Breast-Conserving Therapy is Associated with Improved Survival Without an Increased Risk of Locoregional Recurrence Compared with Mastectomy in Both Clinically Node-Positive and Node-Negative Breast Cancer Patients.

INTRODUCTION: Randomized trials demonstrated equivalent survival between breast-conserving surgery combined with radiotherapy (BCT) and mastectomy alone. Contemporary retrospective studies using pathological stage have reported improved survival with BCT. However, pathological information is unknown before surgery. To mimic real-world surgical decision-making, this study assesses oncological outcomes by using clinical nodal status. METHODS: Female patients aged 18-69 years who were treated with upfront BCT or mastectomy between 2006 and 2016 for T1-3N0-3 breast cancer were identified by using prospective, provincial database. The patients were divided into clinically node-positive (cN+) and node-negative (cN0) strata. Multivariable logistic regression was used to assess the effect of local treatment type on overall survival (OS), breast cancer-specific survival (BCSS), and locoregional recurrence (LRR). RESULTS: Of 13,914 patients, 8228 had BCT and 5686 had mastectomy. Mastectomy patients had higher-risk clinicopathological factors: pathologically positive axillary staging was 21% in BCT and 38% in mastectomy groups. Most patients received adjuvant systemic therapy. For cN0 patients, 7743 had BCT and 4794 had mastectomy. On multivariable analysis, BCT was associated with improved OS (hazard ratio [HR] 1.37, p < 0.001) and BCSS (HR 1.32, p < 0.001), whereas LRR was not different between the groups (HR 0.84, p = 0.1). For cN+ patients, 485 had BCT and 892 had mastectomy. On multivariable analysis, BCT was associated with improved OS (HR 1.46, p = 0.002) and BCSS (HR 1.44, p = 0.008), whereas LRR was not different between the groups (HR 0.89, p = 0.7). CONCLUSIONS: In the era of contemporary systemic therapy, BCT was associated with better survival than mastectomy, without an increased risk of locoregional recurrence for both cN0 and cN+ presentations.

Nipple margin assessment at the time of nipple-sparing mastectomy.

BACKGROUND: Documenting negative margins at the nipple-areolar complex (NAC) during nipple-sparing mastectomy (NSM) remains the standard, but how to achieve this and how to manage a positive margin is debated. We sought to review nipple margin assessments at our institution and to analyze the risk factors of a positive margin and rate of local recurrence. METHODS: Patients who underwent NSM between 2012 and 2018 were reviewed and divided into 3 groups based on indication - cancer, contralateral prophylactic mastectomy (CPM) and bilateral prophylactic mastectomy (BPM). RESULTS: Nipple-sparing mastectomies were performed on 337 patients; 72% for cancer, 20% for CPMs and 8% for BPMs. Nipple margin assessments were performed in 87.8% of patients; 10 patients (3.4%) had a positive margin, 7 of whom underwent NAC excision and 3 were managed with observation. CONCLUSION: As indications for NSM increase, assessment of nipple margin provides valuable information to manage the NAC in patients with cancer. The routine use of nipple margin biopsies in patients undergoing CPM and BPM may no longer be required, as rates of occult malignant disease are low with no positive biopsies. Further studies with larger sample sizes are needed.

Excision of breast fibroepithelial lesions: when is it still necessary?-A 10-year review of a regional centre.

PURPOSE: Fibroepithelial lesions (FEL) range from benign fibroadenoma (FA) to malignant phyllodes tumor (PT), but can be difficult to diagnose on core needle biopsy (CNB). This study assesses risk factors for phyllodes tumor (PT) and recurrence and whether a policy to excise FELs over 3 cm in size is justified. METHODS: Patients having surgery for FELs from 2009 to 2018 were identified. The association of clinical, radiology and pathological features with PT and recurrence were evaluated. Trend analysis was used to assess risk of PT based on imaging size. RESULTS: Of the 616 patients with FELs, 400 were identified as having FA on CNB and 216 were identified as having FEL with a comment of concern for phyllodes tumor (query PT, QPT). PT was identified in 107 cases; 28 had CNB of FA (7.0%), while 79 had QPT (36.6%). Follow-up was available for 86 with a mean of 56 months; six patients had recurrence of PT, all of whom had QPT on CNB. The finding of PT was associated with CNB of QPT, increasing age and size on multivariate logistic regression. All patients diagnosed with PT following CNB of FA had enlarging lesions with a mean size of 38.3 mm. CONCLUSIONS: Our data does not support routine excision of FELs based on size alone. All patients with QPT on CNB, regardless of size should consider excision due to high risk of PT and recurrence, and the decision to excise FAs to rule out PT should also consider whether the lesion is enlarging.

The Breast Cancer Patient Experience of Telemedicine During COVID-19.

BACKGROUND: The COVID-19 pandemic has seen major shifts in the delivery of health care across the world, including adoption of telemedicine. We present a survey of patient experience with telemedicine for the treatment of breast cancer. METHODS: A questionnaire designed to assess patient satisfaction with telemedicine was distributed to all patients who underwent surgery at the Providence Breast Centre (PBC) for breast cancer or benign/high-risk lesions with surgery follow-up dates between October 13 and December 31, 2020. Surveys were conducted via phone or at in-person follow-ups. RESULTS: A total of 123 of 172 (72%) eligible patients completed the survey; 85% of these patients enjoyed their telemedicine consultation, 93% found there was enough time for dialogue, 66% would choose to have a telemedicine consultation again, 79% would recommend telemedicine at PBC to a friend or family member, and 92% found Zoom© easy to use. When asked whether they prefer a telemedicine initial consultation over an in-person, 28% of patients agreed. When patients are analyzed according to their home address, those more than 10-km away from PBC prefer telemedicine over in-person appointments (37%) more often than those who live less than 10-km away (23%) (p = 0.045). CONCLUSIONS: Patients report a high level of satisfaction with telemedicine. It may be worthwhile to continue telemedicine beyond the pandemic era, due to its convenience, efficiency, and low-cost while keeping patients, physicians, and office staff safe. It also may be more useful in large geographic areas, such as British Columbia to increase access to care.

Immediate breast reconstruction in locally advanced breast cancer: is it safe?

PURPOSE: Immediate breast reconstruction (IBR) following mastectomy remains controversial for locally advanced breast cancer over concerns regarding recurrence and complications which may delay adjuvant therapies. This study aimed to compare the oncologic outcomes and surgical safety of IBR following mastectomy with mastectomy alone (MA) for locally advanced breast cancer. METHODS: All patients treated at the Providence Breast Center between 2012 and 2017 for biopsy-proven locally advanced breast cancer, AJCC (8th edition) clinical stages (IIB-IIIC), were included. Primary outcomes were overall survival (OS), disease-specific survival (DSS), and disease-free survival (DFS). Secondary outcomes included recurrence rate, adjuvant therapy use, and reoperation. RESULTS: 267 patients (112 IBR, 155 MA) were included. On average, IBR patients were younger (48.82 years vs 61.42 years, P < 0.001). Median study follow-up was 50.7 months. OS was higher among IBR patients (86.6% vs 73.5%, P < 0.05). However, no significant differences were found in DSS (87.5% vs 84.5%, P = 0.34), DFS (79.5% vs 78.7%, P = 0.55), local recurrence (0% vs 1.9%, P = 0.194), adjuvant therapy use (95.5% vs 91.6%, P = 0.155), or reoperation (1.8% vs 1.3%, P = 0.559). CONCLUSION: IBR is a safe option for patients with locally advanced breast cancer and does not negatively impact survival, cancer recurrence rates, and use of adjuvant therapy.

COVID-19 and breast cancer at a Regional Breast Centre: our flexible approach during the pandemic.

PURPOSE: In British Columbia (BC), there have been 2790 confirmed COVID-19 cases as of June 20, 2020. The aim of this project is to capture the effect of COVID-19 on the volume of surgery and adaptations to the surgical care of patients at a breast centre in BC. METHODS: All proven or suspected breast cancer cases treated with surgery between March 16, 2019 and April 30, 2019 and March 16, 2020 and April 30, 2020 through the Providence Breast Centre were included in this review. The date ranges in 2020 mark the early COVID-19 pandemic period in BC and the large shift in operating room access during this time. RESULTS: In 2019, 99 patients underwent surgery for proven breast cancer and 30 patients for suspected breast cancer. In 2020, 162 patients underwent surgery for breast cancer and 34 for suspected breast cancer. Wait times from core biopsy to surgery and surgery to oncology consultation were improved in 2020 with a reduction of core biopsy to surgery time from 58 to 28 days for patients seen during the pandemic. There was an increased use of regional anesthesia and same day discharge compared to 2019 with increases in regional anesthesia (41%-89%) and same day discharge (64%-86%) after adaptations to the pandemic were implemented. CONCLUSIONS: Changes such as improved access to telemedicine, timing for cancer surgeries, and safer anesthetic techniques in response to the pandemic will change breast cancer surgical care beyond the pandemic era. Centralization and team-based care is the way forward.

Sentinel Node Biopsy Should Not be Routine in Older Patients with ER-Positive HER2-Negative Breast Cancer Who Are Willing and Able to Take Hormone Therapy.

BACKGROUND: The SSO Choosing Wisely campaign recommended selective sentinel lymph node biopsy (SLNB) in clinically node-negative women aged ≥ 70 years with ER+ breast cancer. We sought to assess the association of SLNB positivity, adjuvant treatment, and survival in a population-based cohort. PATIENTS AND METHODS: Women aged ≥ 70 years treated for ER+ HER2- breast cancer between 2010 and 2016 were identified in our prospective provincial database. Overall survival (OS) and breast cancer-specific survival (BCSS) were assessed using Kaplan-Meier analysis. Multivariable logistic regression was used to assess the association of SLNB positivity with use of adjuvant treatments and survival outcomes. RESULTS: We identified 2662 patients who met study criteria. SLNB was positive in 25%. Increased use of chemotherapy (ChT), hormone therapy (HT), and radiotherapy (RT) was significantly associated with SLNB positivity. Five-year OS was 86%, and BCSS was 96% with median follow-up of 4.3 years. BCSS was worse with grade 3 disease (HR 4.1, 95% CI 2.1-8.1, p < 0.0001) and better with HT (HR 0.5 95% CI 0.3-0.9, p = 0.01). Patients with a positive SLNB treated without adjuvant therapy had lower BCSS (HR 3.2 95% CI 1.2-8.4, p = 0.017) than those with a negative SLNB, but patients with a positive SLNB treated with any combination of ChT, HT, and/or RT, had similar BCSS to those with a negative SLNB. CONCLUSIONS: BCSS in this population was excellent at 96%, and BCSS was similar with negative and positive SLNB when patients received HT. SLNB can be omitted in elderly patients willing to take HT.

Effects of High Anxiety Scores on Surgical and Overall Treatment Plan in Patients with Breast Cancer Treated with Neoadjuvant Therapy.

BACKGROUND: Patients with newly diagnosed breast cancer and high levels of anxiety often pursue more aggressive surgical interventions. The neoadjuvant treatment (NAT) setting could provide a window of opportunity to address patients' anxiety. However, the impact of anxiety on surgical decisions in the setting of NAT for breast cancer has not been previously studied. MATERIALS AND METHODS: A prospective database of patients with breast cancer treated with NAT at BC Cancer was used to identify patients treated with NAT and subsequent surgical resection. Patients with bilateral breast cancer or BRCA mutations or those referred to the hereditary cancer program were excluded. An anxiety score of 0-3 was assigned based on responses to the Edmonton Symptom Assessment System and Psychosocial Screen for Cancer. Clinicopathological information and treatment data were retrieved and cross-referenced between the low-anxiety (scores 0-1) and high-anxiety (scores 2-3) cohorts. RESULTS: From 2012 to 2016, 203 patients met eligibility criteria. Of these, 93 patients (45.8%) had low anxiety and 110 patients (54.2%) had high anxiety. Overall, 161 patients (79.3%) had locally advanced cancers; no differences in stage, grade, or biomarkers were found between the low- and high-anxiety cohorts. Patients with high self-reported anxiety at initial consultation were younger (mean 56 years vs. 60 years; p = .011) and more likely to undergo mastectomy for breast-conserving surgery-eligible disease and bilateral mastectomy for unilateral disease compared with those with low anxiety (37.3% vs. 18.3%; likelihood ratio 9.15; p = .002). No significant differences in treatment timelines were identified between the two cohorts. CONCLUSION: Patients with high anxiety at initial consultation were nine times more likely to undergo aggressive surgery compared with patients with low anxiety. These findings underscore the need for early identification of patients who may benefit from tailored supportive and educational services to address sources of anxiety and knowledge gaps. IMPLICATIONS FOR PRACTICE: The prevalence of anxiety among women with newly diagnosed breast cancer is being increasingly acknowledged. However, health care providers have not fully appreciated the impact of anxiety on the surgical management of patients with early-stage breast cancer. This study highlights the importance of self-reported anxiety on surgical management. The preoperative period provides a unique window of opportunity to address sources of anxiety and provide targeted educational materials over a period of 4-6 months, which may ultimately lead to less aggressive surgery when it is not needed.

Development and Prospective Validation of a Risk Calculator That Predicts a Low Risk Cohort for Atypical Ductal Hyperplasia Upstaging to Malignancy: Evidence for a Watch and Wait Strategy of a High-Risk Lesion.

BACKGROUND: Guidelines recommend surgical excision of atypical ductal hyperplasia (ADH) due to the concern of undersampling a potential malignancy on core needle biopsy (CNB). The purpose of this study was to determine clinical, radiological and pathological variables associated with ADH upstaging to cancer and to develop a predictive risk calculator capable of identifying women who have a low oncological risk of upstaging. METHODS: A prospectively collected database from a tertiary breast referral center was analyzed for women diagnosed with ADH on CNB between January 2013 to December 2017 who underwent surgical excision. CNB and surgical pathology reports were examined to determine rate of upstaging. The association between clinical, radiological and pathological variables were evaluated using regression analysis to determine predictors of ADH upstaging to cancer. Significant variables (p ≤ 0.05) identified on univariate analysis were assigned a score of "1" and were included in the ADH upstaging risk calculator. RESULTS: A total of 1986 patients underwent surgery for a high-risk lesion. We identified 318 (16.0%) patients who had ADH identified on their CNB who underwent surgery-of which 290 were included in our study. The upstage rate was 24.8%. Five variables were associated with upstaging and included in our calculator: (1) lesion > 5 mm on ultrasound; (2) lesion > 5 mm on mammogram; (3) one or more "high-risk" lesion(s) on CNB; (4) pathological suspicion for cancer and; (5) incomplete removal of calcifications on CNB. Patients with a score of 0 had a 2% risk of being upstaged to cancer and were deemed low risk with 17.2% of patients falling within this category. CONCLUSIONS: Patients with ADH on CNB can be stratified into a low oncological cohort who have a 2% risk of being upstaged to carcinoma. In the future, these select patients may be counselled and potentially offered observation as an alternative to surgery.

Risk of malignancy in papillary neoplasms of the breast.

PURPOSE: In recent years, routine excision of papillary neoplasms (PN) of the breast has been questioned and controversy exists over when excision is necessary. The aim of this study was to evaluate the upstage rate to malignancy of core needle biopsy (CNB) diagnosed PNs from multiple diagnostic centers in our area and to identify factors predictive of malignancy. METHODS: Patients presenting to our surgical center between 2013 and 2017 for excision of CNB PN were evaluated. The primary endpoint was upstage to malignancy. The association of age, diagnostic center where CNB performed, type of CNB, palpability, discharge, clinical exam size, imaging size, family history of breast cancer, and presence of atypia, as risk factors for upstaging to cancer were also evaluated. RESULTS: Of the 317 PN cases, 83 upstaged to malignancy following surgical excision. 77% of patients with CNB of Atypical PN upstaged, 39% of PN with concurrent atypical ductal hyperplasia, and 0% of PN with concurrent atypical lobular hyperplasia/flat epithelial atypia. Of the 206 non-atypical PNs on CNB, 3.4% upstaged to malignancy, but further review demonstrated a 1% upstage rate when atypia excluded. Factors found to be associated with malignancy included: older patient age, larger size, and presence of atypia. CONCLUSION: We recommend excision of PN with atypia, concurrent cancerous lesion, or radiologic-pathologic non-concordance, and serial imaging follow up may be considered for image detected PN, less than 1 cm, with no atypia.

Is microductectomy still necessary to diagnose breast cancer: a 10-year study on the effectiveness of duct excision and galactography.

PURPOSE: Patients with spontaneous nipple discharge (SND) who have neither clinically palpable masses nor evidence of disease on imaging with mammogram and/or ultrasound are traditionally investigated with galactogram and duct excision. As breast imaging improves, it has raised the question whether galactography and microductectomy are necessary to diagnose breast cancer. The purpose of this study was to determine the incidence of malignancy in patients presenting with SND who underwent microductectomy and to evaluate the utility of duct excision and galactography in patients whose initial clinical and radiological evaluation were negative. METHODS: A 10-year retrospective study was conducted in British Columbia's largest tertiary breast referral center examining the clinical, radiological and pathological results for all patients who underwent a microductectomy procedure for SND between 2008 and 2017. RESULTS: A total of 231 microductectomies were performed and the overall incidence of malignancy was 13% (n = 32). Following initial work up, 155 patients (67%) had only discharge on exam and no radiologically suspicious findings of malignant disease. Of these patients, 14% (n = 21) were diagnosed with cancer by duct excision. Galactography yielded a sensitivity and specificity of 63% and 36%, respectively (PPV 15% and NPV 85%). Lastly, we found that 3% of patients (n = 8) initially diagnosed with benign disease later developed breast cancer. CONCLUSIONS: Patients with SND should continue to be evaluated with microductectomy to prevent missing a breast cancer. Moreover, we do not recommend performing galactography for diagnosing breast cancer due to poor sensitivity and specificity though it may assist in preoperative planning.

Immediate Reconstruction Swing Room Scheduling Reduces Wait Times to Surgery and Increases Breast Reconstruction Rates.

BACKGROUND: Despite benefits in quality of life, patient satisfaction, overall healthcare costs, and number of surgeries, historically fewer than 30% of patients undergo immediate breast reconstruction following mastectomy for breast cancer. A paucity of qualified oncologic and plastic surgeons coupled with inefficient use of operating room (OR) resources presents challenges in offering immediate breast reconstruction in a timely manner. To address these challenges, an immediate reconstruction swing room (IRSW) program was developed. METHODS: IRSW scheduling leverages two concurrently running ORs, with the surgical oncologist and plastic surgeon moving between rooms to complete 2-4 combined mastectomy cases with immediate reconstruction, in addition to 1-2 independent cases, each operative day. The final year of traditional booking was compared with IRSW scheduling to assess wait times and reconstruction rates. RESULTS: Comparing the 2 years, fewer surgical breast cases were performed with IRSW scheduling (1250 vs. 1178), however the overall number of oncology cases increased from 735 (59%) to 857 (73%). The number of immediate reconstructions performed increased from 75 to 139 (p < 0.0001), which reflects a mean of 1.2 IR cases versus 2.9 combined cases in IRSW. Overall, this facilitated an increase in the rate of immediate reconstruction following therapeutic mastectomy from 35 to 49% (p = 0.0004) and decreased wait times from core biopsy to surgery from 70 to 52 days (p < 0.0001). CONCLUSIONS: A multidisciplinary model with optimized scheduling has the potential to improve resource utilization and access to breast cancer care.

Number of nodes in sentinel lymph node biopsy for breast cancer: Are surgeons still biased?

BACKGROUND AND OBJECTIVES: The purpose of this study was to assess the number of lymph nodes removed at SLNB, and what factors might bias a surgeon's decision to remove additional nodes. METHODS: A prospectively maintained database was reviewed. All patients that had SLNB for primary treatment of breast cancer between January 2012 and March 2016 were identified. Clinicopathologic factors were used to compare the number of LNs and rates of node positivity. RESULTS: One thousand six hundred and three patients were included. The average number of SLNs, non-SLNs, and total LNs was 2.53, 0.54, 3.08, respectively. Significantly more LNs were removed in age <40 versus age >40 (3.73, 3.04 P < 0.01), invasive versus DCIS (3.13, 2.73 P < 0.001), Grade III versus Grade II (3.42, 2.99 P < 0.01), T2 versus T1 (3.40, 2.96 P < 0.01), and ER- versus ER+ (3.45, 3.05 P < 0.05). SLN positivity was significantly higher (P < 0.05) in invasive versus DCIS (27%, 4%), T2 versus T1 (30%. 17%), Grade II versus Grade I (42%, 18%), and ILC versus IDC (38%, 26%). CONCLUSIONS: There was a significant difference in the number of lymph nodes removed at SLNB in certain groups however; node positivity was not necessarily higher in these groups. Surgeons must be cognizant of potential bias when performing SLNB.

Prospective surveillance and targeted physiotherapy for arm morbidity after breast cancer surgery: a pilot randomized controlled trial.

OBJECTIVE: To evaluate prospective surveillance and targeted physiotherapy (PSTP) compared to education (EDU) on the prevalence of arm morbidity and describe the associated program cost. DESIGN: Pilot randomized single-blinded controlled trial. SETTING: Urban with assessments and treatment delivered in hospitals. PARTICIPANTS: Women scheduled for breast cancer surgery. INTERVENTIONS: Participants were randomly assigned (1:1) to PSTP ( n = 21) or EDU ( n = 20) and assessed presurgery and 12 months postsurgery. All participants received usual care, namely, preoperative education and provision of an education booklet with postsurgical exercises. The PSTP group was monitored for arm morbidity every three months and referred for physiotherapy if arm morbidity was identified. The EDU group received three education sessions on nutrition, stress and fatigue management. MAIN OUTCOME MEASURES: Arm morbidity was based on changes in the surgical arm(s) from presurgery in four domains: (1) shoulder range of motion, (2) strength, (3) volume, and (4) upper body function. Complex arm morbidity indicated ≥2 domains impaired. Second, the cost of the PSTP program was described. RESULTS: At 12 months, 18 (49%) participants (10 PSTP and 8 EDU) had arm morbidity, with EDU participants presenting more complex arm morbidity compared to PSTP participants. PSTP participants attended 4.4 of 5 assessments with 90% retention. The PSTP program cost was $150 covered by the Health Care Provider and the Patient Out-of-Pocket Travel cost was CAN$40. CONCLUSION: Our results suggest that PSTP is feasible among women with breast cancer for early identification of arm morbidity. A larger study is needed to determine the cost and effectiveness benefits.

Axillary reverse mapping in breast cancer: a Canadian experience.

BACKGROUND: The aim of this study was to evaluate the axillary reverse lymphatic mapping (ARM) procedure for reducing the risk of arm lymphedema after breast cancer surgery. METHODS: The ARM procedure was carried out with a subareolar injection of technetium-99 sulfur colloid the morning of surgery, and a patent blue dye injection into the upper inner arm after anesthesia. RESULTS: Fifty-two women made up our study population. Thirty-seven patients underwent sentinel lymph node biopsy (SLNB) and 15 patients underwent an axillary lymph node dissection (ALND) for known nodal metastasis. The sentinel lymph node was identified in 36 of the 37 cases who underwent SLNB alone and in 12 of 15 patients who underwent on ALND. In 13 patients, both blue and radioactive lymph nodes or lymphatics were clearly identified (25%) and 5 patients had a clear crossover with nodes being both blue and hot. Only a single patient with crossover lymphatics had metastases present in their sentinel node. CONCLUSION: The ARM technique did not prevent identification of the SLN and we identified much greater crossover than reported. We had a single patient, who underwent a sentinel node biopsy, with mild arm lymphedema (1.9%) after 2 years of follow up.

Paget's disease of the breast: Presentation, treatment, and outcomes in a modern cohort.

BACKGROUND: Surgical management for Paget's disease (PD) of the breast is controversial. This study aims to assess outcomes of PD patients based on procedure type and determine the reliability of imaging in estimating disease extent. METHODS: A retrospective review analyzed clinicopathologic data of PD patients between 2009 and 2022. Pre-operative imaging size (PIS) was compared to post-operative pathology size (PPS) looking at concordance. RESULTS: Thirty patients had PD, 21 underwent total mastectomy (TM) and 9 breast conserving surgery (BCS). Seventeen patients (56.7 â€‹%) had a final diagnosis of invasive cancer (14 â€‹TM, 3 BCS), with no local recurrences. Only 6/19 (31.6 â€‹%) patients with positive findings on ultrasound/mammogram had concordance between PIS and PPS. There were no breast/chest wall recurrences with a median follow up of 35.9 months. CONCLUSION: Ultrasound and mammogram had poor concordance with pathological size. BCS is feasible in select patients. MRI may help guide management.

Breast conserving surgery combined with radiation therapy offers improved survival over mastectomy in early-stage breast cancer.

INTRODUCTION: Landmark trials established equivalent survival regardless of extent of breast surgery in early-stage breast cancer. However, recent studies suggest a survival advantage for breast conserving surgery (BCS) with radiotherapy (BCT). This study assesses the impact of type of surgery on overall survival (OS), breast cancer specific survival (BCSS) and local recurrence (LR) in a modern population-based cohort. METHODS: Female patients aged ≥18, pT1-2pN0, who had surgery between 2006 and 2016 were identified from Breast Cancer Outcome Unit prospective database. Neoadjuvant chemotherapy patients were excluded. Multivariable Cox regression was used to assess the effect of surgical procedure on OS, BCSS, and LR on cohort with complete data. RESULTS: BCT was performed in 8422 patients and TM in 4034 patients. The baseline characteristics differed between the groups. Mean follow up was 8.3 years. BCT was associated with increased OS HR 1.37, p < 0.001, BCSS survival HR 1.49, p < 0.001, and similar LR HR 1.00, p > 0.90. CONCLUSION: This study supports that in early-stage breast cancer, BCT has improved BCSS compared to TM without an increased risk of LR.