St Gallen 2019 guidelines understage the axilla in lobular breast cancer: a population-based study.

BACKGROUND: The St Gallen 2019 guidelines for primary therapy of early breast cancer recommend omission of completion axillary lymph node dissection (cALND), regardless of histological type, in patients with one or two sentinel lymph node (SLN) metastases. Concurrently, adjuvant chemotherapy is endorsed for luminal A-like disease with four or more axillary lymph node (ALN) metastases. The aim of this study was to estimate the proportion of patients with invasive lobular cancer (ILC) versus invasive ductal cancer of no special type (NST) with one or two SLN metastases for whom cALND would have led to a recommendation for adjuvant chemotherapy. METHODS: Patients with ILC and NST who had surgery between 2014 and 2017 were identified in the National Breast Cancer Register of Sweden. After exclusion of patients with incongruent or missing data, those who fulfilled the St Gallen 2019 criteria for cALND omission were included in the population-based study cohort. RESULTS: Some 1886 patients in total were included in the study, 329 with ILC and 1507 with NST. Patients with ILC had a higher metastatic nodal burden and were more likely to have a luminal A-like subtype than those with NST. The prevalence of at least four ALN metastases was higher in ILC (31.0 per cent) than NST (14.9 per cent), corresponding to an adjusted odds ratio of 2.26 (95 per cent c.i. 1.59 to 3.21). Luminal A-like breast cancers with four or more ALN metastases were over-represented in ILC compared with NST, 52 of 281 (18.5 per cent) versus 43 of 1299 (3.3 per cent) (P < 0.001). CONCLUSION: Patients with ILC more often have luminal A-like breast cancer with at least four nodal metastases. Omission of cALND in patients with luminal A-like invasive lobular cancer and one or two SLN metastases warrants future attention as there is a risk of nodal understaging and undertreatment in one-fifth of patients.

Nowadays patients who have breast cancer with one to two metastases in the first draining axillary lymph nodes are not recommended to undergo completion surgery of the axilla if they have breast-conserving surgery and will have adequate postoperative oncological treatment. Lobular breast cancer is the second most common type of breast cancer, and this study shows that patients with this type have an increased risk of having lymph node metastases remaining if completion surgery is omitted. The diagnosis of additional lymph node metastases is importance for guidance regarding adjuvant oncological therapy in lobular cancer with a hormonally sensitive low proliferative subtype.

Validation of the Skåne University Hospital nomogram for the preoperative prediction of a disease-free axilla in patients with breast cancer.

BACKGROUND: Axillary staging via sentinel lymph node biopsy (SLNB) is performed for clinically node-negative (N0) breast cancer patients. The Skåne University Hospital (SUS) nomogram was developed to assess the possibility of omitting SLNB for patients with a low risk of nodal metastasis. Area under the receiver operating characteristic curve (AUC) was 0.74. The aim was to validate the SUS nomogram using only routinely collected data from the Swedish National Quality Registry for Breast Cancer at two breast cancer centres during different time periods. METHOD: This retrospective study included patients with primary breast cancer who were treated at centres in Lund and Malmö during 2008-2013. Clinicopathological predictors in the SUS nomogram were age, mode of detection, tumour size, multifocality, lymphovascular invasion and surrogate molecular subtype. Multiple imputation was used for missing data. Validation performance was assessed using AUC and calibration. RESULTS: The study included 2939 patients (1318 patients treated in Lund and 1621 treated in Malmö). Node-positive disease was detected in 1008 patients. The overall validation AUC was 0.74 (Lund cohort AUC: 0.75, Malmö cohort AUC: 0.73), and the calibration was satisfactory. Accepting a false-negative rate of 5 per cent for predicting N0, a possible SLNB reduction rate of 15 per cent was obtained in the overall cohort. CONCLUSION: The SUS nomogram provided acceptable power for predicting a disease-free axilla in the validation cohort. This tool may assist surgeons in identifying and counselling patients with a low risk of nodal metastasis on the omission of SLNB staging.

Nomograms for preoperative prediction of axillary nodal status in breast cancer.

BACKGROUND: Axillary staging in patients with breast cancer and clinically node-negative disease is performed by sentinel node biopsy (SLNB). The aim of this study was to integrate feasible preoperative variables into nomograms to guide clinicians in stratifying treatment options into no axillary staging for patients with non-metastatic disease (N0), SLNB for those with one or two metastases, and axillary lymph node dissection (ALND) for patients with three or more metastases. METHODS: Patients presenting to Skåne University Hospital, Lund, with breast cancer were included in a prospectively maintained registry between January 2009 and December 2012. Those with a preoperative diagnosis of nodal metastases were excluded. Patients with data on hormone receptor status, human epidermal growth factor receptor 2 and Ki-67 expression were included to allow grouping into surrogate molecular subtypes. Based on logistic regression analyses, nomograms summarizing the strength of the associations between the predictors and each nodal status endpoint were developed. Predictive performance was assessed using the area under the receiver operating characteristic (ROC) curve. Bootstrap resampling was performed for internal validation. RESULTS: Of the 692 patients eligible for analysis, 248 were diagnosed with node-positive disease. Molecular subtype, age, mode of detection, tumour size, multifocality and vascular invasion were identified as predictors of any nodal disease. Nomograms that included these predictors demonstrated good predictive abilities, and comparable performances in the internal validation; the area under the ROC curve was 0·74 for N0 versus any lymph node metastasis, 0·70 for one or two involved nodes versus N0, and 0·81 for at least three nodes versus two or fewer metastatic nodes. CONCLUSION: The nomograms presented facilitate preoperative decision-making regarding the extent of axillary surgery.

Completion axillary dissection can safely be omitted in screen detected breast cancer patients with micrometastases. A decade's experience from a single institution.

BACKGROUND: The need for completion axillary lymph node dissection (ALND) in breast cancer patients with micrometastases in the sentinel nodes (SNs) is controversial. The aim of this retrospective observational study is to determine if the method of detection of early breast cancer is predictive for additional positive nodes in patients with micrometastases in the SNs. METHODS: Between 2001 and 2011 a total of 1993 women with primary unilateral breast cancer had surgery at Skåne University Hospital, Lund. Of 1993 patients, 1458 had an SN biopsy and nearly all patients with micro- and macrometastases had ALND. RESULTS: Micrometastases defined as >0.2 mm/>200 cells and ≤2.0 mm were found in 62 of 757 screen-detected patients and in 81 of 701 patients with symptomatic breast cancer. Only 3 of the screen-detected patients with micrometastases, all with tumour size >15 mm (range 18-39 mm), had metastases in the completion ALND whereas this was found in 18 of the symptomatic patients with micrometastases (p = 0.01), (tumour size, range 10-30 mm). Logistic regression analysis adjusted for method of detection, tumour size and histological grade showed 5 times higher odds for further metastases in ALND in patients with symptomatic presentation vs. screen-detected breast cancer. CONCLUSION: Despite the small number of patients with micrometastases in this large cohort of breast cancer patients, these results support the contention that completion ALND can safely be omitted in screen-detected breast cancer patients with micrometastases in the SNs.