Omission of Axillary Dissection Following Nodal Downstaging With Neoadjuvant Chemotherapy

Importance

Data on oncological outcomes after omission of axillary lymph node dissection (ALND) in patients with breast cancer that downstages from node positive to negative with neoadjuvant chemotherapy are sparse. Additionally, the best axillary surgical staging technique in this scenario is unknown.

Objective

To investigate oncological outcomes after sentinel lymph node biopsy (SLNB) with dual-tracer mapping or targeted axillary dissection (TAD), which combines SLNB with localization and retrieval of the clipped lymph node.

Design, Setting, and Participants

In this multicenter retrospective cohort study that was conducted at 25 centers in 11 countries, 1144 patients with consecutive stage II to III biopsy-proven node-positive breast cancer were included between April 2013 and December 2020. The cumulative incidence rates of axillary, locoregional, and any invasive (locoregional or distant) recurrence were determined by competing risk analysis.

Exposure

Omission of ALND after SLNB or TAD.

Main Outcomes and Measures

The primary end points were the 3-year and 5-year rates of any axillary recurrence. Secondary end points included locoregional recurrence, any invasive (locoregional and distant) recurrence, and the number of lymph nodes removed.

Results

A total of 1144 patients (median [IQR] age, 50 [41-59] years; 78 [6.8%] Asian, 105 [9.2%] Black, 102 [8.9%] Hispanic, and 816 [71.0%] White individuals; 666 SLNB [58.2%] and 478 TAD [41.8%]) were included. A total of 1060 patients (93%) had N1 disease, 619 (54%) had ERBB2 (formerly HER2)-positive illness, and 758 (66%) had a breast pathologic complete response. TAD patients were more likely to receive nodal radiation therapy (85% vs 78%; P = .01). The clipped node was successfully retrieved in 97% of TAD cases and 86% of SLNB cases (without localization). The mean (SD) number of sentinel lymph nodes retrieved was 3 (2) vs 4 (2) (P < .001), and the mean (SD) number of total lymph nodes removed was 3.95 (1.97) vs 4.44 (2.04) (P < .001) in the TAD and SLNB groups, respectively. The 5-year rates of any axillary, locoregional, and any invasive recurrence in the entire cohort were 1.0% (95% CI, 0.49%-2.0%), 2.7% (95% CI, 1.6%-4.1%), and 10% (95% CI, 8.3%-13%), respectively. The 3-year cumulative incidence of axillary recurrence did not differ between TAD and SLNB (0.5% vs 0.8%; P = .55).

Conclusions and Relevance

The results of this cohort study showed that axillary recurrence was rare in this setting and was not significantly lower after TAD vs SLNB. These results support omission of ALND in this population.

The American Society of Breast Surgeons classification system for oncoplastic breast conserving surgery independently predicts the risk of delayed wound healing

INTRODUCTION

Oncoplastic breast conserving surgery (OBCS) aims to provide safe and satisfying surgery for breast cancer patients. The American Society of Breast Surgeons (ASBrS) classification system is based on volumetric displacement cut-offs (level I for <20% of breast volume; level II for 20-50%). It aims to facilitate communication among treating physicians and patients. Here, we investigate whether the extent of OBCS as classified by ASBrS independently predicts postoperative complications.

MATERIALS AND METHODS

This retrospective analysis of a prospectively maintained database included patients with stage I-III breast cancer who underwent OBCS between 03/2011 and 12/2020 at a Swiss university hospital. Outcomes included short-term (≤30 days) complications and chronic (>30 days) pain after surgery. Multivariate logistic regression models were used to identify independent predictors.

RESULTS

In total, 439 patients were included, 314 (71.5%) received ASBrS level I surgery, and 125 (28.5%) underwent ASBrS level II surgery. ASBrS level II was found to be an independent predictor of delayed wound healing (odds ratio [OR] 9.75, 95% confidence intervals (CI) 2.96-32.10). However, ASBrS level did not predict chronic postoperative pain (incidence rate ratio [IRR] 1.20, 95%CI 0.85-1.70), as opposed to age (IRR 1.19, 95%CI 1.11-1.27 per 5 years decrease), and weight disorders (underweight [BMI <18.5] vs. normal weight [BMI 18.5 < 25]: IRR 4.02, 95%CI 1.70-9.54; obese [BMI ≥30] vs. normal weight: IRR 2.07, 95%CI 1.37-3.13).

CONCLUSION

ASBrS level II surgery predicted delayed wound healing, warranting close clinical follow-up and prompt treatment to avoid delays in adjuvant therapy.

Trends in use of neoadjuvant systemic therapy in patients with clinically node-positive breast cancer in Europe: prospective TAXIS study (OPBC-03, SAKK 23/16, IBCSG 57-18, ABCSG-53, GBG 101)

PURPOSE

The aim of this study was to evaluate clinical practice heterogeneity in use of neoadjuvant systemic therapy (NST) for patients with clinically node-positive breast cancer in Europe.

METHODS

The study was preplanned in the international multicenter phase-III OPBC-03/TAXIS trial (ClinicalTrials.gov Identifier: NCT03513614) to include the first 500 randomized patients with confirmed nodal disease at the time of surgery. The TAXIS study's pragmatic design allowed both the neoadjuvant and adjuvant setting according to the preferences of the local investigators who were encouraged to register eligible patients consecutively.

RESULTS

A total of 500 patients were included at 44 breast centers in six European countries from August 2018 to June 2022, 165 (33%) of whom underwent NST. Median age was 57 years (interquartile range [IQR], 48-69). Most patients were postmenopausal (68.4%) with grade 2 and 3 hormonal receptor-positive and human epidermal growth factor receptor 2-negative breast cancer with a median tumor size of 28 mm (IQR 20-40). The use of NST varied significantly across the countries (p < 0.001). Austria (55.2%) and Switzerland (35.8%) had the highest percentage of patients undergoing NST and Hungary (18.2%) the lowest. The administration of NST increased significantly over the years (OR 1.42; p < 0.001) and more than doubled from 20 to 46.7% between 2018 and 2022.

CONCLUSION

Substantial heterogeneity in the use of NST with HR+/HER2-breast cancer exists in Europe. While stringent guidelines are available for its use in triple-negative and HER2+ breast cancer, there is a need for the development of and adherence to well-defined recommendations for HR+/HER2-breast cancer.

Use of sentinel lymph node biopsy in elderly patients with breast cancer - 10-year experience from a Swiss university hospital

BACKGROUND

The Choosing Wisely initiative recommended the omission of routine sentinel lymph node biopsy (SLNB) in patients ≥ 70 years of age, with clinically node-negative, early stage, hormone receptor (HR) positive and human epidermal growth factor receptor 2 (Her2) negative breast cancer in August 2016. Here, we assess the adherence to this recommendation in a Swiss university hospital.

METHODS

We conducted a retrospective single center cohort study from a prospectively maintained database. Patients ≥ 18 years of age with node-negative breast cancer were treated between 05/2011 and 03/2022. The primary outcome was the percentage of patients in the Choosing Wisely target group who underwent SLNB before and after the initiative went live. Statistical significance was tested using chi-squared test for categorical and Wilcoxon rank-sum tests for continuous variables.

RESULTS

In total, 586 patients met the inclusion criteria with a median follow-up of 2.7 years. Of these, 163 were ≥ 70 years of age and 79 were eligible for treatment according to the Choosing Wisely recommendations. There was a trend toward a higher rate of SLNB (92.7% vs. 75.0%, p = 0.07) after the Choosing Wisely recommendations were published. In patients ≥ 70 years with invasive disease, fewer received adjuvant radiotherapy after omission of SLNB (6.2% vs. 64.0%, p < 0.001), without differences concerning adjuvant systemic therapy. Both short-term and long-term complication rates after SLNB were low, without differences between elderly patients and those < 70 years.

CONCLUSIONS

Choosing Wisely recommendations did not result in a decreased use of SLNB in the elderly at a Swiss university hospital.

Uncertainties and controversies in axillary management of patients with breast cancer

The aims of this Oncoplastic Breast Consortium and European Breast Cancer Research Association of Surgical Trialists initiative were to identify uncertainties and controversies in axillary management of early breast cancer and to recommend appropriate strategies to address them. By use of Delphi methods, 15 questions were prioritized by more than 250 breast surgeons, patient advocates and radiation oncologists from 60 countries. Subsequently, a global virtual consensus panel considered available data, ongoing studies and resource utilization. It agreed that research should no longer be prioritized for standardization of axillary imaging, de-escalation of axillary surgery in node-positive cancer and risk evaluation of modern surgery and radiotherapy. Instead, expert consensus recommendations for clinical practice should be based on current evidence and updated once results from ongoing studies become available. Research on de-escalation of radiotherapy and identification of the most relevant endpoints in axillary management should encompass a meta-analysis to identify knowledge gaps, followed by a Delphi process to prioritize and a consensus conference to refine recommendations for specific trial designs. Finally, treatment of residual nodal disease after surgery was recommended to be assessed in a prospective register.

Abstract P2-14-08: Trends in neoadjuvant systemic therapy rates in Europe: Pre-planned substudy of TAXIS (OPBC-03, SAKK 23/16, IBCSG 57-18, ABCSG-53, GBG 101)

Introduction: Even though randomized controlled trials could not show a significant survival benefit for the use of neoadjuvant systemic therapy (NST), it is increasingly recommended for patients with clinically node-positive breast cancer due to its implications on prognosis, locoregional downstaging and response-driven adjuvant systemic therapy. The aim of this study was to assess the need for international standardization of treatment recommendations by evaluating clinical practice heterogeneity in use of NST for patients with clinically node-positive breast cancer in Europe. Methods: The study was preplanned in the international multicenter phase-III OPBC-03/TAXIS trial (ClinicalTrials.gov Identifier: NCT03513614) after randomization of the first 500 patients with clinically node-positive breast cancer who underwent axillary lymph node dissection (ALND) or axillary radiation (ART) without ALND after tailored axillary surgery (TAS) in the context of extended regional nodal irradiation. Clinically node-positive breast cancer was defined by confirmed nodal disease at the time of initial diagnosis; in case of neoadjuvant therapy, residual nodal disease was mandatory. Investigators were encouraged to enroll all eligible patients consecutively. However, TAXIS is unique inasmuch as its pragmatic design allows both the neoadjuvant and adjuvant setting according to the preferences of the treating physicians and institutions and thus provides an excellent opportunity to study patterns and trends in use of NST in patients with clinically positive nodes in Europe. Results: A total of 500 patients with a median age of 57 years (IQR: 48-69 years) were included at 44 breast centers in 6 European countries from August 2018 to June 2022. Subtype was hormone receptor (HR) positive (+) and human epidermal growth factor receptor 2 (HER2) negative (-) in 393 (80.0%), HR+/HER2+ in 52 (10.6%), HR-/HER2+ in 5 (1.0%) and HR-/HER2- in 34 (6.9%) patients. The rate of patients undergoing NST was 31.4% with a significant upward trend over time during the study period (from 20.0% in 2018 to 38.1% in 2022; p=0.044). The use of NST varied significantly by country (p=&lt; 0.001) and by site (p=0.015). For patients with clinical AJCC tumor stage II and III, the rates of patients undergoing NST in Switzerland were 26.5% (18 of 68) and 35.9% (92 of 256), in Germany 22.2% (2 of 9) and 30.4% (7 of 23), in Austria 50% (7 of 14) and 60% (9 of 15) and in Hungary 0% (0 of 15) and 20.7% (18 of 87), respectively (p=0.019 and 0.004). Large differences by country were found for ER+/HER2- breast cancer, ranging from 13.1% (11 of 84) in Hungary to 47.8% (11 of 23) in Austria (p=0.007). Within Switzerland, which was the country with most included patients (328 of 500) and participating sites (n=25), the rate of patients undergoing NST for ER+/HER2- breast cancer varied considerably by site, ranging from 10% (2 of 20) to 50% (11 of 22). Discussion: This study revealed substantial heterogeneity in clinical practice in Europe, indicating the need for development of and adherence to consistent guidelines to standardize the international use of NST.

Citation Format: Walter P. Weber, Zoltan Matrai, Stefanie Hayoz, Guido Henke, Daniel R. Zwahlen, Günther Gruber, Frank Zimmermann, Thomas Ruhstaller, Simone Muenst, Markus Ackerknecht, Christian Kurzeder, Sherko Küemmel, Vesna Bjelic-Radisic, Viktor Smanykó, Conny Vrieling, Rok Satler, Inna Meyer, Charles Becciolini, Susanne Bucher, Colin Simonson, Peter M. Fehr, Natalie Gabriel, Robert Maráz, Dimitri Sarlos, Konstantin J. Dedes, Cornelia Leo, Gilles Berclaz, Hisham Fansa, Christopher Hager, Klaus Reisenberger, Ákos Sávolt, Christian F. Singer, Roland Reitsamer, Jelena Winkler, Giang Thanh Lam Lam, Mathias K. Fehr, Tatiana Naydina, Magdalena Kohlik, Karine Clerc, Valerijus Ostapenko, Florian Fitzal, Martin Heidinger, Nadia Maggi, Alexandra Schulz, Pagona Markellou, Loïc Lelièvre, Daniel Egle, Jörg Heil, Michael Knauer, Christoph Tausch. Trends in neoadjuvant systemic therapy rates in Europe: Pre-planned substudy of TAXIS (OPBC-03, SAKK 23/16, IBCSG 57-18, ABCSG-53, GBG 101) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-14-08.

Abstract GS4-02: Oncological Outcomes Following Omission of Axillary Lymph Node Dissection in Node Positive Patients Downstaging To Node Negative with Neoadjuvant Chemotherapy: the OPBC-04/EUBREAST-06/OMA study

Background: Data on the oncologic safety of omission of axillary lymph node dissection (ALND) in node positive (N+) patients who downstage to ypN0 with neoadjuvant chemotherapy (NAC) is sparse. Additionally, there is no consensus on which axillary staging procedure should be used in this setting, sentinel lymph node biopsy (SLNB) alone or in combination with localization and retrieval of the clipped positive node, also known as targeted axillary dissection (TAD). Whether the reduction in the false negative rate observed with TAD translates into a significant reduction in the rate of axillary recurrence is unknown. We sought to evaluate oncologic outcomes after omission of ALND in a large, real-world cohort of breast cancer (BC) patients and to compare rates of axillary recurrence after SLNB with dual tracer mapping vs. TAD.

Methods: Data were collected from 19 centers in the Oncoplastic Breast Consortium (OPBC) and EUBREAST networks. Patients with T1-4 biopsy-proven N1-3 BC who underwent NAC followed by axillary staging with either SLNB with dual tracer mapping or TAD and who were pathologically node negative (ypN0) were included. ypN0 was defined as the absence of any tumor or isolated tumor cells. Competing risk analysis was performed to assess the cumulative incidence rates of axillary recurrence, locoregional recurrence, and any invasive (locoregional or distant) recurrence. Two-year cumulative incidence rates were compared between TAD and SLNB using the Gray’s test. Type I error rate was set to 0.05 (α).

Results: We included 785 patients (565 treated with SLNB and 220 with TAD) treated with NAC followed by surgery from 01/2014-12/2020. Median patient age was 50 years. The majority (57%) of patients had clinical T2 tumors, and 95% had N1 disease. Most (55%) were HER2+, and 21% were triple negative. Most patients (81%) received anthracycline and taxane-based chemotherapy regimens, but NAC regimens differed between patients treated with TAD and those treated with SLNB (Table 1). All patients with HER2+ tumors received anti HER2 therapy. Nodal radiotherapy was administered to 76% of patients, and was more common in patients who underwent TAD (82% TAD vs 74% SLNB, p=0.017). Breast pathologic complete response (ypT0/is) was more frequent among those patients that had TAD (80% TAD vs. 66% SLNB, p&lt; 0.001). TAD localization was with wire in 46%, radioactive seed in 40%, ultrasound in 5%, tattoo in 2%, and with a combination of these techniques in 7%. The clipped node was successfully retrieved in 94% of TAD cases. The median number of lymph nodes removed was lower in the TAD group compared to the SLNB group [3 (IQR 3-5) vs 4 IQR 3-5), p&lt; 0.001], as was the median number of sentinel lymph nodes [3 (IQR 2-4) vs 4 IQR 3-5), p&lt; 0.001] (Table 1). The 5-year rates of any axillary recurrence, locoregional recurrence, and any invasive recurrence in the entire cohort were 1.1% (95%CI 0.39-2.4%), 3.1% (95%CI 1.6-5.3%) and 10% (95%CI 7.6-13%), respectively. The two-year cumulative incidence of axillary recurrence did not differ between patients treated with TAD compared to SLNB (0% vs 0.9%, p=0.19).

Conclusion: Early axillary recurrence after omission of ALND in patients who successfully downstage from N+ to ypN0 with NAC is a rare event following both SLNB or TAD, and was not significantly lower in TAD than SLNB. Although longer follow-up is needed to confirm these findings, the main advantage of TAD seems to be a reduction in the number of lymph nodes removed. Overall, these results support omission of ALND in patients who successfully downstage to node negative disease after NAC.

Table 1: Clinicopathological Features of the Study Cohort, Stratified by Axillary Staging Technique

Citation Format: Giacomo Montagna, Mary Mrdutt, Astrid Botty, Andrea V. Barrio, Varadan Sevilimedu, Judy C. Boughey, Tanya L. Hoskin, Laura H. Rosenberger, E Shelley Hwang, Abigail Ingham, Bärbel Papassotiropoulos, Bich Doan Nguyen-Sträuli, Christian Kurzeder, Danilo Diaz Aybar, Denise Vorburger, Dieter Michael Matlac, Edvin Ostapenko, Fabian Riedel, Florian Fitzal, Francesco Meani, Franziska Fick, Jacqueline Sagasser, Jörg Heil, Konstantin J. Dedes, Laszlo Romics, Maggie Banys-Paluchowski, Maria Del Rosario Cueva Perez, Marcelo Chavez Diaz, Martin Heidinger, Mathias K. Fehr, Mattea Reinisch, Nadia Maggi, Nicola Rocco, Nina Ditsch, Oreste Davide Gentilini, Regis Resende Paulinelli, Sebastian Sole Zarhi, Sherko Küemmel, Simona Bruzas, Simona Di Lascio, Tamara Parissenti, Uwe Güth, Valentina Ovalle, Christoph Tausch, Monica Morrow, Thorsten Kühn, Walter P. Weber. Oncological Outcomes Following Omission of Axillary Lymph Node Dissection in Node Positive Patients Downstaging To Node Negative with Neoadjuvant Chemotherapy: the OPBC-04/EUBREAST-06/OMA study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS4-02.

The impact of neoadjuvant systemic treatment on postoperative complications in breast cancer surgery

PURPOSE

The aim of the study was to analyze the impact of neoadjuvant systemic treatment (NST) on postoperative complications and the beginning of adjuvant treatment.

METHODS

This study includes data from a prospectively maintained database including patients with breast cancer (BC) stage I-IV with or without NST undergoing breast cancer surgery between January 2010 and September 2021.

RESULTS

Out of 517 enrolled patients, 77 received NST, 440 had primary breast surgery. After NST patients underwent surgery after a meantime of 34 days (26.5-40 days). No statistical significance could be found comparing the complication grading according to the Clavien Dindo classification. The complications were most frequently rated as grade 3b. There were no complications with grade 4 or higher. When differentiating into short and long-term, the overall rate of short-term complications was 20.3% with no significant difference between the two groups (20.8% vs. 20.2%). Regarding long-term complications, there was more impairment of shoulder mobility (26.0% vs. 9.5%, p ≤ 0.001) and chronic pain (42.9% vs. 28.6%, p ≤ 0.016) for patients with NST. The beginning of the administration of the adjuvant treatment was comparable in both groups (46.3 days vs. 50.5 days).

CONCLUSION

In our cohort, complications between both groups were comparable according to Clavien Dindo. This study shows that NST has no negative impact on postoperative short-term complications and most importantly did not lead to a delay of the beginning of adjuvant treatment. Therefore, NST can be safely admitted, even when followed by extensive breast reconstruction surgery.

Exposure to escalating olaparib does not induce acquired resistance to PARPi and to other chemotherapeutic compounds in ovarian cancer cell lines

Poly (ADP-ribose) polymerase (PARP)-inhibitors (PARPi) such as olaparib and niraparib are currently used as a treatment option for BRCA-deficient tumors and also show efficacy in platinum-sensitive tumors. However, resistance to PARPi occurs in numerous patients and in particular acquired PARPi resistance presents a major obstacle in the treatment of these tumors. In the present study, it was investigated whether stepwise exposure of ovarian cancer cells to escalating concentrations of olaparib produced subcells with acquired resistance to PARPi and/or acquired cross-resistance to platinum compounds, paclitaxel, and doxorubicin. To this aim, the sensitivity of fourteen ovarian cancer cell lines, including nine with TP53-mutations and five carrying BRCA-mutations, to olaparib and niraparib was determined and a subset of seven cell lines was selected to investigate the potential of olaparib to produce resistance. It was identified that escalating olaparib did neither produce subcells with acquired PARPi-resistance nor did it produce acquired cross-resistance to platinum compounds, doxorubicin, and paclitaxel. This finding was independent of the cells' TP53 and BRCA mutation status. CRISPR-Cas9 mediated deletion of PARP1 did not affect sensitivity to PARPi, platinum compounds, doxorubicin, and paclitaxel. In addition, olaparib sensitivity correlated with niraparib sensitivity, but BRCA-mutated cells were not more sensitive to PARPi. Moreover, PARPi sensitivity associated with cross-sensitivity not only to platinum compounds but also to anthracylines, paclitaxel, and inhibitors of histone deacetylases. These in vitro data indicated that olaparib exposure is unlikely to produce an acquired resistance phenotype and that PARPi-sensitive ovarian cancer cells are also cross-sensitive to non-platinum and even to compounds not directly interacting with the DNA.

Oncoplastic breast consortium recommendations for mastectomy and whole breast reconstruction in the setting of post-mastectomy radiation therapy

Aim

Demand for nipple- and skin- sparing mastectomy (NSM/SSM) with immediate breast reconstruction (BR) has increased at the same time as indications for post-mastectomy radiation therapy (PMRT) have broadened. The aim of the Oncoplastic Breast Consortium initiative was to address relevant questions arising with this clinically challenging scenario.

Methods

A large global panel of oncologic, oncoplastic and reconstructive breast surgeons, patient advocates and radiation oncologists developed recommendations for clinical practice in an iterative process based on the principles of Delphi methodology.

Results

The panel agreed that surgical technique for NSM/SSM should not be formally modified when PMRT is planned with preference for autologous over implant-based BR due to lower risk of long-term complications and support for immediate and delayed-immediate reconstructive approaches. Nevertheless, it was strongly believed that PMRT is not an absolute contraindication for implant-based or other types of BR, but no specific recommendations regarding implant positioning, use of mesh or timing were made due to absence of high-quality evidence. The panel endorsed use of patient-reported outcomes in clinical practice. It was acknowledged that the shape and size of reconstructed breasts can hinder radiotherapy planning and attention to details of PMRT techniques is important in determining aesthetic outcomes after immediate BR.

Conclusions

The panel endorsed the need for prospective, ideally randomised phase III studies and for surgical and radiation oncology teams to work together for determination of optimal sequencing and techniques for PMRT for each patient in the context of BR

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Autologous breast reconstruction is increasingly preferred over implants in the setting of radiation therapy.

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Use of patient-reported outcomes is endorsed.

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Shape and size of reconstructed breasts can hinder radiotherapy planning.

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There is a need for randomised phase III trials.

Tailored axillary surgery in patients with clinically node-positive breast cancer: Pre-planned feasibility substudy of TAXIS (OPBC-03, SAKK 23/16, IBCSG 57-18, ABCSG-53, GBG 101)

Aim

We developed tailored axillary surgery (TAS) to reduce the axillary tumor volume in patients with clinically node-positive breast cancer to the point where radiotherapy can control it. The aim of this study was to quantify the extent of tumor load reduction achieved by TAS.

Methods

International multicenter prospective study embedded in a randomized trial. TAS is a novel pragmatic concept for axillary surgery de-escalation that combines palpation-guided removal of suspicious nodes with the sentinel procedure and, optionally, imaging-guided localization. Pre-specified study endpoints quantified surgical extent and reduction of tumor load.

Results

A total of 296 patients were included at 28 sites in four European countries, 125 (42.2%) of whom underwent neoadjuvant chemotherapy (NACT) and 71 (24.0%) achieved nodal pathologic complete response. Axillary metastases were detectable only by imaging in 145 (49.0%) patients. They were palpable in 151 (51.0%) patients, of whom 63 underwent NACT and 21 had residual palpable disease after NACT. TAS removed the biopsied and clipped node in 279 (94.3%) patients. In 225 patients with nodal disease at the time of surgery, TAS removed a median of five (IQR 3–7) nodes, two (IQR 1–4) of which were positive. Of these 225 patients, 100 underwent ALND after TAS, which removed a median of 14 (IQR 10–17) additional nodes and revealed additional positive nodes in 70/100 (70%) of patients. False-negative rate of TAS in patients who underwent subsequent ALND was 2.6%.

Conclusions

TAS selectively reduced the tumor load in the axilla and remained much less radical than ALND.

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Tailored axillary surgery is a novel concept for clinically node-positive breast cancer

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Tailored axillary surgery selectively removes positive lymph nodes

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Tailored axillary surgery is much less radical than axillary dissection

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Tailored axillary surgery removes the clipped node in the vast majority of patients

Axillary surgery in node-positive breast cancer

Long-term follow-up data from multicenter phase III non-inferiority trials confirmed the safety of omission of axillary dissection in selected patients with clinically node-negative, sentinel node-positive breast cancer. Several ongoing trials investigate extended eligibility of the Z0011 protocol in the adjuvant setting. De-escalation of axillary surgery in patients with clinically node-positive breast cancer is currently limited to the neoadjuvant setting, where the sentinel procedure is used to determine nodal pathological complete response. Targeted axillary dissection lowers the false-negative rate of the sentinel procedure, which, however, is consistently associated with a very low risk of axillary recurrence in several recent single-center series. Axillary dissection remains standard care in patients with residual disease after neoadjuvant chemotherapy while the results of Alliance A011202 are pending. The TAXIS trial investigates the role of tailored axillary surgery in patients with clinically node-positive breast cancer, a novel concept designed to selectively remove positive nodes in the adjuvant and neoadjuvant setting.

Abstract PS1-64: Prepectoral implant-based breast reconstruction with TiLOOP-bra pocket - a single-center retrospective study

Aim: To evaluate the perioperative outcome and cosmetic outcome of prepectoral implant-based breast reconstruction using the TiLOOP® Bra Pocket.Background: Besides acellular dermal matrix (ADM), synthetic meshes have revealed good surgical and aesthetic outcomes. We present our data using TiLOOP® Bra Pocket, a ready-to-use mesh pocket which is made out of nonresorbable, titanized, lightweight polypropylene with a monofilament structure and designed to ensure optimal fixation of the breast implant following mastectomy. The idea behind the mesh pocket is to fix the implant to the muscle and provide coverage and stabilization for the implant by serving as an ´internal bra´, which will create an inferior and lateral sling to support the position and stability of the implant and prevent it from dislocating or twisting.

Materials and Methods: A single-center retrospective study was performed to assess short-term complication rates and cosmetic outcomes in patients with immediate or delayed implant-based breast reconstruction using the TiLOOP® Bra Pocket after nipple- or skin-sparing mastectomy. The primary endpoint was complication rates, which were divided into major and minor complications during the first 6 months. Minor complications were defined as those treated conservatively, major complications were those requiring surgical therapy. The secondary endpoint was short-term cosmetic outcome after 6 to 12 months, which was judged by two professionals using the Harvard score (1 = poor, 2 = fair, 3 = good, 4 = excellent).

Results: A total of 63 breasts (43 patients) were reconstructed by implant using the TiLOOP® Bra Pocket between 2018 and 2020, of which 57 were immediate reconstructions. Mean follow-up was 12 months. The overall complication rate was 30,2 % (n = 19/63). Major complications occured in 7 breasts (n = 7/63; 11,1 %) and minor complications occured in 12 breasts (12/63; 19,0 %). The cosmetic outcome was good (Harvard score: mean 3, range 1-4; SD 0,75). Seventeen cosmetic complications were observed (17/63; 27,0 %) and 6 cosmetic revision surgeries were performed (6/63; 9,5 %).

Conclusion: Immediate prepectoral implant-based breast reconstruction with the TiLOOP® Bra Pocket seems to be a feasible method with moderate complication rates and good cosmetic outcomes. Careful patient selection and preparation techniques considering flap viability are vital in order to achieve acceptable complication rates and satisfying cosmetic results. Long-term follow-up is needed. The next follow-up will be performed after 24 months.

Perioperative OutcomeComplications22Seroma with punction7/63 (11,1%)Seroma without punction1/63 (1,6 %)Hemorrhage2/63 (3,2 %)Nipple necrosis2/63 (3,2 %)Implant Infection3/63 (4,8 %)Skin Infection3/63 (4,8 %)Wound healing deficiency2/63 (3,2 %)Implant loss2/63 (3,2 %)Unplanned resurgery &lt; 3 mo8 (12,7 %)

Cosmetic Complication (N=17)Rippling2 (3,2 %)Asymmetry4 (6,3 %)Capsule contracture3 (4,8 %)Fat defects3 (4,8 %)Rotation2 (3,2 %)Cranialisation3 (4,8 %)

Cosmetic Outcome (Harvard score; 1 = poor, 2 = fair, 3 = good, 4 = excellent)Observer 13,0 (1 - 4), SD 0,8Observer 23,4 (1-4), SD 0,7

Citation Format: Bich Doan Nguyen, Denise Vorburger, Heike Frauchiger-Heuer, Lilian Bringolf, Nadia Maggi, Julia Talimi-Schnabel, Konstantin Dedes. Prepectoral implant-based breast reconstruction with TiLOOP-bra pocket - a single-center retrospective study [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS1-64.

Rapamycin reduces proteinuria and renal damage in the rat remnant kidney model

Rapamycin is an immunosuppressive drug used to prevent acute allograft rejection in solid organ transplantation. It shows less nephrotoxicity than calcineurin inhibitors. We evaluated the effect of rapamycin in rats undergoing 5/6 nephrectomy, a model of proteinuric and progressive renal failure. Fourteen days after surgery rats were randomized either to receive rapamycin or to remain untreated (control). Rats were humanely killed on day 91; serum creatinine, creatinine clearance, and proteinuria were assessed. Renal sections were stained with periodic acid-Schiff to evaluate glomerular volume (Gv), glomerulosclerosis (GS) and tubulointerstitial damage (TIS); we evaluated GS and TIS by Sirius red staining (SR). Epithelial-to-mesenchymal transition (EMT) was assessed by immunohistochemistry. Rapamycin affected neither serum creatinine nor creatinine clearance; it reduced Gv (controls, 5.9 +/- 3.1 x 10(6); rapamycin, 1.3 +/- 0.7 x 10(6) microm(3)) and proteinuria (control, 349 +/- 146; rapamycin, 56 +/- 27 mg/24 h; P < .05); rapamycin ameliorated GS (control, 78 +/- 7; rapamycin, 36 +/- 7%; P < .05; SR: control, 13.2 +/- 3.5; rapamycin, 3.8 +/- 1.0%; P < .05), and TIS (control, 3.25 +/- 0.5; rapamycin, 1.0 +/- 0.1; P < .05; SR: control, 29 +/- 3; rapamycin, 11 +/- 3%; P < .05). Rapamycin reduced alphaSMA (control, 3.25 +/- 0.5; rapamycin, 1.0 +/- 0.1; P < .05), VIM (control, 3.5 +/- 0.6; rapamycin, 1.0 +/- 1.4; P < .05), and CD68(+) cells infiltration (control, 110 +/- 43; rapamycin, 24 +/- 1 cells; P < .05). Rapamycin slows the progression of renal damage in the rat remnant kidney and may represent a novel approach to the treatment of chronic kidney disease.

Effects of sirolimus on human mesangial cells

Mesangial cell (MC) proliferation and production of extracellular matrix or loss of MC are both central findings in a number of renal proteinuric diseases. However, the role of MC as components of the glomerular filtration barrier and whether MC alterations induce changes in the glomerular filtration barrier leading to proteinuria are still matters of debate. The effects of Sirolimus (SRL) in proteinuric nephropathies is controversial: some papers have indicated a reduction and others, an increase in proteinuria after sirolimus treatment. Considering the pivotal role of MC in the pathogenesis of many chronic nephropathies, we evaluated the effect of SRL on cultured human MC. We treated primary human MC cultures with SRL, or platelet-derived growth factor (PDGF) or SRL + PDGF, or dimethylsulfoxide, the SRL vehicle, as a control. PDGF was used to activate MC. After 48 hours treatment, MC showed a significant growth increase that was significantly reduced by SRL (P < .01). Apoptosis, determined by the TUNEL assay and flow cytometry, was not modified by the treatments at 24 hours. SRL treatment increased significantly the number of alpha-smooth muscle actin-positive cells compared with controls (P < .05). Cells treated with SRL and SRL + PDGF showed significant changes in morphology with increased mean cell surface, perimeter, and maximum diameter (P < .01) but not protein content. Furthermore, MC treated with SRL showed decreased migration through polycarbonate membranes. The changes induced by SRL may help to explain some of the in vivo effects observed in SRL-treated patients.

Increased asymmetric dimethylarginine serum levels are associated with acute rejection in kidney transplant recipients

Asymmetric dimethylarginine (ADMA) has been identified as a marker of endothelial dysfunction and an independent risk factor for cardiovascular events in uremic subjects. This study evaluated ADMA plasma levels in kidney transplant recipients. ADMA levels were serially measured during the first year posttransplantation in 41 recipients treated with cyclosporine regimen (CY), sirolimus (SIR), or low-dose cyclosporine plus everolimus (E). Homocysteine, C reactive protein (CRP), nitric oxide (NO), and standard routine laboratory analyses were determined serially. ADMA significantly increased at 6 months posttransplantation, but was significantly lower among patients on SIR or E. NO was only slightly reduced in patients with increased ADMA levels. Interestingly, ADMA was significantly increased during the first 4 days posttransplantation in patients who experienced acute rejection during the first 6 months after transplantation. The same group of patients demonstrated higher levels of CRP and systolic blood pressure before transplantation. Our results demonstrated that ADMA was increased in patients on CY at 6 months. When increased soon after transplantation ADMA may be associated with episodes of acute rejection in kidney transplant recipients. The presence of elevated systolic blood pressure, as well as CRP and ADMA levels, suggested a role for endothelial dysfunction in the development of acute rejection episodes among deceased donor kidney transplant recipients.