10 (38.4%) patients and 3 (11.5%) patients, respectively. No Grade 4–5 events were observed. Patients rated their cosmetic result as excellent (37.5%), good (50.0%), fair (8%), or poor (4%) based on the Wazer's Criteria. The 6-year actuarial local, elsewhere in the breast, and distant control rates were 100%, 96.2%, and 96.2%, respectively. Six-year disease-free survival and overall survival were 92.3% and 96.2%, respectively.ConclusionsPatients undergoing surgery and adjuvant chemotherapy can still be candidates for APBI. Optimal visualization of the internal lumpectomy scar before implantation is mandatory. Cosmetic results may be slightly worse due to the interaction between chemotherapy and APBI, and technical refinements may be needed in this group of patients.     

Comparison of survival and regional failure between accelerated partial breast irradiation and whole breast irradiation

PurposeTo compare rates of regional recurrence (RR) and overall survival (OS) between a pooled set of 1400 patients treated on the American Society of Breast Surgeons MammoSite (Hologic, Inc., Bedford, MA) Registry Trial to a cohort of 3600 patients treated with whole breast irradiation (WBI).Methods and MaterialsA total of 1440 women underwent accelerated partial breast irradiation (APBI) between 2002 and 2004 as part of the American Society of Breast Surgeons Registry Trial and a total of 3593 patients who received WBI were evaluated from the Surveillance Epidemiology and End Results database with treatment received between 1980 and 2009. A matched-pair analysis was performed based on age, receipt of hormonal therapy, chemotherapy, nodal status, and tumor size (1051 patients per arm). Rates of RR and OS were then analyzed for each group.ResultsAfter the match, no differences in patient characteristics were noted when tumor size was evaluated as a continuous variable. Rates of RR and OS were similar between the WBI and APBI groups. A Cox regression model found no difference between WBI and APBI with regard to RR; however, OS was improved in the APBI cohort (hazard ratio 0.008, p < 0.0001).ConclusionsWith one of the largest patient populations to date comparing WBI and APBI, no difference in RR or OS was noted between WBI and APBI treatment. Until the publication of prospective Phase III trials, these data support the continued use of APBI on protocol and off protocol in appropriately selected patients.     

GERICO-03 phase II trial of accelerated and partial breast irradiation in elderly women: Feasibility,reproducibility, and impact on functional status

PurposeTo analyze the feasibility, reproducibility, and impact on functional status of postoperative accelerated and partial breast irradiation (APBI) using interstitial high-dose rate-brachytherapy in women older than 70 years.Methods and MaterialsFrom July 2004 to April 2008, 46 patients were screened for enrollment in a nationwide prospective Phase II trial. A total of 40 patients were eligible according to the inclusion criteria (aged >70 years, T1–2 <30 mm, and pN0). The total delivered dose was 34 Gy of 10 fractions for 5 days. Feasibility and reproducibility were evaluated using a Quality Index (QI) defined as (V₁₀₀% ? clinical target volume)/V₁₀₀%. Skin toxicity was reported using Common Terminology Criteria for Adverse Events version 3.0. ABPI impact on functional dependence was evaluated using the Activity of Daily Living and Instrumental Activity of Daily Living scales. Reproducibility and feasibility were assessed with the optimal two-stage design of Simon.ResultsMedian age was 74 years (70–87 years). All patients were treated according to the protocol. Median Quality Index calculated for the 40 eligible patients was 13.3% (1–70%). It was considered acceptable, partially acceptable, and nonacceptable in 10, 28, and 2 patients, respectively. Within 12 months after APBI, overall rates of toxicity were 59%, 28%, and 2% for Grade 1, 2, and 3 events, respectively. Twelve months after APBI, 35 patients (87%) achieved excellent/good cosmetic result. Compared with baseline values, Activity of Daily Living and Instrumental Activity of Daily Living scores remained unchanged 6 and 12 months after APBI.ConclusionsAPBI by means of high-dose rate-brachytherapy is a feasible/reproducible technique without significant impact on functional dependence in the treatment of elderly women with early breast cancer.     

A comparison of long-term clinical outcomes of accelerated partial breast irradiation using interstitial brachytherapy as per GEC-ESTRO,ASTRO, updated ASTRO,and ABS guidelines

PurposeThe purpose of this study is to evaluate long-term clinical outcomes of women treated with accelerated partial breast irradiation (APBI) using multicatheter interstitial brachytherapy (MIB-APBI) with risk groups defined by Groupe Européen de Curie-thérapie and the European Society for Radiotherapy & Oncology (GEC-ESTRO), American Society for Radiation Oncology (ASTRO), updated ASTRO, and American Brachytherapy Society (ABS) guidelines and to elucidate the most appropriate guideline that could differentiate outcomes among its risk groups.Methods and MaterialsTwo hundred forty women underwent MIB-APBI during July 2000 to March 2013. Comparisons of long-term clinical outcomes (local control [LC], disease-free survival [DFS], cause-specific survival [CSS], and overall survival [OAS]) stratified by the risk groups proposed by the aforementioned patient selection guidelines were carried out on a prospectively maintained database.ResultsAt a median follow-up of 114 months, 10-year LC, DFS, and OAS were 90%, 81%, and 83.5%, respectively, for the entire group. There was no statistically significant difference in the LC rates for risk groups by ESTRO, ASTRO, updated ASTRO and ABS guidelines. The 10-year DFS and OAS for GEC-ESTRO low-, intermediate-, and high-risk group was 75%, 88%, and 60% (p = 0.02) and 86%, 93%, and 62% (p = 0.001), respectively. Ten-year DFS and OAS in the ABS 2018–acceptable and ABS 2018–unacceptable group were 78% and 67% (p = 0.01) and 88% and 69% (p = 0.001), respectively. No significant difference in any of the outcomes was observed with risk groups suggested by ASTRO or updated ASTRO consensus guidelines.ConclusionsNone of the current patient selection guidelines for APBI could differentiate LC (main APBI endpoint) among its risk groups, whereas GEC-ESTRO and ABS guideline could differentiate DFS and OAS.     

Use of serial CT imaging for the quality assurance of MammoSite therapy

PurposeAs experience with the MammoSite device for accelerated partial breast irradiation (APBI) has increased, more centers are starting to use three-dimensional (3D) treatment planning to generate plans with multiple nonequally weighted dwell positions. This report presents the use of serial computed tomography (CT) imaging, in addition to planar or ultrasound imaging, for the quality assurance of an APBI treatment using the elliptical MammoSite.Methods and MaterialsCT images of a patient implanted with a 4 cm × 6 cm elliptical MammoSite balloon were acquired. A treatment plan using multiple, nonequally weighted dwells was generated and delivered on Day 1 of a 10-fraction, twice-daily treatment. Before morning treatments on Days 2–5, the patient was reimaged on CT. Treatment plans on repeat CTs were generated two ways: using the decay-corrected plan from Day 1 (unadapted) vs. modifying the plan to account for changes in implant geometry (adapted). Adapted and unadapted plans on repeat CTs were compared with one another, and to the Day 1 plan.ResultsThe use of unadapted plans led to increased doses to normal tissues, particularly the skin. Adaptive planning on the repeat CTs was effective for maintaining acceptable dosimetry throughout treatment.ConclusionsSerial CT imaging was shown to provide a useful tool for the quality assurance of an elliptical balloon implant during the course of treatment. Serial CT imaging, as opposed to planar or ultrasound imaging, was necessary to evaluate skin dose and to facilitate adaptation of the treatment plan to satisfy limits for skin dose.     

Brachytherapy-based partial breast irradiation is associated with low rates of complications and excellent cosmesis

BackgroundRecent retrospective, claims-based analyses have suggested a potential increased rate of toxicities associated with brachytherapy-based accelerated partial breast irradiation (APBI). The purpose of this analysis was to examine cosmesis and toxicity data from the prospective American Society of Breast Surgeons (ASBS) breast brachytherapy registry trial to compare to the findings from the claims analyses.MethodsThe ASBS breast brachytherapy registry is a prospective nonblinded multi-institutional registry trial. Patients with Stage 0–II breast cancer undergoing breast conserving therapy were eligible. A total of 1665 patients were enrolled and 1449 treated between 2002 and 2004 with a median followup of 63 months. All patients were treated with the MammoSite (Hologic, Inc.) single-lumen device to deliver adjuvant APBI (34 Gy in 3.4 Gy fractions).ResultsThe rate of excellent/good cosmesis was 90.6% at 84 months. The rate of a complication (symptomatic seroma, infection, fat necrosis, telangiectasias) at 1 year/any time point was 24.2%/38.5%, whereas the rate of noninfectious complications at 1 year/any time point was 14.8%/28.9%. The rate of symptomatic seroma, fat necrosis, infection, and telangiectasia at any time was 13.4%, 2.5%, 9.6%, and 13.0%, respectively.ConclusionsThe final toxicity analysis from ASBS breast brachytherapy registry trial confirms the previously noted excellent cosmesis and toxicity profiles and fails to confirm retrospective claims analyses that have suggested higher rates of toxicity for brachytherapy-based APBI.     

Late chest wall toxicity after MammoSite breast brachytherapy

PurposeAccelerated partial breast irradiation (APBI) with the MammoSite^® breast brachytherapy (MBB) system is being investigated as an alternative to whole breast radiation in breast conservation therapy (BCT) at multiple centers worldwide. The newness of MBB means a complete understanding of long-term toxicity, particularly involving the chest wall, has yet to be completely articulated. We report the first pathologic rib fractures associated with MBB and dosimetric analysis of the original treatment plans.Methods and MaterialsAs part of ongoing quality assurance, we reviewed the records of 129 sequential patients who underwent MBB for breast cancer and identified those who subsequently had clinically significant and radiographically documented rib fracture(s) involving the ipsilateral chest wall. Equivalent tolerance doses yielding a 5% and 50% risk of rib toxicity within 5 years from treatment with 10 fractions (as with MBB) were previously calculated using the linear quadratic equation based on 2 Gy per fraction treatments delivered to one-third of the rib volume (TD5/5 = 37 Gy; TD50/5 = 44 Gy). The original radiation therapy plans were evaluated vis-à-vis the plane films or PET/CT images documenting the osseous abnormalities and presenting complaints to find the specific fractured ribs. The specific effected ribs were contoured on the planning CT in “bone windows” using the Nucletron MicroSelectron-classic V2 (Nucletron B.V., Veenendaal, The Netherlands) for this analysis and the original patient treatments. With these datasets, we determined the dose–volume characteristics of the effected ribs including maximal dose encompassing the entire rib on one CT slice, V_20Gy, V_30Gy, V_37Gy, V_44Gy , D₅₀, D₂₅, and D₅ (the mean dose to 50%, 25%, and 5% of the rib).ResultsBetween May 2002 and August 2007, three of 105 patients with a minimum of 6-months follow-up who underwent adjuvant APBI by MBB were found to have a total of five treatment-related rib fractures. The average dose–volume characteristics from the original plans were as follows: D₅₀ = 22.1 Gy, D₂₅ = 32.2 Gy, D₅ = 41.6 Gy, max dose to 1 cc = 34.8, D_max (to 0.1 cc) = 45.6 Gy, V₂₀ Gy = 57.4%, V₃₀ Gy = 30.8%, V₃₇ Gy = 15.9%, V₄₄ Gy = 6.6%, and max dose through rib = 35.8 Gy. Two patients sustained two rib fractures and 1 patient had a single rib fracture. Four of five fractures occurred in postmenopausal patients and two of five fractures occurred in a patient with a history of osteoporosis and exposure to adjuvant chemotherapy.ConclusionsFractures occurred in ribs with V₃₇ Gy and V₄₄ Gy each well below 33%. As long-term toxicity data accrue from APBI series, the traditional models for estimating the biologic equivalent dose may benefit from refinements that specifically address the unique radiobiologic and physical properties intrinsic to high-dose-rate brachytherapy for breast conservation therapy.     

A review of the safety implications of magnetic resonance imaging at field strengths of 3 Tesla and above

RationaleDiagnostic imaging is being driven by technological developments particularly so in the field of Magnetic Resonance Imaging (MRI). Electromagnetic fields used to produce images are becoming much stronger and switched more rapidly and it is essential that safety advice remains appropriate and current. Using a systematic methodology, this review aims to identify the clinical safety implications in performing MRI at field strengths of 3 Tesla (T) and above and determine whether the current clinical safety guidelines are appropriate.MethodReferences were sourced from The Cochrane Library, Centre for Reviews and Dissemination Science Direct, PubMed and Google Scholar. Related websites searched included The British Institute of Radiology, Society of Radiographers, Royal College of Radiologists, The Institution of Engineering and Technology, IMRSER (Institute for Magnetic Resonance Safety, Education, and Research), MagNet (NHS PASA). References supplied in retrieved papers were also checked for potential relevance. The use of consistent search terminology and inclusion and exclusion criteria ensured quality and provided rigour to conclusions drawn.ConclusionAccording to the literature retrieved, the current body of knowledge has allowed safety guidelines to be established for patient safety and these are both appropriate and valid at field strengths of 3 T.     

Compliance with the 24-Hour movement guidelines for the early years: Cross-sectional and longitudinal associations with executive function and psychosocial health in preschool children

ObjectiveTo examine whether meeting the Australian 24-Hour Movement Guidelines was associated with cognitive and psychosocial health in preschoolers.DesignProspective observational study.MethodsCross-sectional (n = 247) and 12-month longitudinal (n = 185) data from the PATH-ABC study were examined. Physical activity was assessed by accelerometry. Parents reported children’s screen time and sleep. Children were categorised at baseline as meeting: i) none/one guideline, ii) two guidelines, or iii) 24-Hour Movement Guidelines. Associations with executive functions and psychosocial health were examined using linear regression, adjusting for covariates and preschool clustering. Longitudinal associations were additionally adjusted for baseline levels of development.ResultsHigh proportions of children met the physical activity (94.3%) and sleep (89.9%) guidelines, 17.8% and 17.4% met screen time and 24-Hour Movement Guidelines, respectively. Cross-sectionally, children meeting both sleep and physical activity guidelines displayed better phonological working memory (p = 0.026) and shifting (p =  0.034) scores compared to children who did not. Meeting two (p = 0.037) and three (p = 0.017) guidelines were associated with better phonological working memory and shifting scores, respectively (vs. meeting 0/1 guideline). Longitudinally, children meeting the physical activity guideline at baseline displayed better shifting performance 12-months later compared to those who did not (p < 0.002). No associations with remaining cognitive outcomes, and no associations with psychosocial outcomes were evident.ConclusionsNull associations suggest that meeting the recommendations may not be adequate for broad cognitive and psychosocial health outcomes in preschoolers. However, supporting preschool children to meet the physical activity and sleep guidelines, may be beneficial for aspects of cognitive health.     

Four-year results using balloon-based brachytherapy to deliver accelerated partial breast irradiation with a 2-day dose fractionation schedule

PurposeWe present 4-year results from a Phase I/II trial using balloon-based brachytherapy to deliver accelerated partial breast irradiation in 2 days.Materials/MethodsForty-five patients received breast-conserving surgery followed by adjuvant radiation therapy using a balloon-based brachytherapy applicator delivering 2800 cGy in four fractions over 2 days. Outcomes analyzed include toxicities scored using the NCI Common Toxicity Criteria v3.0 scale, ipsilateral breast tumor recurrence, regional nodal failure, distant metastasis, disease-free survival, cause-specific survival, and overall survival.ResultsMedian age was 66 years (range, 48–83 years) and median tumor size was 0.6 cm (range, 0.2–2.3 cm). Five percent of patients were node positive (n = 2), whereas 73% was estrogen receptor positive (n = 33). Median followup was 3.7 years (2.4–7.0 years) with greater than 2 years of followup for all patients. Only Grades 1 and 2 chronic toxicities were noted with fat necrosis (18%) and asymptomatic seromas (42%) being the most common toxicities. Seven percent of patients developed ipsilateral rib fractures (n = 3), although this was not statistically associated with maximum rib dose (p = 0.31). Ninety-eight percent of patients had a good or excellent radiation-related cosmetic outcome at the time of last followup. There were no ipsilateral breast tumor recurrences or regional nodal failures; however, 2 patients developed distant metastases. Four-year actuarial disease-free survival, cause-specific survival, and overall survival were 96%, 100%, and 93%, respectively.ConclusionsTreatment of early-stage breast cancer patients with breast-conserving therapy using a 2-day radiation dose schedule resulted in acceptable chronic toxicity and similar clinical outcomes as standard 5-day fractionation.     

Impact of margin status on outcomes following accelerated partial breast irradiation using single-lumen balloon-based brachytherapy

PurposeTo examine the impact of margin status on clinical outcomes for patients enrolled in the American Society of Breast Surgeons (ASBrS) MammoSite^® Registry Trial.Methods and MaterialsOne thousand four hundred forty-nine cases of early-stage breast cancer underwent breast-conserving therapy with a single-lumen balloon-based applicator used to deliver adjuvant accelerated partial breast irradiation (34 Gy in 10, bid fractions). One thousand two hundred fifty-five cases (87%) had invasive breast cancer (median size = 10 mm) and 194 cases (13%) had ductal carcinoma in situ (DCIS; median size = 8 mm).ResultsPatients were stratified by margin status into negative (n = 1326), close (<2mm; n = 110), and positive (n = 13) margins. One hundred twenty-three cases (8.5%) had close or positive margins. Overall, no statistical difference in the 6-year rate of ipsilateral breast tumor recurrence (IBTR) was noted for close margins compared with that of margin-negative patients (8.7% vs. 4.1%, p = 0.10) or for positive margins compared with that of margin-negative patients (14.3% vs. 4.1%, p = 0.41). In patients with DCIS, there was a statistically significant increase in IBTR with close margins (17.6% vs. 4.2%, p = 0.004) and when close and positive margins were pooled (15.7% vs. 4.2%, p = 0.01 with a nonsignificant reduction in disease-free survival for DCIS patients with close margins (82.4% vs. 90.8%, p = 0.12). The increase in IBTR for close and close/positive patients was secondary to statistically significant increases in elsewhere failures rather than true recurrences/marginal misses.ConclusionNonsignificant increases in the rates of IBTR were noted with close and positive margins for invasive cancer with further data required to validate these findings.     

Multicatheter hybrid breast brachytherapy: a potential alternative for patients with inadequate skin distance

PurposeThe purpose of this study was to determine whether the ClearPath (CP) multicatheter hybrid device was able to achieve acceptable dosimetry in patients in whom the proximity of the breast surgical cavity to the skin precluded treatment with intracavitary MammoSite (MS) brachytherapy.Methods and materialsThe study consisted of 11 patients who had the MS catheter placed and who were subsequently not treated due to inadequate skin distance. A phantom scan of the CP multicatheter hybrid device was superimposed on the MS CT scan and a dosimetric comparison was performed.ResultsThe median MS balloon size, diameter, and minimum skin distance were 40 cc, 4.1 cm, and 5 mm, respectively. The D₉₀, V₁₀₀, V₁₅₀, and V₂₀₀ with MS vs. CP were 95.29% vs. 97.06%, 88.8% vs. 91.3%, 35.7% vs. 38.0%, and 9.4% vs. 9.6%, respectively. The median maximum skin dose was 5.5 Gy vs. 3.9 Gy (p <.0001). The median dose homogeneity index (DHI) was 0.60 vs. 0.59 (p = .09). The median maximum rib, heart, and lung dose were 2.17 Gy vs. 2.18 Gy, 2.17 Gy vs. 2.18 Gy, and 0.50 Gy vs. 0.56 Gy, respectively.ConclusionThe hybrid CP catheter reduced the skin dose significantly without compromising the planning target volume coverage, DHI, or dose to other critical organs. The use of this device has the potential to increase the applicability of accelerated partial breast brachytherapy (APBI) in patients with a surgical cavity close to skin compared with balloon brachytherapy.     

The use of the MammoSite balloon applicator in re-irradiation of the breast

PurposeTo examine the feasibility of using the MammoSite brachytherapy applicator in the retreatment of the previously irradiated breast.Methods and materialsBetween March 2004 and March 2007, three patients previously treated with external beam radiotherapy were retreated using the MammoSite brachytherapy device. Two patients were treated for an ipsilateral breast tumor recurrence after breast conservation surgery and postoperative irradiation, whereas the third patient developed an in-field breast cancer likely associated with Hodgkin's disease mantle irradiation 27 years before. The recurrent histology of two was ductal carcinoma in situ ([DCIS] one originally presenting as infiltrating ductal carcinoma [IDC] and the other as DCIS), whereas the Hodgkin's disease patient presented with IDC. All patients received a twice-daily tumor dose of 3400 cGy at 340 cGy/fraction. The mean maximum skin dose was 53.4% (range, 49.5–60.3%) of the prescribed dose.ResultsWith a mean followup of 32 months, no patient developed a local recurrence. Cosmesis in all three cases as graded by the National Surgical Adjuvant Breast and Bowel Project, cosmesis criteria was excellent (Grade I) in all cases. Dosimetric calculations demonstrated that the device allows for appropriate local irradiation while sparing the previously irradiated skin of the involved breast as defined by the protocol standard.ConclusionsUse of the MammoSite device in the treatment of the previously irradiated breast is feasible and may provide adequate local control as well as acceptable cosmesis in carefully selected patients.     

A new paradigm for calculating skin dose

PurposeMost institutions model breast epidermis with a surface contour and record the maximum dose on the external surface of the patient. The objective of this study was to compare the external surface contour (ext) model of the skin with our current volumetric model for skin for radiation treatment planning in accelerated partial breast irradiation brachytherapy.Methods and MaterialsA literature search was conducted to identify studies measuring breast epidermal thickness. Clinical plans were performed with a 2-mm contraction of the external surface contour. This 2-mm contraction of the external surface contour was used to approximate breast epidermis thickness. Then, the external surface contour was expanded 5 mm outside the external contour of the patient for the second skin model. Maximum doses from the two models were recorded and compared.ResultsThe average breast epidermal thickness from five studies was 1.68 mm. Mean percent difference between skin and ext + 5 mm for balloon plans, strut plans, and all plans was 10.1%, 14.5%, and 12.5%, respectively. Differences in doses between the two skin models were statistically significant (p < 0.0001).ConclusionsThe volumetric skin model was validated because the average breast epidermal thickness was 1.68 mm. The surface model for skin may underestimate the dose delivered to the epidermis by as much as 23.8%. The external surface contour method does not accurately represent the dermatologic skin thickness of the breast as the skin is modeled as a surface rather than a volume. These discrepancies may skew correlations of dose to skin and toxicity determinations.