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Rationale and Objectives To test the ability of quantitative measures from preoperative Dynamic Contrast Enhanced MRI (DCE-MRI) to predict, independently and/or with the Katz pathologic nomogram, which breast cancer patients with a positive sentinel lymph node biopsy will have ≥ 4 positive axillary lymph nodes upon completion axillary dissection. Methods and Materials A retrospective review was conducted to identify clinically node-negative invasive breast cancer patients who underwent preoperative DCE-MRI, followed by sentinel node biopsy with positive findings and complete axillary dissection (6/2005 – 1/2010). Clinical/pathologic factors, primary lesion size and quantitative DCE-MRI kinetics were collected from clinical records and prospective databases. DCE-MRI parameters with univariate significance (p < 0.05) to predict ≥ 4 positive axillary nodes were modeled with stepwise regression and compared to the Katz nomogram alone and to a combined MRI-Katz nomogram model. Results Ninety-eight patients with 99 positive sentinel biopsies met study criteria. Stepwise regression identified DCE-MRI total persistent enhancement and volume adjusted peak enhancement as significant predictors of ≥4 metastatic nodes. Receiver operating characteristic (ROC) curves demonstrated an area under the curve (AUC) of 0.78 for the Katz nomogram, 0.79 for the DCE-MRI multivariate model, and 0.87 for the combined MRI-Katz model. The combined model was significantly more predictive than the Katz nomogram alone (p = 0.003). Conclusion Integration of DCE-MRI primary lesion kinetics significantly improved the Katz pathologic nomogram accuracy to predict presence of metastases in ≥ 4 nodes. DCE-MRI may help identify sentinel node positive patients requiring further localregional therapy.

BackgroundWhile breast radiotherapy typically includes regional nodal basins, the treatment of the internal mammary nodes (IMN) has been controversial due to concern for long-term cardiac toxicity. For high risk patients where IMN treatment is warranted, there is limited data with regards to the degree of heart sparing conferred by modern techniques. In this study, we sought to analyze the specific heart sparing metrics conferred by deep inspiration breath hold (DIBH) in the setting of IMN irradiation.MethodsFrom 2012 to 2015, 168 consecutive patients were treated with adjuvant left-sided radiotherapy using DIBH. Retrospective review identified 49 patients who received nodal irradiation, either to a supraclavicular field (SCF) and IMN (16), or to the SCF alone (33). Cardiac mean dose and dose volumes were calculated from free breathing (FB) and DIBH treatment plans, and compared by Wilcoxon signed-rank and Mann–Whitney U tests.ResultsDIBH achieved significant reductions in mean heart dose (p < 0.001) in both the IMN treated group from 6.73 Gy to 2.79 Gy (− 56.4%) and the IMN untreated group from 4.77 Gy to 1.55 Gy (− 63.7%). There was a 7.3% difference in relative reduction that was not statistically significant (p = 0.216). Relative reductions in heart dose volume measures were all significantly lower for IMN-irradiated patients (p ≤ 0.012), with the greatest deficits at V5 that gradually diminish with increasing dose (V25).ConclusionsThe relative heart sparing benefits of the DIBH technique are retained even with IMN inclusion. However, the addition of IMN irradiation is associated with an intrinsically greater heart dose, which translates to an estimated 9.2% proportional increase in the risk of a subsequent major coronary event. In the setting of effective cardiac sparing techniques, clinicians should take these considerations into account to guide when IMN treatment is warranted.

Purpose: To determine if dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) peak enhancement (PE) of primary breast cancer can predict the presence of lymph node extracapsular extension (LNECE) in patients with axillary metastatic disease. Materials and Methods:In all, 167 patients treated with radiotherapy for invasive breast cancer from January 1, 2006 to November 1, 2007 were retrospectively identified. Patients with DCE-MRI and surgical axillary staging were included in this study. PE of primary tumors was compared according to axillary nodal status: negative, positive without LNECE, or positive with LNECE. A receiver operator characteristic curve (ROC) was plotted to determine accuracy of PE to predict LNECE.Results: Forty-six patients met the study criteria. Thirtytwo (70%) were node-negative, 9 (19%) were node-positive without LNECE, and 5 (11%) were node-positive with LNECE. PE was greater for patients with LNECE (mean 365%) compared to node-positive patients without LNECE (mean 183%) P ¼ 0.05 and node-negative patients (mean 144%) P ¼ 0.0012. Area under the ROC curve was 0.93.Conclusion: DCE-MRI PE may be a surrogate marker for LNECE. If validated, DCE-MRI may provide noninvasive kinetic information informing axillary nodal status for patients who receive chemotherapy prior to surgical axillary staging or forego axillary dissection after a positive sentinel node biopsy.