Omitting Axillary Dissection in Breast Cancer with Sentinel-Node Metastases

BACKGROUND

Trials evaluating the omission of completion axillary-lymph-node dissection in patients with clinically node-negative breast cancer and sentinel-lymph-node metastases have been compromised by limited statistical power, uncertain nodal radiotherapy target volumes, and a scarcity of data on relevant clinical subgroups.

METHODS

We conducted a noninferiority trial in which patients with clinically node-negative primary T1 to T3 breast cancer (tumor size, T1, ≤20 mm; T2, 21 to 50 mm; and T3, >50 mm in the largest dimension) with one or two sentinel-node macrometastases (metastasis size, >2 mm in the largest dimension) were randomly assigned in a 1:1 ratio to completion axillary-lymph-node dissection or its omission (sentinel-node biopsy only). Adjuvant treatment and radiation therapy were used in accordance with national guidelines. The primary end point was overall survival. We report here the per-protocol and modified intention-to-treat analyses of the prespecified secondary end point of recurrence-free survival. To show noninferiority of sentinel-node biopsy only, the upper boundary of the confidence interval for the hazard ratio for recurrence or death had to be below 1.44.

RESULTS

Between January 2015 and December 2021, a total of 2766 patients were enrolled across five countries. The per-protocol population included 2540 patients, of whom 1335 were assigned to undergo sentinel-node biopsy only and 1205 to undergo completion axillary-lymph-node dissection (dissection group). Radiation therapy including nodal target volumes was administered to 1192 of 1326 patients (89.9%) in the sentinel-node biopsy-only group and to 1058 of 1197 (88.4%) in the dissection group. The median follow-up was 46.8 months (range, 1.5 to 94.5). Overall, 191 patients had recurrence or died. The estimated 5-year recurrence-free survival was 89.7% (95% confidence interval [CI], 87.5 to 91.9) in the sentinel-node biopsy-only group and 88.7% (95% CI, 86.3 to 91.1) in the dissection group, with a country-adjusted hazard ratio for recurrence or death of 0.89 (95% CI, 0.66 to 1.19), which was significantly (P<0.001) below the prespecified noninferiority margin.

CONCLUSIONS

The omission of completion axillary-lymph-node dissection was noninferior to the more extensive surgery in patients with clinically node-negative breast cancer who had sentinel-node macrometastases, most of whom received nodal radiation therapy. (Funded by the Swedish Research Council and others; SENOMAC ClinicalTrials.gov number, NCT02240472.).

Current clinical practice in the management of phyllodes tumors of the breast: an international cross-sectional study among surgeons and oncologists

PURPOSE

Phyllodes tumors of the breast are rare fibroepithelial lesions that are classified as benign, borderline or malignant. There is little consensus on best practice for the work-up, management, and follow-up of patients with phyllodes tumors of the breast, and evidence-based guidelines are lacking.

METHODS

We conducted a cross-sectional survey of surgeons and oncologists with the aim to describe current clinical practice in the management of phyllodes tumors. The survey was constructed in REDCap and distributed between July 2021 and February 2022 through international collaborators in sixteen countries across four continents.

RESULTS

A total of 419 responses were collected and analyzed. The majority of respondents were experienced and worked in a university hospital. Most agreed to recommend a tumor-free excision margin for benign tumors, increasing margins for borderline and malignant tumors. The multidisciplinary team meeting plays a major role in the treatment plan and follow-up. The vast majority did not consider axillary surgery. There were mixed opinions on adjuvant treatment, with a trend towards more liberal regiments in patients with locally advanced tumors. Most respondents preferred a five-year follow-up period for all phyllodes tumor types.

CONCLUSIONS

This study shows considerable variation in clinical practice managing phyllodes tumors. This suggests the potential for overtreatment of many patients and the need for education and further research targeting appropriate surgical margins, follow-up time and a multidisciplinary approach. There is a need to develop guidelines that recognize the heterogeneity of phyllodes tumors.

Effectiveness of Single vs Multiple Doses of Prophylactic Intravenous Antibiotics in Implant-Based Breast Reconstruction: A Randomized Clinical Trial

IMPORTANCE

Multiple-dose antibiotic prophylaxis is widely used to prevent infection after implant-based breast reconstruction despite the lack of high-level evidence regarding its clinical benefit.

OBJECTIVE

To determine whether multiple-dose antibiotic prophylaxis is superior to single-dose antibiotic prophylaxis in preventing surgical site infection (SSI) after implant-based breast reconstruction.

DESIGN, SETTING, AND PARTICIPANTS

This prospective, multicenter, randomized clinical superiority trial was conducted at 7 hospitals (8 departments) in Sweden from April 25, 2013, to October 31, 2018. Eligible participants were women aged 18 years or older who were planned to undergo immediate or delayed implant-based breast reconstruction. Follow-up time was 12 months. Data analysis was performed from May to October 2021.

INTERVENTIONS

Multiple-dose intravenous antibiotic prophylaxis extending over 24 hours following surgery, compared with single-dose intravenous antibiotic. The first-choice drug was cloxacillin (2 g per dose). Clindamycin was used (600 mg per dose) for patients with penicillin allergy.

MAIN OUTCOMES AND MEASURES

The primary outcome was SSI leading to surgical removal of the implant within 6 months after surgery. Secondary outcomes were the rate of SSIs necessitating readmission and administration of intravenous antibiotics, and clinically suspected SSIs not necessitating readmission but oral antibiotics.

RESULTS

A total of 711 women were assessed for eligibility, and 698 were randomized (345 to single-dose and 353 to multiple-dose antibiotics). The median (range) age was 47 (19-78) years for those in the multiple-dose group and 46 (25-76) years for those in the single-dose group. The median (range) body mass index was 23 (18-38) for the single-dose group and 23 (17-37) for the multiple-dose group. Within 6 months of follow-up, 30 patients (4.3%) had their implant removed because of SSI. Readmission for intravenous antibiotics because of SSI occurred in 47 patients (7.0%), and 190 women (27.7%) received oral antibiotics because of clinically suspected SSI. There was no significant difference between the randomization groups for the primary outcome implant removal (odds ratio [OR], 1.26; 95% CI, 0.69-2.65; P = .53), or for the secondary outcomes readmission for intravenous antibiotics (OR, 1.18; 95% CI, 0.65-2.15; P = .58) and prescription of oral antibiotics (OR, 0.72; 95% CI, 0.51-1.02; P = .07). Adverse events associated with antibiotic treatment were more common in the multiple-dose group than in the single-dose group (16.4% [58 patients] vs 10.7% [37 patients]; OR, 1.64; 95% CI, 1.05-2.55; P = .03).

CONCLUSIONS AND RELEVANCE

The findings of this randomized clinical trial suggest that multiple-dose antibiotic prophylaxis is not superior to a single-dose regimen in preventing SSI and implant removal after implant-based breast reconstruction but comes with a higher risk of adverse events associated with antibiotic treatment.

TRIAL REGISTRATION

EudraCT 2012-004878-26.

Patient-reported outcomes one year after positive sentinel lymph node biopsy with or without axillary lymph node dissection in the randomized SENOMAC trial

Introduction

This report evaluates whether health related quality of life (HRQoL) and patient-reported arm morbidity one year after axillary surgery are affected by the omission of axillary lymph node dissection (ALND).

Methods

The ongoing international non-inferiority SENOMAC trial randomizes clinically node-negative breast cancer patients (T1-T3) with 1–2 sentinel lymph node (SLN) macrometastases to completion ALND or no further axillary surgery. For this analysis, the first 1181 patients enrolled in Sweden and Denmark between March 2015, and June 2019, were eligible. Data extraction from the trial database was on November 2020. This report covers the secondary outcomes of the SENOMAC trial: HRQoL and patient-reported arm morbidity. The EORTC QLQ-C30, EORTC QLQ-BR23 and Lymph-ICF questionnaires were completed in the early postoperative phase and at one-year follow-up. Adjusted one-year mean scores and mean differences between the groups are presented corrected for multiple testing.

Results

Overall, 976 questionnaires (501 in the SLN biopsy only group and 475 in the completion ALND group) were analysed, corresponding to a response rate of 82.6%. No significant group differences in overall HRQoL were identified. Participants receiving SLN biopsy only, reported significantly lower symptom scores on the EORTC subscales of pain, arm symptoms and breast symptoms. The Lymph-ICF domain scores of physical function, mental function and mobility activities were significantly in favour of the SLN biopsy only group.

Conclusion

One year after surgery, arm morbidity is significantly worse affected by ALND than by SLN biopsy only. The results underline the importance of ongoing attempts to safely de-escalate axillary surgery.

Trial registration

The trial was registered at clinicaltrials.gov prior to initiation (https://clinicaltrials.gov/ct2/show/NCT 02240472).

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Omission of ALND significantly reduces patient-reported arm morbidity.

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SLNB versus ALND results in significant less pain and better physical function.

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HRQoL is not affected by de-escalated axillary surgery.

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Complaints from axillary surgery are evaluated with patient-reported outcomes.

False-negative rate in the extended prospective TATTOO trial evaluating targeted axillary dissection by carbon tattooing in clinically node-positive breast cancer patients receiving neoadjuvant systemic therapy

PURPOSE

In clinically node-positive breast cancer patients receiving neoadjuvant systemic therapy (NST), nodal metastases can be initially marked and then removed during surgical axillary staging. Marking methods vary significantly in terms of feasibility and cost. The purpose of the extended TATTOO trial was to report on the false-negative rate (FNR) of the low-cost method carbon tattooing.

METHODS

The international prospective single-arm TATTOO trial included clinically node-positive breast cancer patients planned for NST from November 2017 to January 2021. For the present analysis, patients who received both the targeted procedure with or without an additional sentinel lymph node (SLN) biopsy and a completion axillary lymph node dissection (ALND) were selected. Primary endpoint was the FNR.

RESULTS

Out of 172 included patients, 149 had undergone a completion ALND. The detection rate for the tattooed node was 94.6% (141 out of 149). SLN biopsy was attempted in 132 out of 149 patients with a detection rate of 91.7% (121 out of 132). SLN and tattooed node were identical in 58 out of 121 individuals (47.9%). The combined procedure, i.e. targeted axillary dissection (TAD) was successful in 147 of 149 cases (98.7%). Four out of 65 patients with a clinically node-negative status after NST had a negative TAD but metastases on ALND, corresponding to a FNR of 6.2%. All false-negative TAD procedures were performed in the first 2 years of the trial (2018-2019, p = 0.022).

CONCLUSION

Carbon tattooing is a feasible marking method for TAD with a high detection rate and an acceptably low FNR. The TATTOO trial was preregistered as prospective trial before initiation at the University of Rostock, Germany (DRKS00013169).

Effect of radiotherapy on expanders and permanent implants in immediate breast reconstruction: long-term surgical and patient-reported outcomes in a large multicentre cohort

BACKGROUND

Current evidence for the effects of radiotherapy (RT) on implant-based immediate breast reconstruction (IBR) is limited by short follow-up and lack of patient-reported outcomes (PROs). It is central to integrate long-term comprehensive outcome data into the preoperative decision-making process. The aim of the present study was to determine long-term surgical outcomes and PROs in relation to RT after implant-based IBR.

METHODS

This was a longitudinal cohort study of PRO data obtained in surveys conducted in 2012 and 2020 using the BREAST-Q questionnaire. All women undergoing therapeutic mastectomy and implant-based IBR between 1 January 2007 and 31 December 2011 at four breast centres in Stockholm, Sweden, were identified. The endpoint was implant removal owing to surgical complications or patient preference.

RESULTS

Median follow-up was 120 (range 1-171) months. After 754 IBRs in 729 women, implant removal occurred in 128 (17 per cent): 34 of 386 (8.8 per cent) in the no-RT group, 20 of 64 (31.3 per cent) in the group with previous RT, and 74 of 304 (24.3 per cent) in the postoperative RT group (P < 0.001). Implant removal was because of surgical complications in 60 instances (7.9 per cent), and patient preference in 68 (9.0 per cent). The BREAST-Q response rate was 72.2 per cent. Women with previous RT scored lower than those without RT on all scales, apart from psychosocial well-being. Women with postoperative RT scored lower only on physical well-being. No scores in the two RT groups had deteriorated between the survey time points, whereas satisfaction with breasts and overall outcome had decreased in the no-RT group.

CONCLUSION

Although RT was significantly associated with higher implant removal rates, PROs remained stable over 8 years despite irradiation.

Effect of Immediate Implant-Based Breast Reconstruction After Mastectomy With and Without Acellular Dermal Matrix Among Women With Breast Cancer: A Randomized Clinical Trial

IMPORTANCE

The use of acellular dermal matrix (ADM) in implant-based breast reconstructions (IBBRs) is established practice. Existing evidence validating ADMs proposed advantages, including improved cosmetics and more single-stage IBBRs, is lacking.

OBJECTIVE

To evaluate whether IBBR with ADM results in fewer reoperations and increased health-related quality of life (HRQoL) compared with conventional IBBR without ADM.

DESIGN, SETTING, AND PARTICIPANTS

This was an open-label, multicenter, randomized clinical trial of women with primary breast cancer who planned for mastectomy and immediate IBBR, with a 2-year follow-up for all participants. Participants were enrolled at 5 breast cancer units in Sweden and the United Kingdom between 2014 and May 2017. Exclusion criteria included previous radiotherapy and neo-adjuvant chemotherapy. Data were analyzed until August 2017.

INTERVENTIONS

Participants were allocated to immediate IBBR with or without ADM.

MAIN OUTCOMES AND MEASURES

The primary trial end point was number of reoperations at 2 years. HRQoL, a secondary end point, was measured as patient-reported outcome measures using 3 instruments from the European Organization for Research and Treatment of Cancer Quality of life Questionnaire.

RESULTS

From start of enrollment on April 24, 2014, to close of trial on May 10, 2017, a total of 135 women were enrolled (mean [SD] age, 50.4 [9.5] years); 64 were assigned to have an IBBR procedure with ADM and 65 to the control group who had IBBR without ADM. There was no statistically significant difference between groups for the primary outcome. Of 129 patients analyzed at 2-year follow-up, 44 of 64 (69%) had at least 1 surgical event in the ADM group vs 43 of 65 (66%) in the control group. In the ADM group, 31 patients (48%) had at least 1 reoperation on the ipsilateral side vs 35 (54%) in the control group. The overall number of reoperations on the ipsilateral side were 42 and 43 respectively. Within the follow-up time of 24 months, 9 patients (14%) in the ADM group had the implant removed compared with 7 (11%) in the control group. We found no significant mean differences in postoperative patient-reported HRQoL domains, including perception of body image (mean difference, 3; 99% CI, -11 to 17; P = .57) and satisfaction with cosmetic outcome (mean difference, 8; 99% CI, -6 to 20; P = .11).

CONCLUSIONS AND RELEVANCE

Immediate IBBR with ADM did not yield fewer reoperations compared with conventional IBBR without ADM, nor was IBBR with ADM superior in terms of HRQoL or patient-reported cosmetic outcomes. Patients treated for breast cancer contemplating ADM-supported IBBR should be informed about the lack of evidence validating ADM's suggested benefits.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02061527.

Survival in breast cancer patients with a delayed DIEP flap breast reconstruction after adjustment for socioeconomic status and comorbidity

Purpose

Overall survival in breast cancer patients receiving a delayed deep inferior epigastric perforator (DIEP) flap breast reconstruction is better than in those without delayed breast reconstruction. This study aimed at determining the impact of socioeconomic status (SES) and comorbidity on these observations.

Materials and methods

This matched cohort study included all consecutive women undergoing a delayed DIEP flap reconstruction at Karolinska University Hospital, Sweden, between 1999 and 2013. Controls had not received any delayed breast reconstruction and were relapse-free after a corresponding follow-up interval. Matching was by year of and age at mastectomy, tumour stage and lymph node status. Charlson Comorbidity Index (CCI) and socioeconomic data were obtained from national registers. Associations with breast cancer-specific (BCSS) and overall survival (OS) were investigated by Kaplan-Meier survival estimates and Cox proportional hazard regression analysis.

Results

Women in the DIEP group (N = 254) more often continued education after primary school (88.6% versus 82.6%, P = 0.026), belonged to the high-income group (76.0% versus 63.1%, P < 0.001), were in a partnership (57.1% versus 55.7%, P = 0.024) and healthier (median CCI 1.00 (range 0–13) versus 2.00 (range 0–16), P = 0.021) than the control group (N = 729). After adjustment for tumour and treatment factors, SES and comorbidity, OS remained significantly better for the DIEP group than the control group (HR 2.27, 95% CI 1.44–3.55).

Conclusion

Women with a delayed DIEP flap reconstruction are a subgroup of higher socioeconomic status and better health. Higher survival estimates for the DIEP group persisted after adjusting for those differences, suggesting the presence of further unmeasured covariates.

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Women with a delayed DIEP flap reconstruction have a higher socioeconomic status.

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They also have less comorbidity than women with no delayed reconstruction.

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Superior survival in DIEP patients is not eliminated by adjustments for such differences.

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Unmeasured selection to the reconstructive process may explain observed survival differences.

Long-term prognosis in breast cancer is associated with residual disease after neoadjuvant systemic therapy but not with initial nodal status

BACKGROUND

This follow-up analysis of a Swedish prospective multicentre trial had the primary aim to determine invasive disease-free (IDFS), breast cancer-specific (BCSS) and overall survival (OS) rates, and their association with axillary staging results before and after neoadjuvant systemic therapy for breast cancer.

METHODS

Women who underwent neoadjuvant systemic therapy for clinically node-positive (cN+) or -negative (cN0) primary breast cancer between 2010 and 2015 were included. Patients had a sentinel lymph node biopsy before and/or after neoadjuvant systemic therapy, and all underwent completion axillary lymph node dissection. Follow-up was until February 2019. The main outcome measures were IDFS, BCSS and OS. Univariable and multivariable Cox regression analyses were used to identify independent factors associated with survival.

RESULTS

The study included a total of 417 women. Median follow-up was 48 (range 7-114) months. Nodal status after neoadjuvant systemic therapy, but not before, was significantly associated with crude survival: residual nodal disease (ypN+) resulted in a significantly shorter 5-year OS compared with a complete nodal response (ypN0) (83·3 versus 91·0 per cent; P = 0·017). The agreement between breast (ypT) and nodal (ypN) status after neoadjuvant systemic therapy was high, and more so in patients with cN0 tumours (64 of 66, 97 per cent) than those with cN+ disease (49 of 60, 82 per cent) (P = 0·005). In multivariable analysis, ypN0 (hazard ratio 0·41, 95 per cent c.i. 0·22 to 0·74; P = 0·003) and local radiotherapy (hazard ratio 0·23, 0·08 to 0·64; P = 0·005) were associated with improved IDFS, and triple-negative molecular subtype with worse IDFS.

CONCLUSION

The present findings underline the prognostic significance of nodal status after neoadjuvant systemic therapy. This confirms the clinical value of surgical axillary staging after neoadjuvant systemic therapy.

Omitting completion axillary lymph node dissection after detection of sentinel node micrometastases in breast cancer: first results from the prospective SENOMIC trial

BACKGROUND

Completion axillary lymph node dissection has been abandoned widely among patients with breast cancer and sentinel lymph node micrometastases, based on evidence from prospective RCTs. Inclusion in these trials has been subject to selection bias, with patients undergoing mastectomy being under-represented. The aim of the SENOMIC (omission of axillary lymph node dissection in SENtinel NOde MICrometases) trial was to confirm the safety of omission of axillary lymph node dissection in patients with breast cancer and sentinel lymph node micrometastases, and including patients undergoing mastectomy.

METHODS

The prospective SENOMIC multicentre cohort trial enrolled patients with breast cancer and sentinel lymph node micrometastases who had breast-conserving surgery or mastectomy at one of 23 Swedish hospitals between October 2013 and March 2017. No completion axillary lymph node dissection was performed. The primary endpoint was event-free survival, with a trial accrual target of 452 patients. Survival proportions were based on Kaplan-Meier survival estimates.

RESULTS

The trial included 566 patients. Median follow-up was 38 (range 7-67) months. The 3-year event-free survival rate was 96.2 per cent, based on 26 reported breast cancer recurrences, including five isolated axillary recurrences. The unadjusted 3-year event-free survival rate was higher than anticipated, but differed between patients who had mastectomy and those who underwent breast-conserving surgery (93.8 versus 97.8 per cent respectively; P = 0.011). Patients who underwent mastectomy had significantly worse tumour characteristics. On univariable Cox proportional hazards regression analysis, patients who had mastectomy without adjuvant radiotherapy had a significantly higher risk of recurrence than those who underwent breast-conserving surgery (hazard ratio 2.91, 95 per cent c.i. 1.25 to 6.75).

CONCLUSION

After 3 years, event-free survival was excellent in patients with breast cancer and sentinel node micrometastases despite omission of axillary lymph node dissection. Long-term follow-up and continued enrolment of patients having mastectomy, especially those not receiving adjuvant radiotherapy, are of utmost importance.

Carbon tattooing for targeted lymph node biopsy after primary systemic therapy in breast cancer: prospective multicentre TATTOO trial

Background

Several techniques for targeted lymph node biopsy in patients with node-positive breast cancer receiving primary systemic therapy are in use, each with their inherent advantages and disadvantages. The aim of the TATTOO trial was to evaluate the feasibility and accuracy of carbon tattooing of positive lymph nodes as a method for targeted lymph node biopsy avoiding radiation exposure, high costs, and preoperative localization procedures.

Methods

Patients with initially cT1–4c cN1–3 cM0 invasive breast cancer were included in this prospective multicentre trial. Before initiation of primary systemic therapy, a carbon suspension was injected into the most suspicious axillary lymph node. Targeted lymph node biopsy was performed in all patients after completion of primary systemic therapy. Additional sentinel lymph node biopsy was done in those with axillary downstaging, and completion axillary lymph node dissection in patients still presenting with suspicious lymph nodes.

Results

A total of 118 patients were included and 110 were eligible for data analysis. The detection rate for the targeted lymph node was 93.6 per cent (103 of 110), and the sentinel lymph node was identical to the targeted lymph node in 60 per cent. The false-negative rate for the combination of targeted and sentinel node lymph node biopsy (targeted axillary dissection) was 9 per cent.

Conclusion

Targeted axillary dissection after carbon tattooing is associated with a high detection rate, an acceptable false-negative rate, and appears feasible for clinical use even in healthcare settings with limited resources.

Quality of life and patient satisfaction after implant-based breast reconstruction with or without acellular dermal matrix: randomized clinical trial

Background

Acellular dermal matrix (ADM) in implant‐based breast reconstructions (IBBRs) aims to improve cosmetic outcomes. Six‐month data are presented from a randomized trial evaluating whether IBBR with ADM provides higher health‐related quality of life (HRQoL) and patient‐reported cosmetic outcomes compared with conventional IBBR without ADM.

Methods

In this multicentre open‐label RCT, women with breast cancer planned for mastectomy with immediate IBBR in four centres in Sweden and one in the UK were allocated randomly (1 : 1) to IBBR with or without ADM. HRQoL, a secondary endpoint, was measured as patient‐reported outcome measures (PROMs) using three validated instruments (EORTC‐QLQC30, QLQ‐BR23, QLQ‐BRR26) at baseline and 6 months.

Results

Between 24 April 2014 and 10 May 2017, 135 women were enrolled, of whom 64 with and 65 without ADM were included in the final analysis. At 6 months after surgery, patient‐reported HRQoL, measured with generic QLQ‐C30 or breast cancer‐specific QLQ‐BR23, was similar between the groups. For patient‐reported cosmetic outcomes, two subscale items, cosmetic outcome (8·66, 95 per cent c.i. 0·46 to 16·86; P = 0·041) and problems finding a well‐fitting bra (−13·21, −25·54 to −0·89; P = 0·038), yielded higher scores in favour of ADM, corresponding to a small to moderate clinical difference. None of the other 27 domains measured showed any significant differences between the groups.

Conclusion

IBBR with ADM was not superior in terms of higher levels of HRQoL compared with IBBR without ADM. Although two subscale items of patient‐reported cosmetic outcomes favoured ADM, the majority of cosmetic items showed no significant difference between treatments at 6 months. Registration number: NCT02061527 ( www.clinicaltrials.gov).

The generalisability of randomised clinical trials: an interim external validity analysis of the ongoing SENOMAC trial in sentinel lymph node-positive breast cancer

Purpose

None of the key randomised trials on the omission of axillary lymph node dissection (ALND) in sentinel lymph-positive breast cancer have reported external validity, even though results indicate selection bias. Our aim was to assess the external validity of the ongoing randomised SENOMAC trial by comparing characteristics of Swedish SENOMAC trial participants with non-included eligible patients registered in the Swedish National Breast Cancer Register (NKBC).

Methods

In the ongoing non-inferiority European SENOMAC trial, clinically node-negative cT1–T3 breast cancer patients with up to two sentinel lymph node macrometastases are randomised to undergo completion ALND or not. Both breast-conserving surgery and mastectomy are eligible interventions. Data from NKBC were extracted for the years 2016 and 2017, and patient and tumour characteristics compared with Swedish trial participants from the same years.

Results

Overall, 306 NKBC cases from non-participating and 847 NKBC cases from participating sites (excluding SENOMAC participants) were compared with 463 SENOMAC trial participants. Patients belonging to the middle age groups (p = 0.015), with smaller tumours (p = 0.013) treated by breast-conserving therapy (50.3 versus 47.1 versus 65.2%, p < 0.001) and less nodal tumour burden (only 1 macrometastasis in 78.8 versus 79.9 versus 87.3%, p = 0.001) were over-represented in the trial population. Time trends indicated, however, that differences may be mitigated over time.

Conclusions

This interim external validity analysis specifically addresses selection mechanisms during an ongoing trial, potentially increasing generalisability by the time full accrual is reached. Similar validity checks should be an integral part of prospective clinical trials.

Trial registration: NCT 02240472, retrospective registration date September 14, 2015 after trial initiation on January 31, 2015

Do clinical trials truly mirror their target population? An external validity analysis of national register versus trial data from the Swedish prospective SENOMIC trial on sentinel node micrometastases in breast cancer

Purpose

Increasing evidence suggests that completion axillary lymph node dissection (ALND) may be omitted in breast cancer patients with limited axillary nodal metastases. However, the representativeness of trial participants for the original clinical practice population, and thus, the generalizability of published trials have been questioned. We propose the use of background data from national registers as a means to assess whether trial participants mirror their target population and to strengthen the generalizability and implementation of trial outcomes.

Methods

The Swedish prospective SENOMIC trial, omitting a completion ALND in breast cancer patients with sentinel lymph node micrometastases, reached full target accrual in 2017. To assess the generalizability of trial results for the target population, a comparative analysis of trial participants versus cases reported to the Swedish National Breast Cancer Register (NKBC) was performed.

Results

Comparing 548 trial participants and 1070 NKBC cases, there were no significant differences in age, tumor characteristics, breast surgery, or adjuvant treatment. Only the mean number of sentinel lymph nodes with micrometastasis per individual was lower in trial participants than in register cases (1.06 vs. 1.09, p = 0.037).

Conclusions

Patients included in the SENOMIC trial are acceptably representative of the Swedish breast cancer target population. There were some minor divergences between trial participants and the NKBC population, but taking these into consideration, upcoming trial outcomes should be generalizable to breast cancer patients with micrometastases in their sentinel lymph node biopsy.

Breast-conserving surgery followed by whole-breast irradiation offers survival benefits over mastectomy without irradiation

Background

The prognostic equivalence between mastectomy and breast‐conserving surgery (BCS) followed by radiotherapy was shown in pivotal trials conducted decades ago. Since then, detection and treatment of breast cancer have improved substantially and recent retrospective analyses point towards a survival benefit for less extensive breast surgery. Evidence for the association of such survival data with locoregional recurrence rates is largely lacking.

Methods

The Swedish Multicentre Cohort Study prospectively included clinically node‐negative patients with breast cancer who had planned sentinel node biopsy between 2000 and 2004. Axillary lymph node dissection was undertaken only in patients with sentinel node metastases. For the present investigation, adjusted survival analyses were used to compare patients who underwent BCS and postoperative radiotherapy with those who received mastectomy without radiotherapy.

Results

Of 3518 patients in the Swedish Multicentre Cohort Study, 2767 were included in the present analysis; 2338 had BCS with postoperative radiotherapy and 429 had mastectomy without radiotherapy. Median follow‐up was 156 months. BCS followed by whole‐breast irradiation was superior to mastectomy without irradiation in terms of both overall survival (79·5 versus 64·3 per cent respectively at 13 years; P < 0·001) and breast cancer‐specific survival (90·5 versus 84·0 per cent at 13 years; P < 0·001). The local recurrence rate did not differ between the two groups. The axillary recurrence‐free survival rate at 13 years was significantly lower after mastectomy without irradiation (98·3 versus 96·2 per cent; P < 0·001).

Conclusion

The present data support the superiority of BCS with postoperative radiotherapy over mastectomy without radiotherapy. The axillary recurrence rate differed significantly, and could be one contributing factor in a complex explanatory model.

Radiotherapy to lower axilla key?

Risk of recurrence and death in patients with breast cancer after delayed deep inferior epigastric perforator flap reconstruction

Background

Postmastectomy reconstruction using a deep inferior epigastric perforator (DIEP) flap is increasingly being performed in patients with breast cancer. The procedure induces extensive tissue trauma, and it has been hypothesized that the release of growth factors, angiogenic agonists and immunomodulating factors may reactivate dormant micrometastasis. The aim of the present study was to estimate the risk of breast cancer recurrence in patients undergoing DIEP flap reconstruction compared with that in patients treated with mastectomy alone.

Methods

Each patient who underwent delayed DIEP flap reconstruction at Karolinska University Hospital, Sweden, between 1999 and 2013, was compared with up to four controls with breast cancer who did not receive a DIEP flap. The control patients were selected using incidence density matching with respect to age, tumour and nodal status, neoadjuvant therapy and year of mastectomy. The primary endpoint was breast cancer‐specific survival. Survival analysis was carried out using Kaplan–Meier survival estimates and Cox proportional hazard regression analysis.

Results

The analysis included 250 patients who had 254 DIEP flap reconstructions and 729 control patients. Median follow‐up was 89 and 75 months respectively (P = 0·053). Breast cancer recurrence developed in 50 patients (19·7 per cent) in the DIEP group and 174 (23·9 per cent) in the control group (P = 0·171). The 5‐year breast cancer‐specific survival rate was 92·0 per cent for patients with a DIEP flap and 87·9 per cent in controls (P = 0·032). Corresponding values for 5‐year overall survival were 91·6 and 84·7 per cent (P < 0·001). After adjustment for tumour and patient characteristics and treatment, patients without DIEP flap reconstruction had significantly lower overall but not breast cancer‐specific survival.

Conclusion

The present findings do not support the hypothesis that patients with breast cancer undergoing DIEP flap reconstruction have a higher rate of breast cancer recurrence than those who have mastectomy alone.

Deep inferior epigastric perforator is safe

Abstract P4-13-14: Risk of recurrence and death in breast cancer patients after delayed deep inferior epigastric perforator flap reconstruction

PURPOSE

Post-mastectomy reconstruction using the deep inferior epigastric perforator (DIEP) flap is increasingly performed in breast cancer patients. The procedure induces large tissue trauma and it has been hypothesized that the release of growth factors, angiogenic agonists and immunomodulating factors may reactivate dormant micrometastasis. The aim of our study was to contrast the risk of breast cancer recurrence in patients undergoing DIEP reconstruction to patients treated with mastectomy alone.

PATIENTS AND METHODS

We conducted a retrospective nested case-control study. Cases were defined as breast cancer patients operated with delayed DIEP reconstruction at Karolinska University Hospital, Sweden, between 1999-2013. Three controls, defined as breast cancer patients operated with conventional mastectomy without delayed reconstruction, were matched to each case based on age, tumour stage and year of mastectomy. The primary endpoint was breast cancer-specific survival. Survival analysis was carried out by Kaplan–Meier survival estimates and Cox proportional hazard regression analysis.

RESULTS

In all, 254 cases and 729 controls were included and had a median follow up of 134 and 122 months, respectively (p=0.004). Breast cancer recurrence occurred in 50 (19.7%) cases and 174 (23.9%) controls, respectively (p=0.171). Ten-year breast cancer-specific survival was 90.7% for cases and 85.2% in controls (p=0.067). The corresponding figures for 10-year overall survival was 89.6% and 80.0%, respectively (p&lt;0.001). Higher tumor stage and positive axillary lymph nodes, but not DIEP reconstruction, were independent risk factors for death due to breast cancer.

CONCLUSION

Our findings did not support the hypothesis that breast cancer patients undergoing DIEP reconstruction would have a higher rate of breast cancer recurrence than patients undergoing mastectomy alone.

Citation Format: Adam H, Docherty Skogh A-C, Edsander Nord Å, Schultz I, Gahm J, Hall P, Frisell J, Halle M, de Boniface J. Risk of recurrence and death in breast cancer patients after delayed deep inferior epigastric perforator flap reconstruction [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-13-14.

Intra-tumor heterogeneity in breast cancer has limited impact on transcriptomic-based molecular profiling

Background

Transcriptomic profiling of breast tumors provides opportunity for subtyping and molecular-based patient stratification. In diagnostic applications the specimen profiled should be representative of the expression profile of the whole tumor and ideally capture properties of the most aggressive part of the tumor. However, breast cancers commonly exhibit intra-tumor heterogeneity at molecular, genomic and in phenotypic level, which can arise during tumor evolution. Currently it is not established to what extent a random sampling approach may influence molecular breast cancer diagnostics.

Methods

In this study we applied RNA-sequencing to quantify gene expression in 43 pieces (2-5 pieces per tumor) from 12 breast tumors (Cohort 1). We determined molecular subtype and transcriptomic grade for all tumor pieces and analysed to what extent pieces originating from the same tumors are concordant or discordant with each other. Additionally, we validated our finding in an independent cohort consisting of 19 pieces (2-6 pieces per tumor) from 6 breast tumors (Cohort 2) profiled using microarray technique. Exome sequencing was also performed on this cohort, to investigate the extent of intra-tumor genomic heterogeneity versus the intra-tumor molecular subtype classifications.

Results

Molecular subtyping was consistent in 11 out of 12 tumors and transcriptomic grade assignments were consistent in 11 out of 12 tumors as well. Molecular subtype predictions revealed consistent subtypes in four out of six patients in this cohort 2. Interestingly, we observed extensive intra-tumor genomic heterogeneity in these tumor pieces but not in their molecular subtype classifications.

Conclusions

Our results suggest that macroscopic intra-tumoral transcriptomic heterogeneity is limited and unlikely to have an impact on molecular diagnostics for most patients.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3815-2) contains supplementary material, which is available to authorized users.

Breast cancer in young women and prognosis: How important are proliferation markers?

AIM

Compared to middle-aged women, young women with breast cancer have a higher risk of systemic disease. We studied expression of proliferation markers in relation to age and subtype and their association with long-term prognosis.

METHODS

Distant disease-free survival (DDFS) was studied in 504 women aged <40 years and 383 women aged ≥40 years from a population-based cohort. Information on patient characteristics, treatment and follow-up was collected from medical records. Tissue microarrays were produced for analysis of oestrogen receptor, progesterone receptor (PR), Her2, Ki-67 and cyclins.

RESULTS

Young women with luminal tumours had significantly higher expression of Ki-67 and cyclins. Proliferation markers were prognostic only within this subtype. Ki-67 was a prognostic indicator only in young women with luminal PR+ tumours. The optimal cut-off for Ki-67 varied by age. High expression of cyclin E1 conferred a better DDFS in women aged <40 years with luminal PR- tumours (hazard ratio [HR] 0.47 [0.24-0.92]). Age <40 years was an independent risk factor of DDFS exclusively in women with luminal B PR+ tumours (HR 2.35 [1.22-4.50]). Young women with luminal B PR- tumours expressing low cyclin E1 had a six-fold risk of distant disease compared with luminal A (HR 6.21 [2.17-17.6]).

CONCLUSIONS

The higher expression of proliferation markers in young women does not have a strong impact on prognosis. Ki-67 is only prognostic in the subgroup of young women with luminal PR+ tumours. The only cyclin adding prognostic value beyond subtype is cyclin E1. Age is an independent prognostic factor only in women with luminal B PR+ tumours.

Estrogen Receptor β as a Therapeutic Target in Breast Cancer Stem Cells

Background

Breast cancer cells with tumor-initiating capabilities (BSCs) are considered to maintain tumor growth and govern metastasis. Hence, targeting BSCs will be crucial to achieve successful treatment of breast cancer.

Methods

We characterized mammospheres derived from more than 40 cancer patients and two breast cancer cell lines for the expression of estrogen receptors (ERs) and stem cell markers. Mammosphere formation and proliferation assays were performed on cells from 19 cancer patients and five healthy individuals after incubation with ER-subtype selective ligands. Transcriptional analysis was performed to identify pathways activated in ERβ-stimulated mammospheres and verified using in vitro experiments. Xenograft models (n = 4 or 5 per group) were used to study the role of ERs during tumorigenesis.

Results

We identified an absence of ERα but upregulation of ERβ in BSCs associated with phenotypic stem cell markers and responsible for the proliferative role of estrogens. Knockdown of ERβ caused a reduction of mammosphere formation in cell lines and in patient-derived cancer cells (40.7%, 26.8%, and 39.1%, respectively). Gene set enrichment analysis identified glycolysis-related pathways (false discovery rate < 0.001) upregulated in ERβ-activated mammospheres. We observed that tamoxifen or fulvestrant alone was insufficient to block proliferation of patient-derived BSCs while this could be accomplished by a selective inhibitor of ERβ (PHTPP; 53.7% in luminal and 45.5% in triple-negative breast cancers). Furthermore, PHTPP reduced tumor initiation in two patient-derived xenografts (75.9% and 59.1% reduction in tumor volume, respectively) and potentiated tamoxifen-mediated inhibition of tumor growth in MCF7 xenografts.

Conclusion

We identify ERβ as a mediator of estrogen action in BSCs and a novel target for endocrine therapy.

Survival and axillary recurrence following sentinel node-positive breast cancer without completion axillary lymph node dissection: the randomized controlled SENOMAC trial

Background

The role of axillary lymph node dissection (ALND) has increasingly been called into question among patients with positive sentinel lymph nodes. Two recent trials have failed to show a survival difference in sentinel node-positive breast cancer patients who were randomized either to undergo completion ALND or not. Neither of the trials, however, included breast cancer patients undergoing mastectomy or those with tumors larger than 5 cm, and power was debatable to show a small survival difference.

Methods

The prospective randomized SENOMAC trial includes clinically node-negative breast cancer patients with up to two macrometastases in their sentinel lymph node biopsy. Patients with T1-T3 tumors are eligible as well as patients prior to systemic neoadjuvant therapy. Both breast-conserving surgery and mastectomy, with or without breast reconstruction, are eligible interventions. Patients are randomized 1:1 to either undergo completion ALND or not by a web-based randomization tool. This trial is designed as a non-inferiority study with breast cancer-specific survival at 5 years as the primary endpoint. Target accrual is 3500 patients to achieve 80% power in being able to detect a potential 2.5% deterioration of the breast cancer-specific 5-year survival rate. Follow-up is by annual clinical examination and mammography during 5 years, and additional controls after 10 and 15 years. Secondary endpoints such as arm morbidity and health-related quality of life are measured by questionnaires at 1, 3 and 5 years.

Discussion

Several large subgroups of breast cancer patients, such as patients undergoing mastectomy or those with larger tumors, have not been included in key trials; however, the use of ALND is being questioned even in these groups without the support of high-quality evidence. Therefore, the SENOMAC Trial will investigate the need of completion ALND in case of limited spread to the sentinel lymph nodes not only in patients undergoing any breast surgery, but also in neoadjuvantly treated patients and patients with larger tumors.

Trial registration

NCT 02240472, retrospective registration date September 14, 2015 after trial initiation on January 31, 2015.

Swedish prospective multicenter trial on the accuracy and clinical relevance of sentinel lymph node biopsy before neoadjuvant systemic therapy in breast cancer

Purpose

The timing of sentinel lymph node biopsy (SLNB) in the context of neoadjuvant systemic therapy (NAST) in breast cancer is still controversial. SLNB before NAST has been evaluated in few single-institution studies in which axillary lymph node dissection (ALND), however, was commonly not performed in case of a negative SLNB. We investigated the potential clinical relevance of SLNB before NAST by performing ALND in all patients after NAST.

Methods

This national multicenter trial prospectively enrolled clinically node-negative breast cancer patients planned for NAST at 13 recruiting Swedish hospitals between October 2010 and December 2015. SLNB before NAST was followed by ALND after NAST in all individuals. Repeat SLNB after NAST was encouraged but not mandatory.

Results

SLNB before NAST was performed in 224 patients. The identification rate was 100% (224/224). The proportion of patients with a negative SLNB before NAST but positive axillary lymph nodes after NAST was 7.4% (nine of 121 patients, 95% CI 4.0–13.5). Among those with a positive SLNB before NAST, 23.2% (86/112) had further positive lymph nodes after NAST.

Conclusions

In clinically node-negative patients, SLNB before NAST is highly reliable. With this sequence, ALND and regional radiotherapy can be safely omitted in patients with a negative SLNB provided good clinical response to NAST. Additionally, SLNB-positive patients upfront will receive correct nodal staging unaffected by NAST and be consequently offered adjuvant locoregional treatment according to current guidelines pending the results of ongoing randomized trials.

Abstract P2-03-03: Molecular differences between screen-detected and interval breast cancers are largely explained by PAM50 subtypes

Purpose:Interval breast cancer is of clinical interest as it exhibits an aggressive phenotype and evades detection by screening mammography. A comprehensive picture of somatic changes that drive tumors to become symptomatic in the screening interval can improve understanding of the biology underlying these aggressive tumors.

Experimental design:Initiated in April 2013, Clinical Sequencing of Cancer in Sweden (Clinseq) is a scientific and clinical platform for the genomic profiling of cancer. The breast cancer pilot study consisted of women diagnosed with breast cancer between 2001-2012 in the Stockholm/Gotland regions. A subset of 318 breast tumors were sequenced, of which 113 were screen-detected and were 60 interval cancers.We applied targeted deep-sequencing of cancer-related genes, low-pass whole-genome sequencing and RNA-sequencing technology to characterize somatic differences in the genomic and transcriptomic architecture by interval cancer status. Mammographic density and PAM50 molecular subtypes were considered.

Results:In the crude analyses, TP53, PPP1R3A, and KMT2B were significantly more frequently mutated in interval cancers than in screen-detected cancers. Acquired somatic copy number aberrations with a frequency difference of at least 15% between the two groups included gains in 17q23-q25.3 and losses in 16q24.2. Gene expression analysis identified 447 significantly differentially expressed genes, of which 120 were replicated in an independent microarray dataset. After adjusting for PAM50, most differences were no longer significant.

Conclusions: Molecular differences by interval cancer status were observed, but they were largely explained by PAM50 subtypes. This work offer new insights into the biological differences between the two tumor groups.

Translational relevance: Although screen-detected cancers are biologically distinct from interval cancers in terms of somatic mutations, copy number aberrations and gene expression, most of the differences are no longer significant after adjusting for breast cancer intrinsic subtypes (PAM50). We also show that the molecular differences appear to form a spectrum from less aggressive (screen-detected) to more aggressive (interval) manifestations of the disease, which can be characterized by PAM50 subtypes, namely, luminal A, luminal B, HER2-enriched and basal-like, in that order. This work clarifies the picture on what type of breast cancer we are likely to identify through population-based screening, and what type of cancer we are likely to miss. Current knowledge of PAM50 subtype-specific risk factors need to be expanded as our findings might influence how we screen women with a higher risk of basal-like breast cancer for example, beyond known risk groups BRCA1 mutation carriers and women of African-American descent.

Citation Format: Czene K, Ivansson E, Klevebring D, Tobin NP, Lindström LS, Holm J, Prochazka G, Hilliges C, Palmgren J, Törnberg S, Humphreys K, Hartman J, Frisell J, Rantalainen M, Lindberg J, Hall P, Bergh J, Grönberg H, Li J. Molecular differences between screen-detected and interval breast cancers are largely explained by PAM50 subtypes [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-03-03.

Ten-year report on axillary recurrence after negative sentinel node biopsy for breast cancer from the Swedish Multicentre Cohort Study

BACKGROUND

The omission of axillary lymph node dissection (ALND) in patients with breast cancer with a negative finding on sentinel node biopsy (SNB) has reduced arm morbidity substantially. Early follow-up reports have shown the rate of axillary recurrence to be significantly lower than expected, with a median false-negative rate of 7 per cent for SNB. Long-term follow-up is needed as recurrences may develop late.

METHODS

The Swedish Multicentre Cohort Study included 3518 women with breast cancer and a clinically negative axilla, in whom SNB was planned. ALND was performed only in patients with sentinel node metastasis. Twenty-six centres contributed to enrolment between September 2000 and January 2004. The primary endpoint was the axillary recurrence rate and the secondary endpoint was breast cancer-specific survival, calculated using Kaplan-Meier survival estimates.

RESULTS

Some 2216 sentinel node-negative patients with 2237 breast cancers were analysed. The median follow-up time was 126 (range 0-174) months. Isolated axillary recurrence was found in 35 patients (1·6 per cent). High histological grade and multifocal tumours were risk factors for axillary recurrence, whereas the removal of more than two sentinel nodes decreased the risk. Fourteen (40 per cent) of 35 patients died as a consequence of axillary recurrence.

CONCLUSION

The risk of axillary recurrence remains lower than expected after a negative finding on SNB at 10-year follow-up. Axillary recurrences may occur long after primary surgery, and lead to a significant risk of breast cancer death.

Sequencing-based breast cancer diagnostics as an alternative to routine biomarkers

Sequencing-based breast cancer diagnostics have the potential to replace routine biomarkers and provide molecular characterization that enable personalized precision medicine. Here we investigate the concordance between sequencing-based and routine diagnostic biomarkers and to what extent tumor sequencing contributes clinically actionable information. We applied DNA- and RNA-sequencing to characterize tumors from 307 breast cancer patients with replication in up to 739 patients. We developed models to predict status of routine biomarkers (ER, HER2,Ki-67, histological grade) from sequencing data. Non-routine biomarkers, including mutations in BRCA1, BRCA2 and ERBB2(HER2), and additional clinically actionable somatic alterations were also investigated. Concordance with routine diagnostic biomarkers was high for ER status (AUC = 0.95;AUC(replication) = 0.97) and HER2 status (AUC = 0.97;AUC(replication) = 0.92). The transcriptomic grade model enabled classification of histological grade 1 and histological grade 3 tumors with high accuracy (AUC = 0.98;AUC(replication) = 0.94). Clinically actionable mutations in BRCA1, BRCA2 and ERBB2(HER2) were detected in 5.5% of patients, while 53% had genomic alterations matching ongoing or concluded breast cancer studies. Sequencing-based molecular profiling can be applied as an alternative to histopathology to determine ER and HER2 status, in addition to providing improved tumor grading and clinically actionable mutations and molecular subtypes. Our results suggest that sequencing-based breast cancer diagnostics in a near future can replace routine biomarkers.

Complementary use of scintimammography with 99m-Tc-MIBI to triple diagnostic procedure in palpable and non-palpable breast lesions

Purpose: The aim of this study was to determine the clinical value of scintimammography with 99m-Tc-MIBI ( Sc) as a complementary method to the triple diagnostic procedure in the diagnosis of breast lesions.

Material and Methods: Ninety-six consecutive patients with 65 palpable and 54 non-palpable breast lesions were included in a prospective study. All lesions were evaluated by clinical examination, mammography and fine-needle-aspiration cytology (FNAC), called triple diagnostic procedure ( TD). Prone planar scintimammography with 99m-Tc-MIBI was performed in all patients. Five groups were defined for diagnosis: 1 = normal; 2 = benign; 3 = probably benign; 4 = highly suspect of malignancy; and 5 = malignant. In the calculations, groups 1–3 were considered benign, and 4–5 malignant. All lesions were excised and examined histologically. The additional value of Sc +  TD procedure was studied separately for palpable and non-palpable lesions.

Results: Histologically, 83 malignant and 36 benign lesions were found in the 119 breast lesions. Sensitivity for malignancy in palpable lesions of TD alone and of the combination TD +  Sc were 95.6% and 100%, respectively. Sensitivity for malignancy in non-palpable lesions of TD and TD +  Sc was 89.1% and 97.2%, respectively.

Conclusion: Adding scintimammography to the triple diagnostic procedure increased the sensitivity for the detection of both palpable and non-palpable breast cancers, but decreased the specificity.

Reduced breast cancer mortality after 20+ years of follow-up in the Swedish randomized controlled mammography trials in Malmö, Stockholm, and Göteborg

Objective To analyze the age- and trial-specific effects of the breast cancer screening trials with mammography in Malmö, Stockholm, and Göteborg. Methods The original trial files were linked to the Swedish Cancer and Cause of Death Registers to obtain date of breast cancer diagnosis and date and cause of death. Relative risks and 95% confidence intervals were calculated using the evaluation model (only breast cancers diagnosed between date of randomization and date when the first screening round of the control group was completed were included in the analysis). Results Women aged 40-70 at randomization in the Malmö I and II, Stockholm, and Göteborg trials were followed-up for an average of 30, 22, 25, and 24 years, respectively. The overview of all trials resulted in a significant decrease of 15% in breast cancer mortality. The variation by consecutive 10-year age group at randomization was small-from 21% in the age group 40-49 to 11% in the age group 50-59. After adjustment for age, there was a significant reduction in breast cancer mortality in the Göteborg trial (26%), and a non-significant reduction in the Malmö I and II and Stockholm trials (12%, 15%, and 5.8%, respectively). Conclusions The overview showed a 15% significant relative reduction in breast cancer mortality due to invitation to mammography screening. Heterogeneity in age, trial time, attendance rates, and length of screening intervals may have contributed to the variation in effect between the trials.

Time trends in axilla management among early breast cancer patients: Persisting major variation in clinical practice across European centers

Background We examined time trends in axilla management among patients with early breast cancer in European clinical settings. Material and methods EUROCANPlatform partners, including population-based and cancer center-specific registries, provided routinely available clinical cancer registry data for a comparative study of axillary management trends among patients with first non-metastatic breast cancer who were not selected for neoadjuvant therapy during the last decade. We used an additional short questionnaire to compare clinical care patterns in 2014. Results Patients treated in cancer centers were younger than population-based registry populations. Tumor size and lymph node status distributions varied little between settings or over time. In 2003, sentinel lymph node biopsy (SLNB) use varied between 26% and 81% for pT1 tumors, and between 2% and 68% for pT2 tumors. By 2010, SLNB use increased to 79-96% and 49-92% for pT1 and pT2 tumors, respectively. Axillary lymph node dissection (ALND) use for pT1 tumors decreased from between 75% and 27% in 2003 to 47% and 12% in 2010, and from between 90% and 55% to 79% and 19% for pT2 tumors, respectively. In 2014, important differences in axillary management existed for patients with micrometastases only, and for patients fulfilling the ACOSOG Z0011 criteria for omitting ALND. Conclusion This study demonstrates persisting differences in important aspects of axillary management throughout the recent decade. The results highlight the need for international comparative patterns of care studies in oncology, which may help to identify areas where further studies and consensus building may be necessary.

Population-based analysis of colorectal cancer risk after oophorectomy

BACKGROUND

The development of colorectal cancer is influenced by hormonal factors. Oophorectomy alters endogenous levels of sex hormones, but the effect on colorectal cancer risk is unclear. The aim of this cohort study was to examine colorectal cancer risk after oophorectomy for benign indications.

METHODS

Women who had undergone oophorectomy between 1965 and 2011 were identified from the Swedish Patient Registry. Standard incidence ratios (SIRs) and 95 per cent confidence intervals for colorectal cancer risk were calculated compared with those in the general population. Stratification was carried out for unilateral and bilateral oophorectomy, and hysterectomy without specification of whether the ovaries were removed or not. Associations between the three oophorectomy options and colorectal cancer risk in different locations were assessed by means of hazard ratios (HRs) and 95 per cent confidence intervals calculated by Cox proportional hazards regression modelling.

RESULTS

Of 195 973 women who had undergone oophorectomy, 3150 (1·6 per cent) were diagnosed with colorectal cancer at a later date (median follow-up 18 years). Colorectal cancer risk was increased after oophorectomy compared with that in the general population (SIR 1·30, 95 per cent c.i. 1·26 to 1·35). The risk was lower for younger age at oophorectomy (15-39 years: SIR 1·10, 0·97 to 1·23; 40-49 years: SIR 1·26, 1·19 to 1·33; P for trend < 0·001). The risk was highest 1-4 years after oophorectomy (SIR 1·66, 1·51 to 1·81; P < 0·001). In the multivariable analysis, women who underwent bilateral oophorectomy had a higher risk of rectal cancer than those who had only unilateral oophorectomy (HR 2·28, 95 per cent c.i. 1·33 to 3·91).

CONCLUSION

Colorectal cancer risk is increased after oophorectomy for benign indications.

Abstract P3-11-14: Is pathologic complete response (pCR) a valid marker of outcome even in large breast cancer? Clinical results from a neoadjuvant trial using a combination of epirubicin, docetaxel and bevacizumab (PROMIX)

Background: Several randomized trials have proven that preoperative chemotherapy is equivalent to adjuvant treatment, and allows for clinical and radiological assessment of efficacy in vivo. Recent results show that response-guided neoadjuvant therapy is a favorable policy for hormone receptor positive tumors, while pCR predicts prognosis for triple-negative (TNBC) and HER2 positive breast cancer (von Minckwitz 2013; Cortazar 2014). Since 2012 the FDA accepts pCR (ypT0 ypN0) as endpoint for accelerated drug approval.

Methods: In total, 150 women 18 years or older with verified HER2 negative breast cancer suitable for primary medical treatment were included in the trial between September 2008 and December 2011. The patients received two courses of epirubicin and docetaxel (Taxotere®), both 75mg/m2 for the 1st two courses, followed by the same treatment with addition of bevacizumab (Avastin®) 15 mg/kg for 4 additional courses. Clinical and radiological evaluations with mammography and ultrasound were performed before start and after courses 2, 4 and 6. Core biopsies were taken before start, after 2 courses, and at time of surgery. Blood samples were drawn before and 24 hours after the first 4 courses.

Results: Median age was 49 years, range: 27 to 70 years; 73% were reported as ductal, 15% as lobular, and 12% as rare histological types. Mean tumor size was 59 mm, median 55 mm, range: 20-180 mm; 3 tumors (2.0%) were reported as inflammatory, and 13 (8.7%) presented with skin involvement (T4b). Enlarged axillary nodes were found in 102 patients (68%) before start of treatment, 77 of these (64%) verified as metastatic. SNB in cases of normal axillary status was performed in 16 cases, in 9 cases (8%) with positive finding. Supra- or infraclavicular node involvement was verified in 20 cases (13%). 25% of all tumors were ER- and/or PR-negative, tumor grade based on a diagnostic biopsy was evaluable in only 83 cases. Of these, 4 (5%) were grade I, 46 (55%) grade II, and 33 (40%) grade III. Mean proliferation count (Ki67) was 37%, median 30%, range 1-90%. Breakdown into intrinsic subtypes based on immunohistochemistry defined 68 (46%) as luminal A-like, 36 (24%) as luminal B-like, and 44 (30%) as TNBC. pCR was achieved in 20 cases, 3 (2%) luminal A-like, 5 (3.4%) luminal B-like and 12 (8.2%) TNBC. After 2.2 years of follow-up, 35 patients (23.3%) have experienced recurrence and 18 of these (12%) have deceased due to breast cancer, among these 6 despite pCR, 2 classified as luminal B-like, and 4 as TNBC. The molecular subtype of the tumor predicted outcome, but pCR was not in our material, even after adjustment for tumor size at diagnosis, a predictor of favorable outcome. The number of events in relation to molecular subtypes is however limited. Updated outcome data will be presented.

Conclusions: The present trial does not confirm previously reported observations that pCR is a marker of favorable prognosis. One possible explanation is that unfavorable biological characteristics, particularly heterogeneity, may increase with tumor burden. Genomic and proteomic analyses are currently ongoing.

Citation Format: Thomas Hatschek, Judith Bjöhle, Elisabet Lidbrink, Tobias Lekberg, Niklas Loman, Anna von Wachenfeldt Väppling, Martin Söderberg, Zakaria Einbeigi, Lena Carlsson, Henrik Lindman, Irma Fredriksson, Jan Frisell, Lars Löfgren, Lisa Rydén, Mats Hellström, Mårten Fernö, Jonas Bergh. Is pathologic complete response (pCR) a valid marker of outcome even in large breast cancer? Clinical results from a neoadjuvant trial using a combination of epirubicin, docetaxel and bevacizumab (PROMIX) [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-11-14.

Abstract P2-05-02: Preliminary translational results from PROMIX, a phase II trial of preoperative chemotherapy with the addition of bevacizumab in large operable and locally advanced HER2-negative breast cancer

Background: Preoperative chemotherapy in breast cancer (bc) provides unique possibilities to evaluate effects of therapy by studying response and changes in the tumor during the course of treatment. A pathologic complete response (pCR) correlates positively with long term prognosis in high-proliferating bc. In triple negative bc (TNBC) the prognosis was still relatively serious in cases with pCR in one large meta-analysis (Cortazar Lancet 2014).

Methods: 150 cases were included in this multicenter study, and treated with six cycles of epirubicin and docetaxel, adding bevacizumab from cycle 3, before surgery. Core needle biopsies were collected at free hand or with ultrasound (US) guidance and snap frozen at base-line and after cycle 2, tissue was also collected at surgery. Subtyping was performed using immunohistochemistry (IHC) of ER, Ki67 and HER2 according to modified St Gallen criteria; and using bead array gene expression profiling (GEX) according to PAM50.

Results: Biopsies were successfully retrieved from 145/150 pts at baseline, 138 after cycle 2 and 139 at surgery. The mRNA yield was adequate for GEX from 123/145 (85%) at baseline, 82/138 (59%) at cycle 2 and 71/139 (51%) at surgery, the decrease being a result of tumor shrinkage during treatment.

Initial PAM50 subtypes were as follows: luminal A (LA) 20%, luminal B (LB) 45%, HER2 5 %, basal like (BL) 22% and normal like (NL) 8%. PAM50 at baseline differed compared to IHC subtypes. Among IHC defined LA-like cases 15/33 (45%) were classified as LB by PAM50. Similarly, among IHC LB-like 22/57 (39%) were classified as non-LB (6 basal, 8 LA, 3 HER2 and 5 NL), while among IHC TNBC 7/28 (25%) were classified as non-BL subtypes (1 LA, 3 HER2 and 3 NL).

Of the pts with a baseline GEX analysis, 17 (14%) achieved a pCR. The observed pCR rates among PAM50 subtypes were: LA 8%, LB 5%, HER2 17%, BL 53% and NL 20%. For non-pCR cases, 39/52 (75%) of the tumors changed PAM50 subtype between baseline and surgery. The majority changed to the NL subtype. 33% of the LB tumors changed to the LA subtype.

Currently, after 2.2 years of follow-up, 16 pts are deceased due to bc. Among BL cases, 6/9 pts with a pCR at surgery remain alive; while 3/9 have died from bc. Exploratory analyses using functional gene modules (Desmedt Clin Cancer Res 2008) suggest that patients with BL tumors who have died have higher scores for PLAU/invasion and lower scores for STAT1/immune response compared with those who are still alive. Tumor size at baseline did not obviously correlate with outcome.

Conclusion: We show that biological material can be retrieved from a substantial fraction of cases treated within a multicenter study of preoperative chemotherapy. The success rate may be ameliorated by routine use of US guidance. The distribution of subtypes differs between modified IHC St Gallen criteria and PAM50, especially within the luminal subtypes. The pCR rate is highest among cases with a BL tumor at baseline. Shift of the gene signature between different subtypes during the course of treatment is frequent. In this set of relatively large tumors, the prognosis among BL bc appears to be adverse in spite of a pCR.

Citation Format: Niklas Loman, Ida Johansson, Judith Bjöhle, Jan Frisell, Tobias Lekberg, Lisa Rydén, Anna von Wachenfeldt, Jonas Bergh, Thomas Hatschek, Ingrid Hedenfalk. Preliminary translational results from PROMIX, a phase II trial of preoperative chemotherapy with the addition of bevacizumab in large operable and locally advanced HER2-negative breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P2-05-02.

Self-perceived, but not objective lymphoedema is associated with decreased long-term health-related quality of life after breast cancer surgery

BACKGROUND

The primary aim was to compare long-term health-related quality of life (HRQoL) in patients undergoing sentinel lymph node biopsy (SLNB) alone versus axillary lymph node dissection (ALND), with or without axillary metastases. Secondary aims were to a) investigate agreement between objectively measured and self-reported lymphoedema and b) compare, with respect to HRQoL, women with objective arm lymphoedema without subjective ratings and those with no objective but subjective ratings of arm lymphoedema.

METHODS

The three study groups were defined by axillary surgery: 1) SLNB alone (N = 140), 2) ALND in patients without axillary metastases (N = 125) and 3) ALND in patients with axillary metastases (N = 155). Preoperatively, one and three years postoperatively arm volume was measured and questionnaires regarding self-perceived symptoms of arm lymphoedema and HRQoL were completed (The Swedish Short Form-36 Health Survey, SF-36).

RESULTS

Out of the original 516 who had axillary surgery, 420 (81%) completed the study. There were no statistically significant differences in HRQoL between the three study groups. No statistically significant agreement was found between self-perceived and objectively measured arm lymphoedema. Women without self-perceived arm lymphoedema, regardless of objective arm lymphoedema or not, scored higher on all eight SF-36 domains than those who reported self-perceived arm lymphoedema.

CONCLUSION

Women reporting self-perceived arm lymphoedema, regardless of objective lymphoedema or not, have a decreased long-term health-related quality of life. This indicates that more attention should be given to the subjective reports of symptom in order to better help these women.

Arm lymphoedema after axillary surgery in women with invasive breast cancer

BACKGROUND

The primary aim was to compare arm lymphoedema after sentinel lymph node biopsy (SLNB) alone versus axillary lymph node dissection (ALND) in women with node-negative and node-positive breast cancer. The secondary aim was to examine the potential association between self-reported and objectively measured arm lymphoedema.

METHODS

Women who had surgery during 1999-2004 for invasive breast cancer in four centres in Sweden were included. The study groups were defined by the axillary procedure performed and the presence of axillary metastases: SLNB alone, ALND without axillary metastases, and ALND with axillary metastases. Before surgery, and 1, 2 and 3 years after operation, arm volume was measured and a questionnaire regarding symptoms of arm lymphoedema was completed. A mixed model was used to determine the adjusted mean difference in arm volume between the study groups, and generalized estimating equations were employed to determine differences in self-reported arm lymphoedema.

RESULTS

One hundred and forty women had SLNB alone, 125 had node-negative ALND and 155 node-positive ALND. Women who underwent SLNB had no increase in postoperative arm volume over time, whereas both ALND groups showed a significant increase. The risk of self-reported arm lymphoedema 1, 2 and 3 years after surgery was significantly lower in the SLNB group compared with that in both ALND groups. Three years after surgery there was a significant association between increased arm volume and self-reported symptoms of arm lymphoedema.

CONCLUSION

SLNB is associated with a minimal risk of increased arm volume and few symptoms of arm lymphoedema, significantly less than after ALND, regardless of lymph node status.

Abstract 4915: Estrogen receptor β is expressed within breast cancer cells with stem cell like capacity and confers endocrine sensitivity

Breast cancer stem-cells (BCSCs) are tumor-initiating cells expressing classical embryonal genes such as NANOG, SOX2 and NOTCH1, with a capacity to differentiate and form the heterogenous tumor mass in breast cancer. BCSCs are defined by their potential to grow as mammospheres in vitro together with their distinct cell-surface antigenic profile CD44+/CD24-/EpCAMlow as well as ALDH1-expression. It has been suggested that BCSCs are responsible for therapeutical resistance and metastasis.

About 70-80% of diagnosed breast cancers express ERα, which is demonstrated to have a central role in breast cancer progression and considered as a marker for endocrine sensitivity. However, in our research, BCSCs are confirmed to be ERα negative and supposed to be responding to estrogens only through paracrine signaling via stromal cells. We show that BCSCs purified from fresh surgically resected breast cancers express the second estrogen receptor; ERβ. It is also present in normal mammary stem cells (MSCs) isolated from breast reduction specimens. Surprisingly, stimulation of ERβ with a specific agonist expands the population of BCSCs but not MSCs . Knockdown of ERβ causes reduction in the number of mammospheres significantly along with decreased ALDH1 expression. We also find that treatment with tamoxifen is not sufficient to inhibit BCSCs proliferation although a specific ERβ antagonist reduces tumor growth in xenograft experiments as well as inhibits proliferation of primary cancer stem cells. In conclusion, we suggest endogenous ERβ is proliferative in cancer stem cells in vivo and in vitro, thus can be targeted by specific ligands, in turn opening up for a new direction in endocrine stem-cell specific therapy for breast cancer.

Citation Format: Ran Ma, Karthik Muralidharan Govindasamy, Gustaf Rosin, John Gustafsson, Anne Katchy, Linda Lindström, Camilla Hilliges, Lisa Viberg, Lennart Blomqvist, Jan Frisell, Cecilia Williams, Irma Fredriksson, Jonas Bergh, Johan Hartman. Estrogen receptor β is expressed within breast cancer cells with stem cell like capacity and confers endocrine sensitivity. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4915. doi:10.1158/1538-7445.AM2013-4915

Causes of false-negative sentinel node biopsy in patients with breast cancer

Background

Sentinel lymph node (SLN) biopsy has replaced axillary lymph node dissection as the routine staging procedure in clinically node-negative breast cancer. False-negative SLN biopsy results in misclassification and may cause undertreatment of the disease. The aim of this study was to investigate whether serial sectioning of SLNs reveals metastases more frequently in patients with false-negative SLNs than in patients with true-negative SLNs.

Methods

This was a case–control study. Tissue blocks from patients with false-negative SLNs, defined as tumour-positive lymph nodes excised at completion axillary dissection or a subsequent axillary tumour recurrence, were reassessed by serial sectioning and immunohistochemical staining. For each false-negative node, two true-negative SLN biopsies were analysed. Tumour and node characteristics in patients with false-negative SLNs were compared with those in patients with a positive SLN by univariable and multivariable regression analysis.

Results

Undiagnosed SLN metastases were discovered in nine (18 per cent) of 50 patients in the false-negative group and in 12 (11.2 per cent) of 107 patients in the true-negative group (P = 0.245). The metastases were represented by isolated tumour cells in 14 of these 21 patients. The risk of a false-negative SLN was higher in patients with hormone receptor-negative (odds ratio (OR) 2.50, 95 per cent confidence interval 1.17 to 5.33) or multifocal tumours (OR 3.39, 1.71 to 6.71), or if only one SLN was identified (OR 3.57, 1.98 to 6.45).

Conclusion

SLN serial sectioning contributes to a higher rate of detection of SLN metastasis. The rate of upstaging of the tumour is similar in false- and true-negative groups of patients.

High prevalence of human cytomegalovirus proteins and nucleic acids in primary breast cancer and metastatic sentinel lymph nodes

Background

Breast cancer is a leading cause of death among women worldwide. Increasing evidence implies that human cytomegalovirus (HCMV) infection is associated with several malignancies. We aimed to examine whether HCMV is present in breast cancer and sentinel lymph node (SLN) metastases.

Materials and Methods

Formalin-fixed paraffin-embedded tissue specimens from breast cancer and paired sentinel lymph node (SLN) samples were obtained from patients with (n = 35) and without SLN metastasis (n = 38). HCMV immediate early (IE) and late (LA) proteins were detected using a sensitive immunohistochemistry (IHC) technique and HCMV DNA by real-time PCR.

Results

HCMV IE and LA proteins were abundantly expressed in 100% of breast cancer specimens. In SLN specimens, 94% of samples with metastases (n = 34) were positive for HCMV IE and LA proteins, mostly confined to neoplastic cells while some inflammatory cells were HCMV positive in 60% of lymph nodes without metastases (n = 35). The presence of HCMV DNA was confirmed in 12/12 (100%) of breast cancer and 10/11 (91%) SLN specimens from the metastatic group, but was not detected in 5/5 HCMV-negative, SLN-negative specimens. There was no statistically significant association between HCMV infection grades and progesterone receptor, estrogen receptor alpha and Elston grade status.

Conclusions

The role of HCMV in the pathogenesis of breast cancer is unclear. As HCMV proteins were mainly confined to neoplastic cells in primary breast cancer and SLN samples, our observations raise the question whether HCMV contributes to the tumorigenesis of breast cancer and its metastases.

Abstract P3-07-03: The impact of Carcinoma in situ of the breast and family history on risk of subsequent breast cancer events and mortality - a population based study from Sweden

Purpose: To evaluate the long-term risk of subsequent breast cancer and mortality among women diagnosed with carcinoma in situ of the breast.

Patients and Methods: Using the population-based Swedish Multi-Generation and Cancer Registers we selected 8,111 women diagnosed with in situ breast cancer between 1980 and 2004. We estimated the relative risks of subsequent ipsi- and contralateral invasive breast cancer or a contalateral in situ expressed as standardized incidence ratios (SIRs), in relation to age, year, time since diagnosis and family history (1st degree relative) for breast cancer. The relative risk of death was expressed as standardized mortality ratio, (SMR).

Results: Of 8,111 women identified with first in situ, 859 had a family history for breast cancer. The overall risk of a subsequent invasive breast cancer is over four fold and the risk for contralateral in situ breasts cancer was almost seven fold, compared with the risk in healthy women.

Prediction of non-sentinel lymph node status in breast cancer patients with sentinel lymph node metastases: evaluation of the tenon score

INTRODUCTION

Current guidelines recommend completion axillary lymph node dissection (cALND) in case of a sentinel lymph node (SLN) metastasis larger than 0.2 mm. However, in 50%-65% of these patients, the non-SLNs contain no further metastases and cALND provides no benefit. Several nomograms and scoring systems have been suggested to predict the risk of metastases in non-SLNs. We have evaluated the Tenon score.

PATIENTS AND METHODS

In a retrospective review of the Swedish Sentinel Node Multicentre Cohort Study, risk factors for additional metastases were analysed in 869 SLN-positive patients who underwent cALND, using uni- and multivariate logistic regression models. A receiver operating characteristic (ROC) curve was drawn on the basis of the sensitivity and specificity of the Tenon score, and the area under the curve (AUC) was calculated.

RESULTS

Non-SLN metastases were identified in 270/869 (31.1%) patients. Tumour size and grade, SLN status and ratio between number of positive SLNs and total number of SLNs were significantly associated with non-SLN status in multivariate analyses. The area under the curve for the Tenon score was 0.65 (95% CI 0.61-0.69). In 102 patients with a primary tumour <2 cm, Elston grade 1-2 and SLN metastases ≤2 mm, the risk of non SLN metastasis was less than 10%.

CONCLUSION

The Tenon score performed inadequately in our material and we could, based on tumour and SLN characteristics, only define a very small group of patients in which negative non-sentinel nodes could be predicted.

Axillary recurrence rate 5 years after negative sentinel node biopsy for breast cancer

BACKGROUND

Sentinel lymph node (SLN) biopsy has replaced axillary lymph node dissection (ALND) as the standard axillary staging procedure in breast cancer. Follow-up studies in SLN-negative women treated without ALND report low rates of axillary recurrence, but most studies have short follow-up, and few are multicentre studies.

METHODS

Between September 2000 and January 2004, patients who were SLN-negative and did not have ALND were included in a prospective cohort. Kaplan-Meier estimates were used to analyse the rates of axillary recurrence and survival. The risk of axillary recurrence was also compared in centres with high and low experience with the SLN biopsy (SLNB) technique.

RESULTS

A total of 2195 patients with 2216 breast tumours were followed for a median of 65 months. Isolated axillary recurrence was diagnosed in 1·0 per cent of patients. The event-free 5-year survival rate was 88·8 per cent and the overall 5-year survival rate 93·1 per cent. There was no difference in recurrence rates between centres contributing fewer than 150 SLNB procedures to the cohort and centres contributing 150 or more procedures.

CONCLUSION

This study confirmed the low risk of axillary recurrence 5 years after SLNB for breast cancer without ALND.