Background

Background Sentinel node biopsy (SNB) is the standard procedure for axillary staging in patients with clinically lymph node negative invasive breast cancer. Completion axillary lymph node dissection (c-ALND) may not be necessary for all patients as a significant number of patients have no further metastases in non-sentinel nodes (non-SN) and c-ALND may not improve survival. The first aim of our study is to identify clinicopathological determinants associated with non-SN metastases. The second aim is to determine the impact of the number of sentinel node (SN) with macro-metastases and the type of SN metastases on metastatic involvement in non-SN. Methods This is a retrospective study of 602 patients with primary invasive breast cancer operated on with SNB and c-ALND in Lund and Malmö during 2008–2013. All these patients had micro- and/or macro-metastases in SNs. Information was retrieved from the national Information Network for Cancer Care (INCA). The risk of metastases to non-SNs were analyzed in relation to clinicopathological determinants such as age, screening mammography, tumour size, tumour type, histological grade, estrogen status, progesterone status, HER2 status, multifocality and lymphovascular invasion. Additionally, we compared the association between the number of the SN and the type of metastases in SN with the risk of metastases to non-SNs. Binary logistic regression was used, yielding odds ratios (OR) with 95% confidence intervals (CI). Results We found that 211 patients (35%) had metastases in non-SNs and 391 patients (65%) had no metastases in non-SNs. Lobular type (18%) of breast cancer (1.73; 1.0 1-2.97) and multifocal (31.3%) tumours (2.20; 1.41–3.44) had a high risk of non-SNs metastases. As compared to only micro-metastases, the presence of macro-metastases in SNs was associated with a high risk of metastases to non-SNs (4.91; 3.01–8.05). The number of SN with macro-metastases, regardless of the number of SNs removed by surgery, increases the risk of finding non-SNs with metastases. The total number of SN removed by surgery had no impact on diagnosis of metastases in non-SNs. No statistically significant associations were observed regarding other studied determinants. Conclusion We conclude in the present study that lobular cancer and multifocal tumours were associated with a high risk of non-SN involvement. The presence of the macro-metastases in SNs and the number of SN with macro-metastases has a positive association with presence of metastases in non-SNs. The total number of SNs removed by surgery had no impact on finding metastases in non-SNs. These factors may be valuable considering whether or not to omit c-ALND.

BackgroundAxillary lymph node status is one of the most important prognostic factors for breast cancer. The aim of this study was to determine predictive factors for metastasis to sentinel node (SN) in primary invasive breast cancer.MethodThis is a study of 3979 patients with primary breast cancer during 2008–2013 in Malmö and Lund scheduled for surgery and included in the information retrieved from Information Network for Cancer Care (INCA). The final study population included 2552 patients with primary invasive breast cancer. The risk of metastases to SN were examined in relation to potential clinicopathological factors such as age, screening mammography, tumor size, tumor type, histological grade, estrogen status, progesterone status, Her-2 status, multifocality, and lymphovascular invasion. Binary logistic regression was used; adjusted analyses yielded odds ratio (OR) with 95% confidence interval.ResultsTumors detected by mammography screening were less likely to be associated with metastases to SN compared to those not found by mammography screening (0.63; 0.51–0.80). Negative hormonal status for estrogen associated with lower risk for SN metastases compared to tumor with positive estrogen status (0.64; 0.42–0.99). Tumors with a size more than 20 mm had higher risk to metastasize to SN (1.84; 1.47–2.33) compared to tumors less than 20 mm. Multifocality (1.90; 1.45–2.47) and lymphovascular invasion (3.74; 2.66–5.27) were also strong predictive factors for SN metastases.ConclusionSN metastasis is less likely to occur in women with invasive breast cancer diagnosed by screening mammogram. Tumors with negative estrogen status are associated with low risk for SN metastases. Tumors larger than 20 mm, multifocality, or lymphovascular invasion are also factors associated with high risk for SN metastases.