Analysis of Treatment Efficacy, Cosmesis, and Toxicity Using the MammoSite Breast Brachytherapy Catheter to Deliver Accelerated Partial-Breast Irradiation: The William Beaumont Hospital Experience

Personalized Radiation Therapy for Breast Cancer

Breast cancer is diagnosed in nearly 3 million people worldwide. Radiation therapy is an integral component of disease management for patients with breast cancer, and is used after breast-conserving surgery or a mastectomy to reduce the risk of a local recurrence. The following review describes the methods used to personalize radiation therapy by optimizing patient selection, using advanced treatment techniques to lessen the radiation dose to normal organs, and using hypofractionation in order to shorten the duration of radiation treatment.

A Single-Institution Retrospective Study of Three-Fraction HDR Accelerated Partial Breast Irradiation

PURPOSE

Accelerated partial breast irradiation (APBI) delivered with high-dose-rate brachytherapy is a standard of care treatment typically delivered over 10 fractions. The TRIUMPH-T multi-institutional study recently demonstrated promising results using a shorter three fraction regimen, however there are limited additional published series using this regimen. Here, we report our experience and outcomes for patients treated as per the TRIUMPH-T regimen.

METHODS AND MATERIALS

This study was a retrospective single-institution analysis of patients who underwent lumpectomy followed by APBI (22.5 Gy in 3 fractions delivered over 2-3 days) using a Strut Adjusted Volume Implant (SAVI) applicator between November 2016 and January 2021. Dose-volume metrics were obtained from the clinically treated plan. Chart review was performed to determine locoregional recurrence and toxicities according to CTCAE v5.0.

RESULTS

Between 2016 and 2021, 31 patients were treated per the TRIUMPH-T protocol. Median followup was 31 months from completion of brachytherapy. There were no acute/late Grade 3 or higher toxicities. Cumulative late Grade 1 and 2 toxicities were seen in 58.1% and 9.7% of patients, respectively. Of note, four patients experienced locoregional recurrence: three ipsilateral breast tumor recurrences and one nodal recurrence. All three ipsilateral breast tumor recurrences occurred in patients who would be classified as "cautionary" based on ASTRO consensus guidelines due to age ≤50, lobular histology, or high grade.

CONCLUSIONS

Three-fraction HDR brachytherapy APBI was well-tolerated with no grade 3 or higher toxicities and an acceptably small percentage of grade 2 toxicities. Given the small sample size, the number of recurrences suggests that attention to appropriate patient selection is necessary until more long-term followup data is available.

Risk Factors for Fat Necrosis After Stereotactic Partial Breast Irradiation for Early-Stage Breast Cancer in a Phase 1 Clinical Trial

PURPOSE

This study reports predictive dosimetric and physiologic factors for fat necrosis after stereotactic-partial breast irradiation (S-PBI).

METHODS AND MATERIALS

Seventy-five patients with ductal carcinoma-in situ or invasive nonlobular epithelial histologies stage 0, I, or II, with tumor size <3 cm were enrolled in a dose-escalation, phase I S-PBI trial between January 2011 and July 2015. Fat necrosis was evaluated clinically at each follow-up. Treatment data were extracted from the Multiplan Treatment Planning System (Cyberknife, Accuray). Univariate and stepwise logistic regression analyses were conducted to identify factors associated with palpable fat necrosis.

RESULTS

With a median follow-up of 61 months (range: 4.3-99.5 months), 11 patients experienced palpable fat necrosis, 5 cases of which were painful. The median time to development of fat necrosis was 12.7 months (range, 3-42 months). On univariate analyses, higher V32.5-47.5 Gy (P < .05) and larger breast volume (P < .01) were predictive of any fat necrosis; higher V35-50 Gy (P < .05), receiving 2 treatments on consecutive days (P = .02), and higher Dmax (P = .01) were predictive of painful fat necrosis. On multivariate analyses, breast volume larger than 1063 cm³ remained a predictive factor for any fat necrosis; receiving 2 treatments on consecutive days and higher V45 Gy were predictive of painful fat necrosis. Breast laterality, planning target volume (PTV), race, body mass index, diabetic status, and tobacco or drug use were not significantly associated with fat necrosis on univariate analysis.

CONCLUSIONS

Early-stage breast cancer patients treated with breast conserving surgery and S-PBI in our study had a fat necrosis rate comparable to other accelerated partial breast irradiation modalities, but S-PBI is less invasive. To reduce risk of painful fat necrosis, we recommend not delivering fractions on consecutive days; limiting V42.5 < 50 cm³, V45 < 20 cm³, V47.5 < 1 cm³, Dmax ≤ 48 Gy and PTV < 100 cm³ when feasible; and counseling patients about the increased risk for fat necrosis when constraints are not met and for those with breast volume >1000 cm³.

Long term radiographic findings of breast brachytherapy: Implications of surgical volume

PURPOSE

Little is known about long-term radiographic findings after treatment with accelerated partial breast irradiation (APBI).

METHODS

Univariate and multivariate analysis of factors leading to formation and resolution of seroma were performed in patients treated with lumpectomy and APBI.

RESULTS

Post-treatment images of 129 patients were reviewed by one radiologist. Median surgical excision volume was 108.9 cc (range 20.5-681.9). Primary mode of imaging was mammogram. Median time from end of RT to first and last surveillance image was 6 and 54 months, respectively. Median number of images was 7 (range 3-12). Seroma was identified in 98 (76%) patients, with median maximum diameter of 3.9 cm. Forty (41%) patients experienced resolution of seroma, at a median time of 29 months (range 6-74). On univariate analysis, surgical excision volume was associated with seroma formation, and tumor stage and margin re-excision were significant on univariate and multivariate analysis. No factors were associated with seroma resolution.

CONCLUSION

Seroma formation after APBI resolves around 2.5 years for many patients, but persists for others possibly due to primary tumor and surgical excision volumes. With revised criteria on the definition of positive margins, smaller volumes may lead to decreased risk of seroma formation for future patients.

Breast conservation for male breast cancer: Case report of intraoperative radiation

Male breast cancer (MBC) comprises <1% of all breast cancers in the United States. MBC is typically treated with total mastectomy while the majority of female breast cancer is treated with breast conservation therapy combined with various forms of radiation. One method that has developed over the last two decades is the use of intraoperative radiation therapy (IORT) as a type of accelerated partial breast irradiation to direct the treatment field to the tumor bed. Since overall prognosis and systemic therapy recommendations for MBC are similar to breast cancer in women, we describe the first case of MBC treated with BCS and IORT. Our patient is a 62-year-old male who was found to have a right breast 1.6 cm palpable mass at the 10:00 position 1 cm radially from the nipple. Core biopsy demonstrated invasive ductal carcinoma, moderately differentiated, estrogen and progesterone receptor positive, and Her 2 Negative. The patient had a strong desire for breast conservation, and needed to minimize daily radiation treatments due to his work schedule. After discussion among our multidisciplinary tumor board, we felt this patient to be suitable for BCS and IORT given his age, favorable tumor subtype, size, and clinically early stage breast cancer. A right axillary sentinel lymph node biopsy and central lumpectomy was performed. The INTRABEAM device (Carl Zeiss Meditec, Oberkochen, Germany) was utilized for radiation delivery. The patient had negative margins on his final pathology. The postoperative course was uneventful and at the 6 month follow-up visit there were no issues and he had an excellent cosmetic outcome. BCS and IORT is an option in appropriately selected male patients with favorable subtype early stage breast cancer.

A Single-Site Retrospective, Nonrandomized Study of Accelerated Partial Breast Irradiation Brachytherapy for Early-Stage Breast Cancer Treatment to Evaluate Local Tumor Control, Cosmetic Outcome, and Toxicities

Purpose:

To evaluate the efficacy and safety of the accelerated partial breast irradiation brachytherapy with a combination of applicators at a community hospital cancer center.

Methods and Materials:

Between 2005 and 2009, 120 patients with early-stage breast cancer were being followed after treatment with accelerated partial breast irradiation brachytherapy using MammoSite, single or multilumen balloon, or Contura multilumen balloon. After their lumpectomy surgery, each patient was treated with Ir-192 high-dose rate unit following radiation therapy oncology group 0413 guidelines. The patients had multiple follow-ups at 6 months, 1 year, 2 years, 3 years, or more.

Results:

Based on the Harvard Breast Cosmesis Scale, 95.00% of patients described their cosmetic evaluation as the treated breast essentially the same as the opposite side (excellent) or minimal but identifiable effects were noticed from radiation (good). After a median follow-up of 36 months, the local recurrence rate was 1.66% and a disease-free survival is 98.3%. Forty-two patients reported 85 adverse events, which were fibrosis: 24.70%, hyperpigmentation: 20.00%, radiation skin reaction: 7.05%, seroma: 7.05%, breast pain: 7.05%, erythema: 5.88%, and other events were less than 5.00%. Of all the adverse events recorded, grade 1 to 3 events are 95.29% (n = 81), 2.35% (n = 2), and 2.35% (n = 2). There was no grade 4 or 5 events recorded.

Conclusions:

Our study has shown promising results for delivering radiation with MammoSite, single or multilumen balloon, or Contura multilumen balloon and has been successful in achieving local control in patients with early-stage breast cancer.

Contemporary Toxicity Profile of Breast Brachytherapy Versus External Beam Radiation After Lumpectomy for Breast Cancer

PURPOSE

We compared toxicities after brachytherapy versus external beam radiation therapy (EBRT) in contemporary breast cancer patients.

METHODS AND MATERIALS

Using MarketScan healthcare claims, we identified 64,112 women treated from 2003 to 2012 with lumpectomy followed by radiation (brachytherapy vs EBRT). Brachytherapy was further classified by multichannel versus single-channel applicator approach. We identified the risks and predictors of 1-year infectious and noninfectious postoperative adverse events using logistic regression and temporal trends using Cochran-Armitage tests. We estimated the 5-year Kaplan-Meier cumulative incidence of radiation-associated adverse events.

RESULTS

A total of 4522 (7.1%) patients received brachytherapy (50.2% multichannel vs 48.7% single-channel applicator). The overall risk of infectious adverse events was higher after brachytherapy than after EBRT (odds ratio [OR] = 1.21; 95% confidence interval [CI] 1.09-1.34, P<.001). However, over time, the frequency of infectious adverse events after brachytherapy decreased, from 17.3% in 2003 to 11.6% in 2012, and was stable after EBRT at 9.7%. Beyond 2007, there were no longer excess infections with brachytherapy (P=.97). The overall risk of noninfectious adverse events was higher after brachytherapy than after EBRT (OR=2.27; 95% CI 2.09-2.47, P<.0001). Over time, the frequency of noninfectious adverse events detected increased: after multichannel brachytherapy, from 9.1% in 2004 to 18.9% in 2012 (Ptrend = .64); single-channel brachytherapy, from 12.8% to 29.8% (Ptrend<.001); and EBRT, from 6.1% to 10.3% (Ptrend<.0001). The risk was significantly higher with single-channel than with multichannel brachytherapy (hazard ratio = 1.32; 95% CI 1.03-1.69, P=.03). Of noninfectious adverse events, 70.9% were seroma. Seroma significantly increased breast pain risk (P<.0001). Patients with underlying diabetes, cardiovascular disease, and treatment with chemotherapy had increased infectious and noninfectious adverse events. The 5-year incidences of fat necrosis, breast pain, and rib fracture were slightly higher after brachytherapy than after EBRT (13.7% vs 8.1%, 19.4% vs 16.0%, and 1.6% vs 1.3%, respectively), but the risks were not significantly different for multichannel versus single-channel applicators.

CONCLUSION

Toxicities after breast brachytherapy were distinct from those after EBRT. Temporal toxicity trends may reflect changing technology and evolving practitioner experience with brachytherapy.

Accelerated partial breast irradiation: a review and evaluation of indications for treatment

Accelerated partial breast irradiation (APBI) represents a well-studied treatment modality for the delivery of adjuvant radiation therapy following breast-conserving surgery. Interstitial APBI represents the APBI technique with the longest follow-up to date; data from randomized trials and matched pair analyses demonstrate equivalent local control to traditional whole-breast irradiation with comparable rates of toxicity and improved cosmesis. While less mature, prospective data support the efficacy and safety of applicator-based brachytherapy with new multilumen applicators offering the potential for improved outcomes. External beam APBI represents a noninvasive technique; however, concerns regarding toxicity with this technique have emerged though newer techniques may mitigate these concerns. Multiple guidelines have been published based on traditional clinical and pathologic criteria to help physicians offer APBI to appropriately selected patients.

Comparative dosimetric findings using accelerated partial breast irradiation across five catheter subtypes

Purpose

Accelerated partial breast irradiation (APBI) with balloon and strut adjusted volume implants (SAVI) show promising results with excellent tumor control and minimal toxicity. Knowing the factors that contribute to a high skin dose, rib dose, and D₉₅ coverage may reduce toxicity, improve tumor control, and help properly predict patient outcomes following APBI.

Methods and materials

A retrospective analysis of 594 patients treated with brachytherapy based APBI at a single institution from May 2008 to September 2014 was grouped by applicator subtype. Patients were treated to a total of 34 Gy (3.4 Gy x 10 fractions over 5 days delivered BID) targeting a planning target volume (PTV) 1.0 cm beyond the lumpectomy cavity using a high dose rate source.

Results

SAVI devices had the lowest statistically significant values of D_maxSkin (81.00 ± 29.83), highest values of D₉₀ (101.50 ± 3.66), and D₉₅ (96.09 ± 4.55). SAVI-mini devices had the lowest statistically significant values of D_maxRib (77.66 ± 32.92) and smallest V₁₅₀ (18.01 ± 3.39). Multi-lumen balloons were able to obtain the smallest V₂₀₀ (5.89 ± 2.21). Strut-based applicators were more likely to achieve a D_maxSkin and a D_maxRib less than or equal to 100 %. The effect of PTV on V₁₅₀ showed a strong positive relationship (p < .001). PTV and D_maxSkin showed a weak negative relationship in multi-lumen applicators (p = .016) and SAVI-mini devices (p < .001). PTV and D_maxRib showed a weak negative relationship in multi-lumen applicators (p = .009), SAVI devices (p < .001), and SAVI-mini devices (p < .001).

Conclusion

PTV volume is strongly correlated with V₁₅₀ in all devices and V₂₀₀ in strut based devices. Larger PTV volumes result in greater V₁₅₀ and V₂₀₀, which could help predict potential risks for hotspots and resulting toxicities in these devices. PTV volume is also weakly negatively correlated with max skin dose and max rib dose, meaning that as the PTV volumes increase one can expect slightly smaller max skin and rib doses. Strut based applicators are significantly more effective in keeping skin and rib dose constraints under 125 and 100 % when compared to any balloon based applicator.

Techniques for intraoperative radiation therapy for early-stage breast carcinoma

ABSTRACT 

Intraoperative radiation therapy (IORT) is a method of accelerated partial breast irradiation developed to replace other longer courses of radiotherapy with a single radiation session administered at the time of breast-conserving surgery. The purpose of this review is to summarize the advantages and disadvantages of breast IORT techniques that are currently available, as well to consider potential alternative techniques for breast IORT or ultra-short course breast radiotherapy. Furthermore, we highlight the published outcomes for the IORT treatment approaches including: electron therapy, superficial photon therapy and other techniques. Potential future directions of IORT are explored including novel IORT techniques utilizing intraoperative brachytherapy with in-room imaging and rapid treatment planning.

Timing of infectious complications following breast-conserving therapy with catheter-based accelerated partial breast irradiation

BACKGROUND

Accelerated partial breast irradiation (APBI) has been used as an alternative to whole-breast irradiation as part of breast-conserving therapy. Indications and outcomes are topics of ongoing investigation. Previous publications have focused on early postoperative infections and reported low rates of delayed infection. We investigated the pattern of infection after catheter-based APBI at our institution.

METHODS

Patients who underwent single-entry catheter-based APBI were identified from an institutional prospective registry including data regarding comorbidities and outcomes. Time of infection was calculated from the date of definitive catheter insertion and classified as early (≤30 days) or delayed.

RESULTS

A total of 91 breast cancer patients were treated with APBI and enrolled in the registry from 2009 to 2011. The median follow-up was 484 days. Breast infection occurred in 13 (14.3 %), with 3 (3.3 %) occurring within 30 days of catheter placement and 10 (11.0 %) in a delayed fashion. Four patients required hospital admission, five underwent percutaneous aspiration, and one underwent incision and drainage. Eight were treated as outpatients with oral antibiotics alone.

CONCLUSIONS

Consistent with other reports, we found an overall infection rate of 14.3 % with single-entry catheter-based APBI. There were substantially fewer infections in the early postoperative period than reported elsewhere, but there were more delayed infections. The intensive follow-up in our study likely identified late infections that may not have otherwise been recognized. Vigilance for infectious complications must continue beyond the immediate treatment period in patients undergoing catheter-based APBI. These infections can range in severity but typically can be managed in an outpatient setting.

Transforming growth factor β-1 (TGF-β1) is a serum biomarker of radiation induced fibrosis in patients treated with intracavitary accelerated partial breast irradiation: preliminary results of a prospective study

PURPOSE

To examine a relationship between serum transforming growth factor β -1 (TGF-β1) values and radiation-induced fibrosis (RIF).

METHODS AND MATERIALS

We conducted a prospective analysis of the development of RIF in 39 women with American Joint Committee on Cancer stage 0-I breast cancer treated with lumpectomy and accelerated partial breast irradiation via intracavitary brachytherapy (IBAPBI). An enzyme-linked immunoassay (Quantikine, R&D, Minneapolis, MN) was used to measure serum TGF-β1 before surgery, before IBAPBI, and during IBAPBI. Blood samples for TGF-β1 were also collected from 15 healthy, nontreated women (controls). The previously validated tissue compliance meter (TCM) was used to objectively assess RIF.

RESULTS

The median time to follow-up for 39 patients was 44 months (range, 5-59 months). RIF was graded by the TCM scale as 0, 1, 2, and 3 in 5 of 20 patients (25%), 6 of 20 patients (30%), 5 of 20 patients (25%), and 4 of 20 patients (20%), respectively. The mean serum TGF-β1 values were significantly higher in patients before surgery than in disease-free controls, as follows: all cancer patients (30,201 ± 5889 pg/mL, P=.02); patients with any type of RIF (32,273 ± 5016 pg/mL, P<.0001); and women with moderate to severe RIF (34,462 ± 4713 pg/mL, P<0.0001). Patients with moderate to severe RIF had significantly elevated TGF-β1 levels when compared with those with none to mild RIF before surgery (P=.0014) during IBAPBI (P≤0001), and the elevation persisted at 6 months (P≤.001), 12 months (P≤.001), 18 months (P≤.001), and 24 months (P=.12). A receiver operating characteristic (ROC) curve of TGF-β1 values predicting moderate to severe RIF was generated with an area under the curve (AUC)ROC of 0.867 (95% confidence interval 0.700-1.000). The TGF-β1 threshold cutoff was determined to be 31,000 pg/mL, with associated sensitivity and specificity of 77.8% and 90.0%, respectively.

CONCLUSIONS

TGF-β1 levels correlate with the development of moderate to severe RIF. The pre-IBAPBI mean TGF-β1 levels can serve as an early biomarker for the development of moderate to severe RIF after IBAPBI.

Comparison of planning techniques when air/fluid is present using the strut-adjusted volume implant (SAVI) for HDR-based accelerated partial breast irradiation

The presence of air/fluid surrounding implantable devices used for partial breast irradiation may significantly impact dose coverage to at-risk tissue. Of the 67 total patients retrospectively evaluated for this study, 32 (48%) had greater than 1 cc volume of air/fluid extending outside of the strut-adjusted volume implant (SAVI) device surface and were selected for comparison of planning approaches. The planning approaches utilized two different definitions of PTV_EVAL. One definition of a PTV_EVAL (PTV_EVALSAVI) was based on expanding 1 cm beyond the SAVI device only while accounting for the air/fluid using the NSABP Protocol B-39/RTOG Protocol 0413. The second PTV_EVAL definition (PTV_EVALCAV) was based on expanding 1 cm beyond the cavity (SAVI device plus air/fluid volume). The results indicate use of the B-39 formalism to account for air/fluid displacing the PTV_EVAL may overestimate the dose coverage to the at-risk tissue, especially for large contiguous volumes of air/fluid. Using the SAVI device to optimize dose covering the PTV_EVALCAV volume surrounding the cavity improves dosimetric coverage to at-risk tissue by 11.3% and 8.7% for V100 and V90, respectively, while the average V150 and V200 indices for PTV_EVALCAV increased by 9.1 cc and 5.0cc, respectively, and the average maximum rib and skin doses increased by 11.1% and 6.1%, respectively. The maximum skin dose, rib dose, V150, and V200 all met the planning objectives despite any increase in these parameters.

Four-year clinical update from a prospective trial of accelerated partial breast intensity-modulated radiotherapy (APBIMRT)

This prospective Phase II single-arm study gathered data on the use of intensity-modulated radiotherapy (IMRT) to deliver accelerated partial breast irradiation (APBI). Four-year efficacy, cosmesis, and toxicity results are presented. Between February 2004 and September 2007, 136 consecutive patients with Stage 0/I breast cancer and negative margins ≥0.2 cm were treated on protocol. Patients received 38.5 Gy in 10 equal fractions delivered twice daily. Breast pain and cosmesis were rated by patient, and cosmesis was additionally evaluated by physician per Radiation Therapy Oncology Group (RTOG) criteria. The National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE v3.0) was used to grade toxicities. 136 patients (140 breasts) with median follow-up of 53.1 months (range, 8.9-83.2) were evaluated. Population characteristics included median age of 61.9 years and Tis (13.6 %), T1a (18.6 %), T1b (36.4 %), and T1c (31.4 %). Kaplan-Meier estimates at 4 years: ipsilateral breast tumor recurrence 0.7 %; contralateral breast failure 0 %; distant failure 0.9 %; overall survival 96.8 %; and cancer-specific survival 100 %. At last follow-up, patients and physicians rated cosmesis as excellent/good in 88.2 and 90.5 %, respectively; patients rated breast pain as none/mild in 97.0 %. Other observations included edema (1.4 %), telangiectasia (3.6 %), five cases of grade 1 radiation recall (3.6 %), and two cases of rib fractures (1.4 %). This analysis represents the largest cohort and longest follow-up of APBI utilizing IMRT reported to date. Four-year results continue to demonstrate excellent local control, survival, cosmetic results, and toxicity profile.

Increased rates of long-term complications after MammoSite brachytherapy compared with whole breast radiation therapy

BACKGROUND

Due to its short duration of therapy and low rates of local recurrence, women undergoing breast conservation are increasingly opting for partial breast irradiation with the MammoSite (Cytyc/Hologic) catheter. In early follow-up studies, few complications were reported. Few data, however, exist regarding longer-term complications. We compared the long-term local toxicities of MammoSite partial breast irradiation with those resulting from whole breast radiation.

STUDY DESIGN

This was a retrospective study performed in a single academic medical center. All patients who underwent breast-conserving surgery between 2003 and 2008, who met institutional criteria for brachytherapy, were included. We compared women treated with MammoSite with patients treated with whole breast radiation therapy (WBRT). Endpoints included incidence of palpable masses at the lumpectomy site, telangiectasias, and local recurrence.

RESULTS

Seventy-one MammoSite patients and 245 WBRT patients were well matched with regard to clinical characteristics. Median follow-up was 4 years. A palpable mass developed at the site of lumpectomy in 27% of the MammoSite patients compared with 7% of the WBRT patients (p < 0.0001). Telangiectasias developed more frequently in the MammoSite group than in the WBRT group (24% vs 4%, p < 0.001). Forty-two percent of patients treated with MammoSite developed a palpable mass, telangectasia, or both.

CONCLUSIONS

Palpable masses and telangiectasias are frequent long-term complications after MammoSite brachytherapy and occur at a significantly higher rate after MammoSite brachytherapy than after WBRT. This increased rate of long-term local toxicity should be considered when counseling women on options for adjuvant radiation therapy after breast-conserving surgery.

The American Brachytherapy Society consensus statement for accelerated partial breast irradiation

PURPOSE

To develop clinical guidelines for the quality practice of accelerated partial breast irradiation (APBI) as part of breast-conserving therapy for women with early-stage breast cancer.

METHODS AND MATERIALS

Members of the American Brachytherapy Society with expertise in breast cancer and breast brachytherapy in particular devised updated guidelines for appropriate patient evaluation and selection based on an extensive literature search and clinical experience.

RESULTS

Increasing numbers of randomized and single and multi-institution series have been published documenting the efficacy of various APBI modalities. With more than 10-year followup, multiple series have documented excellent clinical outcomes with interstitial APBI. Patient selection for APBI should be based on a review of clinical and pathologic factors by the clinician with particular attention paid to age (≥50 years old), tumor size (≤3cm), histology (all invasive subtypes and ductal carcinoma in situ), surgical margins (negative), lymphovascular space invasion (not present), and nodal status (negative). Consistent dosimetric guidelines should be used to improve target coverage and limit potential for toxicity following treatment.

CONCLUSIONS

These guidelines have been created to provide clinicians with appropriate patient selection criteria to allow clinicians to use APBI in a manner that will optimize clinical outcomes and patient satisfaction. These guidelines will continue to be evaluated and revised as future publications further stratify optimal patient selection.

Evaluation of current consensus statement recommendations for accelerated partial breast irradiation: a pooled analysis of William Beaumont Hospital and American Society of Breast Surgeon MammoSite Registry Trial Data

PURPOSE

To determine whether the American Society for Radiation Oncology (ASTRO) Consensus Statement (CS) recommendations for accelerated partial breast irradiation (APBI) are associated with significantly different outcomes in a pooled analysis from William Beaumont Hospital (WBH) and the American Society of Breast Surgeons (ASBrS) MammoSite® Registry Trial.

METHODS AND MATERIALS

APBI was used to treat 2127 cases of early-stage breast cancer (WBH, n=678; ASBrS, n=1449). Three forms of APBI were used at WBH (interstitial, n=221; balloon-based, n=255; or 3-dimensional conformal radiation therapy, n=206), whereas all Registry Trial patients received balloon-based brachytherapy. Patients were divided according to the ASTRO CS into suitable (n=661, 36.5%), cautionary (n=850, 46.9%), and unsuitable (n=302, 16.7%) categories. Tumor characteristics and clinical outcomes were analyzed according to CS group.

RESULTS

The median age was 65 years (range, 32-94 years), and the median tumor size was 10.0 mm (range, 0-45 mm). The median follow-up time was 60.6 months. The WBH cohort had more node-positive disease (6.9% vs 2.6%, P<.01) and cautionary patients (49.5% vs 41.8%, P=.06). The 5-year actuarial ipsilateral breast tumor recurrence (IBTR), regional nodal failure (RNF), and distant metastasis (DM) for the whole cohort were 2.8%, 0.6%, 1.6%. The rate of IBTR was not statistically higher between suitable (2.5%), cautionary (3.3%), or unsuitable (4.6%) patients (P=.20). The nonsignificant increase in IBTR for the cautionary and unsuitable categories was due to increased elsewhere failures and new primaries (P=.04), not tumor bed recurrence (P=.93).

CONCLUSIONS

Excellent outcomes after breast-conserving surgery and APBI were seen in our pooled analysis. The current ASTRO CS guidelines did not adequately differentiate patients at an increased risk of IBTR or tumor bed failure in this large patient cohort.

Accelerated partial breast irradiation: the need for well-defined patient selection criteria, improved volume definitions, close follow-up and discussion of salvage treatment

Breast-conserving therapy, including whole breast irradiation, has become a well-established alternative to mastectomy in early-stage breast cancer patients, with similar survival rates and better cosmetic outcome. However, many women are still treated with mastectomy, due to logistical issues related to the long course of radiotherapy (RT). To reduce mastectomy rates and/or omission of RT after breast-conserving surgery, shorter, hypofractionated RT treatments have been introduced. More recently, the necessity of routinely treating the entire breast in all patients has been questioned, leading to the development of partial breast radiotherapy. With accelerated partial breast irradiation (APBI) these two approaches have been combined: the tumor bed with a 1-2 cm margin is irradiated either intra-operatively (single fraction) or postoperatively over 5-15 days. Different techniques have been developed, including interstitial brachytherapy, intra-cavity brachytherapy, intra-operative radiotherapy and external beam radiotherapy. These techniques are being evaluated in several ongoing phase III studies. Since its introduction, APBI has been the subject of continuous debate. ASTRO and GEC-ESTRO have published guidelines for patient selection for APBI, and strongly recommend that APBI be carried out within ongoing clinical trials. Recently, the patient selection criteria for APBI have also been up for debate, following the publication of results from different groups that do/do not confirm a difference in recurrence risk among the ASTRO defined risk groups. This paper reviews the different APBI techniques, current recommendations for patient selection, available clinical data and ongoing clinical trials. A case report is included to illustrate the need for careful follow-up of patients treated with APBI.

Patterns of use and short-term complications of breast brachytherapy in the national medicare population from 2008-2009

PURPOSE

Brachytherapy has disseminated into clinical practice as an alternative to whole-breast irradiation (WBI) for early-stage breast cancer; however, current national treatment patterns and associated complications remain unknown.

PATIENTS AND METHODS

We constructed a national sample of Medicare beneficiaries ages 66 to 94 years who underwent breast-conserving surgery from 2008 to 2009 and were treated with brachytherapy or WBI. We used hospital referral regions (HRRs) to assess national treatment variation and an instrumental variable analysis to compare complication rates between treatment groups, adjusting for patient and clinical characteristics. We compared overall, wound and skin, and deep-tissue and bone complications between brachytherapy and WBI at 1 year of follow-up.

RESULTS

Of 29,648 women in our sample, 4,671 (15.8%) received brachytherapy. The percent of patients receiving brachytherapy varied substantially across HRRs, ranging from 0% to over 70% (interquartile range, 7.5% to 23.3%). Of women treated with brachytherapy, 34.3% had a complication compared with 27.3% of women undergoing WBI (P < .001). After adjusting for patient and clinical characteristics, 35.2% of women treated with brachytherapy (95% CI, 28.6 to 41.9) had a complication compared with 18.4% treated with WBI (95% CI, 15.5 to 21.3; P value for difference, <.001). Brachytherapy was associated with a 16.9% higher rate of wound and skin complications compared with WBI (95% CI, 10.0 to 23.9; P < .001), but there was no difference in deep-tissue and bone complications.

CONCLUSION

Brachytherapy is commonly used among Medicare beneficiaries and varies substantially across regions. After 1 year, wound and skin complications were significantly higher among women receiving brachytherapy compared with those receiving WBI.

Brachytherapy in accelerated partial breast irradiation (APBI) - review of treatment methods

Breast conserving surgery (BCS) with following radiotherapy (EBRT) of the conserved breast became widely accepted in the last decades as the treatment of early invasive breast cancer. In an early stage of breast cancer, research has shown that the area requiring radiation treatment to prevent cancer from local recurrence is the breast tissue that surrounds the area where the initial cancer was removed. Accelerated partial breast irradiation (APBI) is an approach that treats only the lumpectomy bed with 1-2 cm margin, rather than the whole breast and as a result allows accelerated delivery of the radiation dose in four to five days. Published results of APBI are very promising. It is evident that APBI will play a role in the management of a selected group of early breast cancer. We discuss current status, indications, technical aspects and recently published results of APBI using different brachytherapy techniques.

Breast cancer recurrence after inadvertent malpositioning of a partial breast radiation catheter

Accelerated partial breast irradiation (APBI) is an alternative to receiving whole breast radiation in carefully selected patients. Because breast cancer local recurrence rates are low and follow-up has been short-term, the exact cause of recurrences after APBI has been difficult to evaluate. We report the first case of documented radiation balloon catheter malpositioning that resulted in local recurrence. Patients undergo CT imaging of the breast after radiation balloon catheter placement for radiotherapy treatment planning, which evaluates adequate conformance of the balloon to the surrounding breast parenchyma and confirms a >7 mm distance between the balloon surface and the skin surface. Although true local recurrences are rare in appropriately selected partial breast irradiation candidates, inadvertent malpositioning of the radiation treatment catheter can increase the risk. This case is presented to illustrate the importance of comparing CT radiation planning images, with treatment catheter in place, to the original diagnostic breast imaging studies to confirm proper catheter positioning (in addition to measuring balloon to skin distance and conformance) prior to initiating radiotherapy.

Ductal carcinoma in situ of the breast

Ductal carcinoma in situ (DCIS) of the breast represents a complex, heterogeneous pathologic condition in which malignant epithelial cells are confined within the ducts of the breast without evidence of invasion. The increased use of screening mammography has led to a significant shift in the diagnosis of DCIS, accounting for approximately 27% of all newly diagnosed cases of breast cancer in 2011, with an overall increase in incidence. As the incidence of DCIS increases, the treatment options continue to evolve. Consistent pathologic evaluation is crucial in optimizing treatment recommendations. Surgical treatment options include breast-conserving surgery (BCS) and mastectomy. Postoperative radiation therapy in combination with breast-conserving surgery is considered the standard of care with demonstrated decrease in local recurrence with the addition of radiation therapy. The role of endocrine therapy is currently being evaluated. The optimization of diagnostic imaging, treatment with regard to pathological risk assessment, and the role of partial breast irradiation continue to evolve.

Relationship between irradiated breast volume and late normal tissue complications: a systematic review

The concept of radiation dose-volume effect has been exploited in breast cancer as boost treatment for high risk patients and more recently in trials of Partial Breast Irradiation for low risk patients. However, there appears to be paucity of published data on the dose-volume effect of irradiation on breast tissue including the recently published report on Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC). This systematic review looks at the current literature for relationship between irradiated breast volume and normal tissue complications and introduces the concept of dose modulation.

Acute toxicity and early cosmetic outcome in patients treated with multilumen balloon brachytherapy with skin spacing ≤ 7.0 millimeters

Purpose

To review institutional experience treating patients who underwent breast conserving surgery and adjuvant accelerated partial breast irradiation with multilumen balloon brachytherapy (MLB) with close skin spacing (≤7 mm).

Material and methods

Since July 2009, 26 patients with skin spacing ≤ 7.0 mm were treated with breast-conserving therapy and adjuvant MLB brachytherapy. Patients were treated with either the Contura or MammoSite ML catheter to a total dose of 34 Gy in 10 fractions. Patients were assessed for acute toxicity at the completion of treatment and 1-month post treatment. Cosmesis and late toxicity were assessed at three-month intervals thereafter.

Results

The median age of the patients was 56 years and median follow-up was 9 months. Sixteen patients had skin spacing of 5.0–7.0 mm, 10 with < 5.0 mm (median 5.8). The median percentage of the target (PTV_EVAL) receiving ≥ 95% of the prescription dose was 95.6%. The median volume of PTV_EVAL receiving ≥ 200% of the prescription dose was 6.1 cc. The maximum skin dose was 118.2% (median). The most commonly observed acute toxicity was grade 1-2 dermatitis (65.4%). The rate of post-treatment seroma and infection was 38.5% and 3.8%, respectively. Excellent/good cosmetic outcomes seen at the time of last follow-up was 92.3%.

Conclusions

MLB brachytherapy is safe and feasible in patients with close skin spacing, with acute toxicity and early cosmesis similar to other published series. These devices may broaden the application of balloon brachytherapy in patients previously excluded from this treatment based on anatomy.

Accelerated partial breast irradiation in early breast cancer: focus on intraoperative treatment with electrons (ELIOT)

Wide tumor resection plus postoperative whole breast irradiation is standard treatment for early breast cancer. Irradiation decreases recurrence rates, but may cause poor cosmesis, breast pain, and cardiac and lung toxicity. Accelerated partial breast irradiation is increasingly used in the hope of increasing convenience, decreasing sequelae and maintaining cure rates. Intraoperative radiotherapy with electrons is an attractive accelerated partial breast irradiation technique because collimator placement is under the direct control of the surgeon who removes the tumor, the skin is spared, shielding protects the chest wall and complete irradiation can be given in a single intraoperative session (avoiding 5-7 weeks of whole breast irradiation). Intraoperative radiotherapy with electrons seems as safe as whole breast irradiation; however, long-term results on local control and survival are not available yet.

Six-year analysis of treatment-related toxicities in patients treated with accelerated partial breast irradiation on the American Society of Breast Surgeons MammoSite Breast Brachytherapy registry trial

BACKGROUND

The American Society of Breast Surgeons (ASBrS) enrolled women in a registry trial to prospectively study patients treated with the MammoSite RTS device. This report presents 6-year data on treatment-related toxicities from the trial.

METHODS

A total of 1449 primary early-stage breast cancers were treated with accelerated partial breast irradiation (APBI) using the MammoSite device (34 Gy in 10 fractions) in 1440 women. Of these, 1255 case (87%) had invasive breast cancer (IBC) (median size = 10 mm) and 194 cases (13%) had ductal carcinoma in situ (DCIS) (median size = 8 mm). Median follow-up was 59 months. Fisher exact test was performed to correlate categorical covariates with toxicity.

RESULTS

Breast seromas were reported in 28% of cases (35.5% with open cavity and 21.7% with closed cavity placement). Also, 13% of all treated breasts developed symptomatic seromas, and 77% of these seromas developed during the 1st year after treatment. There were 172 cases (11.9%) that required drainage to correct. Use of chemotherapy and balloon fill >50 cc were associated with the development of symptomatic seromas. Also, 2.3% of patients developed fat necrosis (FN). The incidence of FN during years 1 and 2 were 0.9% and 0.8%, respectively. Seroma formation, use of hormonal therapy, breast infection, and A/B cup size were associated with fat necrosis. There were 138 infections (9.5%) recorded; 98% occurred during the 1st year after treatment. Chemotherapy and seroma formation were associated with the development of infections.

CONCLUSIONS

Treatment-related toxicities 6 years after treatment with APBI using the MammoSite device are similar to those reported with other forms of APBI with similar follow-up.

Tumor bed-to-skin distance using accelerated partial-breast irradiation with the strut-adjusted volume implant device

PURPOSE

Because of the risk of skin toxicity with single dwell position, single-lumen brachytherapy devices are sometimes contraindicated for tumor cavities 5-7mm from the skin surface. We discuss the use of multicatheter device to treat patients with tumor bed-to-skin distances <7mm.

METHODS AND MATERIALS

We treated 117 patients with accelerated partial-breast irradiation brachytherapy: 77 single-lumen and 40 multicatheter devices. A subset of 12 patients treated with SAVI(®) had bed-to-skin spacing <7mm. All patients had Tis-2N0 ductal carcinoma with negative margins. A total dose of 34.0Gy in 10 fractions was delivered twice daily. Planning target volume was created using computed tomography-based three-dimensional planning with a 1.0-cm expansion of the lumpectomy cavity. Skin dose was measured dosimetrically, with skin constraints <125% of the prescription. Toxicities were graded, and patients were assessed at various intervals.

RESULTS

Of the patients treated with the multicatheter device, 0% (0/12) had their device pulled. At 2 weeks after treatment, fewer than 50% of the patients had skin toxicities of Grades 1-2, all of which resolved by 6 months. The cosmetic outcome was good to excellent at followup.

CONCLUSIONS

Multicatheter devices permit well-tolerated accelerated partial-breast irradiation in patients with tumor cavities near the skin surface for which the single-lumen device may not be appropriate.

Factors associated with optimal long-term cosmetic results in patients treated with accelerated partial breast irradiation using balloon-based brachytherapy

PURPOSE

To evaluate factors associated with optimal cosmetic results at 72 months for early-stage breast cancer patients treated with Mammosite balloon-based accelerated partial breast irradiation (APBI).

METHODS AND MATERIALS

A total of 1,440 patients (1,449 cases) with early-stage breast cancer undergoing breast-conserving therapy were treated with balloon-based brachytherapy to deliver APBI (34 Gy in 3.4-Gy fractions). Cosmetic outcome was evaluated at each follow-up visit and dichotomized as excellent/good (E/G) or fair/poor (F/P). Follow-up was evaluated at 36 and 72 months to establish long-term cosmesis, stability of cosmesis, and factors associated with optimal results.

RESULTS

The percentage of evaluable patients with excellent/good (E/G) cosmetic results at 36 months and more than 72 months were 93.3% (n = 708/759) and 90.4% (n = 235/260). Factors associated with optimal cosmetic results at 72 months included: larger skin spacing (p = 0.04) and T1 tumors (p = 0.02). Using multiple regression analysis, the only factors predictive of worse cosmetic outcome at 72 months were smaller skin spacing (odds ratio [OR], 0.89; confidence interval [CI], 0.80-0.99) and tumors greater than 2 cm (OR, 4.96, CI, 1.53-16.07). In all, 227 patients had both a 36-month and a 72-month cosmetic evaluation. The number of patients with E/G cosmetic results decreased only slightly from 93.4% at 3 years to 90.8% (p = 0.13) at 6 years, respectively.

CONCLUSIONS

APBI delivered with balloon-based brachytherapy produced E/G cosmetic results in 90.4% of cases at 6 years. Larger tumors (T2) and smaller skin spacing were found to be the two most important independent predictors of cosmesis.