Margin Re-excision Research Articles

Mastectomy or Margin Re-excision? A Nomogram for Close/Positive Margins After Lumpectomy for DCIS.

Anatomic extent of ductal carcinoma in situ (DCIS) may be uncertain in spite of clinical, pathologic, and imaging data.Consequently close/positive margins are common with lumpectomy for DCIS and often lead to a challenge in deciding whether to perform a re-excision or mastectomy. From a single health system, we identified cases of lumpectomy for DCIS with close/positive margins who underwent re-excision for the purpose of constructing a nomogram. In total, 289 patients were available for analysis. The patients were randomly divided into two sets allocating 70% to the modeling and 30% to the validation set.A multivariable logistic regression model was used to estimate the probability of overall positive margin status using multiple clinicopathologic predictors.Nomogram validation included internal tenfold cross-validation, internal bootstrap validation, and external validation for which a concordance index was calculated to assess the external validity. Significant predictors of persistent positive margins from regression modeling included necrosis at diagnosis (non-comedo or comedo); DCIS not associated with calcifications on core biopsy; high-grade DCIS; progesterone receptor positivity; and number of positive margins at initial surgery.When subjected to internal validation, the nomogram achieved an uncorrected concordance index of 0.7332, a tenfold cross-validation concordance index of 0.6795, and a bootstrap-corrected concordance index of 0.6881. External validation yielded an estimated concordance index of 0.7095. Using clinical and pathologic variables from initial diagnosis and surgery for DCIS, this nomogram predicts persistent positive margins with margin re-excision, and may be a valuable tool in surgical decision-making.

TP8.1.10 Factors predicting residual disease on re-excision after breast conserving surgery

Abstract Introduction Breast conserving surgery is the standard of care for early breast cancer, however in a quarter of patients, satisfactory margins are not achieved, usually leading to re-excision. Residual disease is found in less than half of these re-excisions, leading to increased morbidity,poorer cosmesis and increased cost with no oncological benefit. Our study aimed to identify a group of patients with unsatisfactory margins but a low risk of residual disease, who may be able to avoid re-excision. Methods All patients from our unit undergoing re-excision for unsatisfactory margins after breast conserving surgery between January 2013 and October 2019 were identified. Pathological factors predicting residual disease were investigated using univariable and multivariable analysis. Results 220 patients were included. 90 (41%) had residual disease in the re-excision specimen. Residual disease was more likely in those having mastectomy than cavity shaves (61% vs 32%, p < 0.0001). Residual disease increased in a linear fashion with number of involved margins and with increasing tumour size. Tumour size <20mm (p = 0.045), a pathological to radiological tumour size ratio less than 1.5 (p < 0.0001) and disease-free cavity shaves taken at initial surgery (p = 0.041) were all significant predictors of a low chance of residual disease on multivariable analysis. Patients with all three factors had a 14% chance of residual disease. Conclusions More than half of patients undergo unnecessary re-excision, and patients with small, radiologically obvious tumours are less likely to have residual disease. The decision on re-excision should include these factors in addition to the margin status.

Comparison of Surgical and Oncological Outcomes between Chest Wall Perforator Flaps and Therapeutic Mammoplasty.

Background:Chest wall perforator flaps (CPF) and therapeutic mammoplasty (TM) are often done in patients with anticipated poor cosmetic outcome with level 1 breast conservation surgery. The aim of this study was to assess the complications and oncological outcomes between CPF and TM.Methods:Prospectively collected data of breast conservation surgery between September 2016 and January 2021 by a single surgeon were reviewed. Specific outcomes included complications needing intervention, re-excision and mastectomy rate, locoregional recurrence, and distant metastasis. Patients were followed up at 3 months and then every 12 months. Statistical analysis included chi-squared test and independent t test, and a P value of less than 0.05 was considered significant.Results:There was no statistically significant difference between CPF and TM with regard to patient characteristics except for BMI and bra cup size, which was significantly higher in the TM group. One patient who had TM returned to the operating room for a hematoma evacuation, and one patient who had CPF had fat grafting, for unsatisfactory cosmetic outcome. Five of the 30 patients having CPF had further re-excision surgery for inadequate margins, but none needed mastectomy, and four of the 43 patients having TM had further surgery (one had re-excision of margins and three had mastectomy) and this was not statistically significant (P = 0.346). There was no locoregional recurrence in CPF and TM groups after a median follow-up of 22 months and 25 months, respectively.Conclusion:There is no significant difference in early complications and oncological outcomes between CPF and TM.

Trichoblastoma mimicking basal cell carcinoma and the approach to its management: Case report.

Introduction and importanceTrichoblastoma is a benign and rare cutaneous lesion with striking resemblance to basal cell carcinoma. However, the course of the illness varies significantly from basal cell carcinoma. It usually takes a less malicious route and causes minimal harm to the patient,unlike basal cell carcinoma where it can be aggressive and requires additional radiotherapy. Therefore, being able to differentiate them from one another is crucial to properly set a management plan.Case presentationA 44-year-old Saudi male, diagnosed with basal cell carcinoma of the scalp in Dammam Medical Centre (DMC) and was referred to our hospital for re-excision of positive margins. Slide review of the histopathology samples in our hospital showed features consistent with trichoblastoma. This was further confirmed by a dermahistopathologist.Clinical discussionThis rare benign tumour has posed multiple challenges in the clinical setting as not enough studies were conducted in order to dictate a proper management course. However, current management approach to the majority of skin lesions rely on the histopathological subtype and surgical excision. Many benign and malignant dermatological entities may mimic basal cell carcinoma, and therefore misdiagnosis can lead to either unnecessary excision or delayed treatment of metastatic disease. It is important to request the proper investigations to ease the process of diagnosis and more importantly, the process of differentiation.ConclusionDifferentiating the two tumours from one another allows for the initiation of proper treatment early resulting in an improved prognosis for both lesions. The gold standard investigation to diagnose and differentiate between them is a surgical biopsy. Trichoblastoma typically has a favourable prognosis with a low incidence of recurrence or progression.

Maintaining Contour with a Three-dimensional Interstitial Tissue Marker in 134 Lumpectomies.

Background:Breast-conserving surgery (BCS) is meant to preserve the natural appearance of the breast; however, tissue volume deficits cannot always be compensated by soft tissue mobilization. A three-dimensional (3D) interstitial tissue marker (BioZorb) was designed to delineate the lumpectomy cavity for targeting boost irradiation, but an unexpected secondary benefit may be in guiding wound contraction and restoring contour to the lumpectomy bed. We analyze tissue volume excised at the time of lumpectomy as a function of device size selected.Methods:In total, 134 consecutive lumpectomy patients implanted with BioZorb between May 2015 and February 2020 were retrospectively analyzed for tissue volume excised, device size used, location, and re-operation rates, including explantation of the device.Results:An estimated 113 patients underwent device implantation at initial lumpectomy, and 21 at margin re-excision. Twenty-seven patients underwent re-excision, while 14 elected mastectomy for positive margins following insertion; 22 had the same device reimplanted. Mean lumpectomy volume was 79.0 cm3 (range 10.3–275.8 cm3) during the first implant procedure. Large-volume lumpectomies, averaging 136.5 cm3, were associated with selection of larger devices, which aided in restoring volume and maintaining breast contour. Three (2.2%) patients requested removal of the device.Conclusions:BioZorb implantation can be a safe and useful oncoplastic technique for restoring volume with BCS. Large-volume lumpectomies can be performed without contouring defects using the device. An unexpected secondary benefit of the device may be scaffolding for wound contraction.

Impalpable Breast Cancer and Service Delivery During the COVID-19 Pandemic – the Role of Radiofrequency Tag localization

Background: Radiofrequency tags are used to localize breast lesions for surgery. During the Covid-19 pandemic, these offered the flexibility of inserting the Tags days or weeks before surgery. This made logistics of planning theatres lists easier, especially with most of the lists having been moved off site.Methods: In the 7 weeks following the first lockdown in the UK, we reviewed all planned admissions for breast surgery looking at the types of surgery offered, type of localization used and assessed which cases would not have been able to go ahead had radiofrequency tags not been available.Results: Out of 85 planned admission, 83 had surgery, 11 were for re-excision of margins and 72 for their first breast surgery excision (mastectomy or breast conservation). Out of the 54 that had breast conserving surgery, 40 needed localization, out of whom 27 had radiofrequency tags. Looking at theatre order list and location of surgery, 20 out of the 27 would not have had their surgery had radiofrequency tags not been available, which is 50% of the patients needing localization.Conclusion: Radiofrequency tags are new devices used for breast lesion localization that offer a much-needed flexibility especially as seen during the Covid-19 pandemic.

Factors predicting residual disease on re-excision after breast conserving surgery

IntroductionBreast conserving surgery is the standard of care for early breast cancer, however in a quarter of patients, satisfactory margins are not achieved, usually leading to re-excision. Residual disease is found in less than half of these re-excisions, leading to increased morbidity, poorer cosmesis and increased cost, possibly with no oncological benefit. Our study aimed to identify a group of patients with unsatisfactory margins but a low risk of residual disease, who may be able to avoid re-excision. Methods and materialsAll patients from our unit undergoing re-excision for unsatisfactory margins after breast conserving surgery between January 2013 and October 2019 were identified. Pathological factors predicting residual disease were investigated using univariable and multivariable analysis. Results220 patients were included. 90 (41 %) had residual disease. Residual disease was more likely in those having mastectomy than cavity shaves (61 % vs 32 %, p < 0.0001). Residual disease increased in a linear fashion with number of involved margins and with increasing tumour size. Tumour size <20 mm (p = 0.045), a pathological to radiological tumour size ratio less than 1.5 (p < 0.0001) and disease-free cavity shaves taken at initial surgery (p = 0.041) were all independent predictors of a low chance of residual disease on multivariable analysis. Patients with all three factors had a 14 % chance of residual disease. ConclusionsMore than half of patients undergo potentially unnecessary re-excision, and patients with small, radiologically obvious tumours are less likely to have residual disease. The decision on re-excision should include these factors in addition to the margin status.

The Effect of Lumpectomy and Cavity Shave Margin Status on Recurrence and Survival in Breast-Conserving Surgery.

Cavity shave margins (CSMs) decrease rate of positive margins and need for re-excision. Recurrence data following breast-conserving surgery (BCS) are not always available in large cancer registries. We sought to define our recurrence and survival data in BCS with routine excision of CSMs. A single institution, 10-year retrospective review of breast cancer patients who underwent BCS with routine CSMs was conducted. Cavity shave margin technique was standard. Cox proportional hazard analyses and the Kaplan-Meier method were used to estimate recurrence and survival. Breast-conserving surgery with CSM was performed in 839 patients. Re-excision rate to achieve negative margins was 8.5%. Fifty-two patients (75%) underwent margin re-excision vs 18 patients (25%) underwent salvage mastectomy. Positive margin rate stratified by tumor histology was highest for invasive lobular carcinoma followed by mixed invasive ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS), followed by pure DCIS and lowest for IDC. Length of follow-up was (4.7 ± 2.6, years). Overall recurrence rate (locoregional and systemic) was 4.3%: highest in patients with negative lumpectomy margin but positive CSM (L-S+ = 15%) followed by positive lumpectomy and CSMs (L+S+ = 14%), followed by patients with positive lumpectomy margin but negative CSMs (L+S- = 13%) and lowest for negative lumpectomy and CSM (L-S- = 5%), (P = .0008). There was no difference in 5-year breast cancer-specific survival between the 4 subgroups: 96% for L-S-, 86.7% L-S+, 94.7% L+S+ and 90% L+S- (P = .094). Recurrence following BCS with CSMs can be stratified based on both lumpectomy and cavity shave margin positivity. Routine excision of CSMs allows identification of these patient subsets.

Comparative study of surgical and oncological outcomes in oncoplastic versus non oncoplastic breast-conserving surgery for breast cancer treatment

SummaryBackground: Oncoplastic surgery has been increasingly used in breast cancer treatment and allows the performance of breast-conserving surgery in cases of larger tumors with unfavorable location or tumor-breast disproportion. Purpose: To compare surgical and oncological outcomes of patients undergoing oncoplastic and nononcoplastic breast-conserving surgery. Methods: Retrospective cohort study with convenience sampling of 866 patients who consecutively underwent breast-conserving surgery from 2011 to 2015. Results: The mean follow-up was 50.4 months. Nononcoplastic breast conservation surgery was performed on 768 (88.7%) patients and oncoplastic surgery on 98 (11.3%) patients. Patients in the oncoplastic group were younger (p<0.0001) and most were premenopausal (p<0.0001). Comorbidities such as diabetes (p=0.003) and hypertension (p=0.0001) were less frequent in this population. Invasive carcinoma >2 cm (p<0.0001), multifocality (p=0.004), ductal in situ carcinoma (p=0.0007), clinically positive axilla (p=0.004), and greater weight of surgical specimens (p<0.0001) were more frequent in the oncoplastic group. A second surgery for margin re-excision was more frequently performed in the nononcoplastic group (p=0.027). There was more scar dehiscence in the oncoplastic group (p<0.001), but there was no difference in early major complications (p=0.854), conversion to mastectomy (p=0.92), or local recurrence (p=0.889). Conclusion: Although used for the treatment of larger and multifocal tumors, surgical re-excisions were performed less often in the oncoplastic group, and there was no increase in conversion to mastectomy or local recurrence. In spite of the higher rate of overall complications in the oncoplastic group, major complications were similar in both groups.

Bracketing with Multiple Radioactive Seeds to Achieve Negative Margins in Breast Conservation Surgery: Multiple Seeds in Breast Surgery

IntroductionBreast conservation surgery (BCS) is the treatment of choice for unifocal, early-stage breast cancer. The ability to offer BCS to a wider subset of patients, including those with multifocal/multicentric cancer as well as extensive ductal carcinoma in situ, has emerged over time, especially in those undergoing joint oncoplastic reconstruction and those treated with neoadjuvant therapy. However, localization techniques using multiple radioactive seeds for bracketing in this patient subset have not been validated. Materials and MethodsA single-institution retrospective review was conducted of all patients with breast cancer who underwent BCS, guided by multiple bracketed iodine I 125 radioactive seeds between January 2014 and April 2017. ResultsBracketing of breast cancer using 2 or more radioactive seeds was performed in 157 breasts in 156 patients. Negative margins were achieved in 124 of 157 (79%) breasts, including 33 cases (21%) that underwent targeted margin reexcision at the time of surgery after intraoperative, multidisciplinary margin assessment. Thirty-three cases (21%) resulted in close or positive margins, of which 11 (7%) and 10 (6.4%) underwent completion mastectomy or repeat lumpectomy, respectively. Twelve patients (7.6%) did not undergo reexcision. En bloc resection was successful in 134 of 157 (85.4%) lumpectomies. Eighty-nine percent of the procedures were coupled with oncoplastic reconstruction. ConclusionBracketing techniques using multiple radioactive seeds expands the indications for breast conservation therapy in patients who would have traditionally required mastectomy. Intraoperative margin assessment improves surgical and pathologic success. Larger defects created by multifocal resection are optimally managed in concert with oncoplastic reconstruction to minimize asymmetries and aesthetic defects.

A Multicentric Prospective Cohort Study of Modified Lateral Intercostal Artery Perforator Flap in Partial Breast Reconstruction.

Oncoplastic breast surgery is well established in many parts of the world and is gaining popularity in the rest of the world. The cornerstone in oncoplastic breast surgery is to respect oncological principles during cancer resection maintaining good aesthetic and cosmetic outcome. With the advancement in local, regional, and systemic treatment for breast cancer, survival has improved, and patients live longer. It is utmost essential to help our patients to maintain a good quality of life. Aesthetic and cosmetic outcomes have a significant impact on patient's psychosocial, emotional, and sexual well-being.Oncoplastic techniques have evolved over the last decade with the increasing use of perforator flaps to enable partial breast reconstruction. We report the findings of a prospective cohort study using modified lateral intercostal artery perforator in partial breast reconstruction. This modified technique offers a less visible scar and good access to the axilla without any need for repositioning the patient during the operative procedure. A retrospective review of a prospectively maintained database of patients who underwent partial breast reconstruction with a modified lateral intercostal artery perforator flap was carried out between July 2016 and January 2020 in 2 oncoplastic breast units. The study had local approval from the respective audit departments. Patient demographics, operative data, surgical complications, and outcomes were collected and analyzed. Forty-one patients underwent the procedure between July 2016 and January 2020. The median age of the population data was 58 years (interquartile range, 9 years). There were 10 active smokers (24.4%), and 3 patients had diabetes mellitus (7.3%). Overall, 3 patients (7.1%) developed seroma, 1 had a hematoma (2.4%), and 1 had a locoregional recurrence (2.4%). Two patients (4.9%) underwent margin re-excision for close margins. Most patients (92%) had the procedure carried out as day-case surgery. None of the patients developed wound infection, necrosis, or flap loss. The results were comparable across the 2 participating units. The data suggest that modified intercostal artery perforator flap is an excellent oncoplastic technique for volume replacement in partial breast reconstruction with a short learning curve and minimal perioperative morbidity.

Value of intraoperative frozen section analysis in re-excision margin evaluation in breast-conserving surgery for cancer: a single institution experience

Previous studies have demonstrated that in women with breast cancer treated with breast-conserving surgery (BCS), intraoperative frozen section analysis of lumpectomy margins results in a decrease in reoperation rates for margin control. However, the value of intraoperative frozen margin evaluation (FME) in re-excision margin analysis was not fully understood. We conducted a retrospective review of patients who underwent attempted breast-conserving surgery for breast cancer with routine intraoperative frozen margin evaluation at our institution between January 1998 and May 2016. The number of frozen margin evaluation was analyzed. We additionally analyzed factors associated with positive re-excised margins to identify correlations with patient characteristics. A total of 760 patients who underwent attempted breast-conserving surgery were routinely conducted intraoperative frozen margin evaluation, frozen sections were obtained from the initial margin only in 82.5% (n = 627), the initial margin as well as a one-time re-excision analysis in 15.8% (n = 120), or the initial margin and two or more re-excision analyses in 1.7% (n-13). Based on the results of frozen margin evaluation, 727 (95.6%) of the patients underwent breast-conserving surgery, while the remaining 33 (4.4%) converted to mastectomy. Among the patients who underwent breast-conserving surgery, 112 (15.4%) had an initial positive margin on a frozen margin evaluation, underwent one-time margin re-excision and achieved a margin-free status, while 1.6% underwent a second margin resection due to a positive result on the first re-excised margin. In total, 72.7% of the conversions to mastectomy were due to a positive initial margin. Univariate and multivariate analyses showed that patients with the ductal carcinoma in situ (DCIS) histological type were more likely to have repeatedly positive re-excised margins during breast-conserving surgery. Routine intraoperative frozen margin evaluation of re-excised margins provided only limited value in patients who underwent attempted breast-conserving surgery; this method may be beneficial in the subgroup of patients with the ductal carcinoma in situ histological type.

P099. Where angels fear to tread: Does surgical margin re-excision following breast conserving surgery increase the rate of local recurrence?

Introduction: Breast-conserving surgery (BCS) is the gold standard surgical treatment for early stage breast cancer. The margin status of the resection is an important prognostic factor for local recurrence after BCS. Surgical re-excision of margins as a second procedure can be an inexact science. The aim of our audit was to compare local recurrence rates following re-excision of margins with local recurrence rates following BCS only.

P062. The use of radiofrequency tag localization of impalpable breast cancers during the COVID-19 pandemic

Background: Radiofrequency (RF) Tags are new devices used to localize breast lesions for surgery. During the Covid-19 Pandemic these offered the flexibility to be inserted days or weeks before surgery, making the logistics of planning theatres lists much easier especially when most of our breast cancer surgery was moved off site. Materials and Methods: In the 7 weeks following the lockdown in the UK, we reviewed all the planned admissions for breast surgery looking at the types of surgery offered, type of localization used and assessed who wouldn't have had their surgery if RF tags were not available locally. Results: Out of 85 planned admission, 83 had surgery, 11 were for re-excision of margins and 72 for their first breast surgery excision (mastectomy or breast conservation). Out of the 54 that had BCS, 40 needed localization, out of these 27 had RF tags. Looking at theatre order list and the site that surgery was performed, 20 out of the 27, wouldn't have had their surgery if RF tags were not available, that is 50% of patients needing Localization. Conclusion: RF Tags are new devices used for breast lesion localization, like other similar new devices, they offer the flexibility of being inserted days or weeks before surgery making the logistics of theatre planning easier, offering a much-needed flexibility especially during the Covid19 Pandemic. This was approved as an Audit by NHS Grampian Clinical Governance Department

Risk Factors Associated to Residual Tumor in Re-excision for Positive Margins in Breast Conservative Surgery.

Breast conservative surgery (BCS) is an adequate treatment for patients with early breast cancer. Local recurrence is associated with diverse factors. Our objective was to evaluate risk factors associated with finding residual tumor in patients with positive margins in BCS. Observational retrospective study, including patients diagnosed with breast cancer undergoing BCS between 2000 and 2016. Clinicopathological and treatment variables were collected. Main outcome was the finding of residual tumor on re-excision. Positive margins were defined as tumor present on ink. Three hundred and six patients underwent BCS. Mean age was 57 ± 12.2years. Positive margins were found in 84 (27.4%) patients, 15 (4.9%) had unknown margin status, and 207 (67.6%) had negative margins. Seventy-eight patients from the positive margin group and 23 patients from the unknown/negative margin group were reintervened. Residual tumor was present in 41% of patients with positive margins and in 45% of patients with negative margins (P = .192). In univariate analysis, overweight (P = .04) and positive axillary lymph nodes (P = .02) were associated with residual tumor on re-excision. In multivariate analysis, postmenopausal status was a protective factor (HR .047, P = .30). Mean follow-up was 58.4months and mean local recurrence-free survival (LRFS) was 56.4months (.1-203.2), with no difference regarding margin status or residual tumor. Postmenopausal status was associated with a decreased rate of residual tumor in patients with positive margins. The presence of residual tumor on re-excision was not associated with a lower LRFS. These factors must be considered when positive margins are present in BCS.

Magnetic Seed Localization (Magseed) for excision of impalpable breast lesions-The North Wales experience.

The breast surgical community has faced huge challenges due to close working relationships with radiologists who are in short supply. Breast lesion localization is moving away from the traditional wire technique, which requires an on-site radiologist to support theater scheduling. In North Wales, the introduction of Magseed for impalpable breast lesion localization has facilitated theater scheduling in the absence of same day radiology presence. We audited our first 200 Magseed cases to assess the safety and efficacy of the technique, the ease of use, and patient experience. Data were entered prospectively into an excel data base relating to Magseed cases. Data collected included demographics, pre and postoperative lesion size, histology, margin positivity, and re-excision rates. Data were submitted in real time by the radiologist performing Magseed insertion to ascertain degree of difficulty. A PROMS questionnaire was designed and sent to patients undergoing Magseed vs wire localizations. Two hundred patients underwent Magseed-guided wide local excision between May 2018 and January 2020 across 2 district general hospital sites in North Wales. Histology: 69% IDC, 20% ILC, and 11% others. Mean preoperative size 12.3mm, postoperative size 19mm. Re-excision rate 15%. Re-excision for DCIS was significantly more likely than for invasive disease (p<0.0001). A significant difference was also observed between radiological mean preoperative tumor size estimate and actual histological tumor size in patients undergoing margin re-excision (p=0.000019). Wire-guided re-excision rate was 21% in the same unit. PROMs found the procedure well tolerated by patients. Surgeons and radiologists reported Magseed to be user-friendly with minimal learning curve. Magseed use for impalpable breast lesion localization is safe, user friendly, and well tolerated by patients. It produces favorable re-excision rates when compared to published figures for wire-guided excision. The presence of DCIS and preoperative radiological size underestimation was associated with margin re-excision.

Abstract PS15-19: Preoperative selection of patients with early-stage invasive breast cancer for intraoperative radiation therapy (IORT): A single-institution experience

Abstract Purpose/Objective: Intraoperative radiation therapy (IORT) is a form of accelerated partial breast irradiation (APBI) delivered at the time of lumpectomy for early-stage breast cancer. Upfront selection of patients based on favorable preoperative characteristics is important to achieve good outcomes. Here we present our single-institution experience in the management of invasive breast cancer with IORT. We focused on the classification of patient suitability for IORT by the American Society for Therapeutic Radiation Oncology (ASTRO) APBI consensus guidelines using preoperative and postoperative clinicopathologic factors, as well as treatment outcomes and recurrences. Materials/Methods: We reviewed our institutional prospective registry database (AAAJ8512) to identify patients with biopsy-proven invasive breast cancer treated with breast IORT between 9/2013 and 4/2020 using the Zeiss Intrabeam™. Patients received a single dose of 20Gy delivered to the lumpectomy cavity surface at the time of planned surgery. We excluded patients from analysis with prior radiation to the breast, or triple negative disease at initial diagnosis. We reviewed preoperative and postoperative clinicopathologic factors to determine each patient’s ASTRO APBI suitability (suitable, cautionary or unsuitable) based on the 2017 consensus guidelines. Results: 237 patients were treated with IORT for early stage breast cancer. Median age was 67 years (range 44-94 years). Median extent of disease by conventional imaging was 1.0 cm (range 0 - 3.0cm). 51/103 (49.5%) patients with heterogeneously or extremely dense breasts underwent a MRI preoperatively. Based on preoperative clinicopathologic characteristics, 191 (80.6%) patients were suitable according ASTRO APBI guidelines, 46 (19.4%) cautionary and no patients were unsuitable. APBI group suitability changed in 95 (40.1%) patients based on final pathology from the time of lumpectomy, summarized in Table 1. 17 (7.2%) patients underwent re-excision for close or positive margins. 39 (16.5%) patients received additional adjuvant whole breast radiotherapy including 10/18 (56%) of unsuitable patients. Of 212 (89.5%) patients who initiated hormone therapy (HT), 191 (80.6%) were compliant at last follow up. Median follow-up for all patients was 38.2 months (0.4 - 74.5). Five (2.1%) patients experienced ipsilateral breast tumor recurrence, 1 (0.4%) patient experienced new contralateral breast cancer, and 2 (1.6%) patients experienced distant recurrence with the median time to event of 27.8 months (range 6.3-50.4). Of the 5 patients with ipsilateral breast tumor recurrence, 2 (0.8%) were true local recurrences &amp;lt;2cm from the initial lumpectomy bed with the same histology as initial tumor, both cases were cautionary risk and one declined HT, 3 (1.3%) were new breast primaries occurring &amp;gt;2cm from lumpectomy bed with a different histology. Conclusion: Breast IORT is an attractive cost-effective option for women with early stage breast cancer, and our 3-year true local recurrence rate is 0.8%. Optimal patient selection is key based on preoperative characteristics. Patients who become unsuitable or cautionary for APBI based on final pathology should be considered for additional adjuvant therapy. Table 1ReasonASTRO APBI Pre-Op Suitability#SizeER (-)AgeT2ILCSuitable191Cautionary46114101122Unsuitable0ASTRO APBI Post-Op Suitability Change#SizeClose MarginsPositive MarginsLVIMultifocalILCEICSuitable to Cautionary7792023211124Suitable to Unsuitable12111Cautionary to Unsuitable624Abbreviations: ER = Estrogen Receptor; ILC = Invasive Lobular Carcinoma; LVI = Lymphovascular Invasion; EIC = Extensive Intraductal Component Citation Format: Andrea M Brown, Christine Chin, Eileen Connolly, Roshni Rao, Bret Taback, Lisa Wiechmann. Preoperative selection of patients with early-stage invasive breast cancer for intraoperative radiation therapy (IORT): A single-institution experience [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS15-19.

Abstract PS9-56: High compliance with choosing wisely breast procedures at a safety net hospital

Abstract The Choosing Wisely campaign has emerged recently in setting guidelines for surgical procedures of low utility and cost-ineffectiveness. Hospitals caring for underserved medical populations represent a unique opportunity to assess for quality of care and adherence to these guidelines. The Choosing Wisely campaign for breast surgery has highlighted: avoiding surgical re-excision for invasive cancer close to margins of excised breast tissue, avoiding double mastectomy in patients who have a single breast with cancer, avoidance of axillary lymph node dissection in women undergoing lumpectomy with limited nodal disease, and avoiding sentinel lymph node biopsy in patients ≥ 70 years of age with early stage breast cancer. Recent studies have shown variable adherence to these recommendations. In order to evaluate cost-effective surgery at our hospital serving a poorer patient population, we retrospectively analyzed patients who underwent surgery for breast cancer from 2015-2020. A total of 231 patients were identified. There were no patients who underwent re-excision for close margins of invasive cancer. Only 0.9% of patients (2/231) received contralateral mastectomy and only 1.6% of eligible patients (3/191) received axillary lymph node dissection instead of sentinel lymph node biopsy. Although 77.7% of patients ≥ 70 years of age with stage 1 hormone positive breast cancer (14/18) received sentinel lymph node biopsy, there was a downward trend during 2015 to 2020 from 100% to 50% of eligible patients receiving sentinel lymph node biopsy. De-implementation of traditional surgical practices, deemed as low-value care, towards newer cost-effective guidelines are achievable even at community hospitals serving a low socioeconomic community while preserving patient outcome and avoiding overtreatment. By avoiding overtreatment, cost savings can be achieved which allow for social distributive justice amongst breast cancer patients by ensuring careful utilization of scarce health economic resources. Citation Format: Annie Tang, Colin Mooney, Shannon Ugarte, Kevin Knopf, Amal Khoury. High compliance with choosing wisely breast procedures at a safety net hospital [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS9-56.

The INTEND 1 randomized controlled trial of duct endoscopy as an indicator of margin excision in breast conservation surgery.

With early detection, breast conservation surgery with adequate surgical margins is the standard of care. The aim of this study was to evaluate the use of pre-operative duct endoscopy (DE) to target surgical resection, improve adequate margins and reduce re-excision operations. Women with DCIS, stage I and II breast cancer suitable for breast conservation were randomized to DE-assisted wide local excision versus standard wide local excision (without DE). The primary endpoint was margin re-excision rates between the two groups. Secondary end points were: (i) volume differences of the surgical specimen; (ii) whether an extensive in situ component (EIC) influenced successful DE-guided resection. 78 women were randomized: 44 patients to no-DE and 34 patients to the DE group. The median age was 59 (49-65) and 56 (48-64) years in the two groups respectively with mean follow-up of 9.1 (4.2-11.1) years. There were 23 positive findings in 17 women in 30 successful DE procedures (17/30 = 56.7%). The surgical specimen volume, no-DE (17 [IQR 10-29] cm3) and DE 20 [IQR 12-28] cm3), did not differ, p = 0.377. The overall re-excision rate was 20/78 (26%), 9 (20%) and 11 (32% in the no-DE and DE groups, respectively, p = 0.233. This randomized clinical trial was limited by incomplete accrual. DE did not contribute to improved margin excision rates whether a target lesion was visualized or not. The presence of EIC did not improve efficacy of DE.

Management and outcomes of phyllodes tumours - 10 year experience.

Phyllodes tumours represent 0.3-1% of breast tumours, typically presenting in women aged 35-55 years. They are classified into benign, borderline and malignant grades and exhibit a spectrum of features. There is significant debate surrounding the optimal management of phyllodes tumour, particularly regarding appropriate margins. This is a retrospective review of a prospectively maintained database of patients who underwent surgical management for phyllodes tumours in a single tertiary referral centre from 2007-2017. Patient demographics, tumour characteristics, surgical treatment and follow-up data were analysed. Tumour margins were classified as positive (0mm), close (≤2mm) and clear (>2mm). A total of 57 patients underwent surgical excision of a phyllodes tumour. The Mean age was 37.7 years (range: ages 14-91) with mean follow-up of 38.5 months (range: 0.5-133 months). There were 44 (77%) benign, 4 (7%) borderline and 9 (16%) malignant phyllodes cases. 54 patients had breast conserving surgery (BCS) and 3 underwent mastectomy. 30 (53%) patients underwent re-excision of margins. The final margin status was clear in 32 (56%), close in 13 (23%) and positive in 12 (21%). During follow-up, 4 patients were diagnosed with local recurrence (2 malignant, 1 borderline and 1 benign pathology on recurrence samples). There are no clear guidelines for the surgical management and follow-up of phyllodes tumours. This study suggests that patients with malignant phyllodes and positive margins are more likely to develop local recurrence. There is a need for large prospective studies to guide the development of future guidelines.