BackgroundPathological complete response (pCR) is the ultimate response in breast cancer patients treated with neoadjuvant chemotherapy (NCT). It might be a surrogate outcome for disease-free survival (DFS) and overall survival (OS). We studied the effect of clinical tumor stage (cT-stage) on tumor pCR and the effect of pCR per cT-stage on 5-year OS and DFS.MethodsUsing the Netherlands Cancer Registry, all primary invasive breast cancer patients treated with NCT from 2005 until 2008 were identified. Univariable logistic regression analysis was performed to evaluate the effect of cT-stage on pCR, stepwise logistic regression analysis to correct for potential confounders and Kaplan–Meier survival analyses to calculate OS and DFS after five years.ResultsIn 2366 patients, overall pCR rate was 21%. For cT1, cT2, cT3, and cT4, pCR rates were 31, 22, 18, and 17%, respectively. Lower cT-stage (cT1-2 vs cT3-4) was a significant independent predictor of higher pCR rate (p < 0.001, OR 3.15). Furthermore, positive HER2 status (p < 0.001, OR 2.30), negative estrogen receptor status (p = 0.062, OR 1.69), and negative progesterone receptor status (p = 0.008, OR 2.27) were independent predictors of pCR. OS and DFS were up to 20% higher in patients with cT2-4 tumors with pCR versus patients without pCR. DFS was also higher for cT1 tumors with pCR.ConclusionsThe most important predictor of pCR in breast cancer patients is cT-stage: lower cT-stages have significantly higher pCR rates than higher cT-stages. Patients with cT2-4 tumors achieving pCR have higher OS and DFS compared to patients not achieving pCR.

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Breast cancer guidelines advise sentinel lymph node biopsy (SLNB) in patients with ductal carcinoma in situ (DCIS) on core biopsy at high risk of invasive cancer or in case of mastectomy. This study investigates the incidence of SLNB and SLN metastases and the relevance of indications in guidelines and literature to perform SLNB in order to validate whether SLNB is justified in patients with DCIS on core biopsy in current era. Clinically node negative patients diagnosed from 2004 to 2013 with only DCIS on core needle biopsy were selected from a national database. Incidence of SLN biopsy and metastases was calculated. With Fisher exact tests correlation between SLNB indications and actual presence of SLN metastases was studied. Further, underestimation rate for invasive cancer and correlation with SLN metastases was analysed. 910 patients were included. SLNB was performed in 471 patients (51.8 %): 94.5 % had pN0, 3.0 % pN1mi and 2.5 % pN1. Patients undergoing mastectomy had 7 % SLN metastases versus 3.5 % for breast conserving surgery (BCS) (p = 0.107). The only factors correlating to SLN metastases were smaller core needle size (p = 0.01) and invasive cancer (p < 0.001). Invasive cancer was detected in 16.7 % by histopathology with 15.6 % SLN metastases versus only 2 % in pure DCIS. SLNB showed metastases in 5.5 % of patients; 3.5 % in case of BCS (any histopathology) and 2 % when pure DCIS was found at definitive histopathology (BCS and mastectomy). Consequently, SLNB should no longer be performed in patients diagnosed with DCIS on core biopsy undergoing BCS. If definitive histopathology shows invasive cancer, SLNB can still be considered after initial surgery.

BackgroundThe main purpose was to investigate the correlation between magnetic resonance imaging (MRI)-based response patterns halfway through neoadjuvant chemotherapy and immunotherapy (NAC) and pathological tumor response in patients with breast cancer. Secondary purposes were to compare the predictive value of MRI-based response patterns measured halfway through NAC and after NAC and to measure interobserver variability.MethodsAll consecutive patients treated with NAC for primary invasive breast cancer from 2012 to 2015 and who underwent breast MRI before, halfway through (and after) NAC were included. All breast tumors were reassessed on MRI by two experienced breast radiologists and classified into six patterns: type 0 (complete radiologic response); type 1 (concentric shrinkage); type 2 (crumbling); type 3 (diffuse enhancement); type 4 (stable disease); type 5 (progressive disease). Percentages of tumors showing pathological complete response (pCR), > 50% tumor reduction and > 50% tumor diameter reduction per MRI-based response pattern were calculated. Correlation between MRI-based response patterns and pathological tumor reduction was studied with Pearson’s correlation coefficient, and interobserver agreement was tested with Cohen’s Kappa.ResultsPatients (n = 76; mean age 53, range 29–72 years) with 80 tumors (4 bilateral) were included. There was significant correlation between these MRI-based response patterns halfway through NAC and tumor reduction on pathology assessment (reader 1 r = 0.33; p = 0.003 and reader 2 r = 0.45; p < 0.001). Type-0, type-1 or type-2 patterns halfway through NAC showed highest tumor reduction rates on pathology assessment, with > 50% tumor reduction in 90%, 78% and 65% of cases, respectively. In 83% of tumors with type 0 halfway through NAC, pathology assessment showed pCR. There was no significant correlation between MRI-based response patterns after NAC and tumor reduction rates on pathology assessment (reader 1 r = − 0.17; p = 0.145 and reader 2 r = − 0.17; p = 0.146). In 41% of tumors with type 0 after NAC, pathology assessment showed pCR.ConclusionMRI-based response patterns halfway through NAC can predict pathologic response more accurately than MRI-based response patterns after NAC. Complete radiological response halfway NAC is associated with 83% pCR, while complete radiological response after NAC seems to be correct in only 41% of cases.Electronic supplementary materialThe online version of this article (10.1186/s13058-018-0950-x) contains supplementary material, which is available to authorized users.

Purpose Our purpose in this study was to assess the added clinical value of hybrid 18 F-FDG-PET/MRI compared to conventional imaging for locoregional staging in breast cancer patients undergoing neoadjuvant chemotherapy (NAC). Methods In this prospective study, primary invasive cT2-4 N0 or cT1-4 N+ breast cancer patients undergoing NAC were included. A PET/MRI breast protocol was performed before treatment. MR images were evaluated by a breast radiologist, blinded for PET images. PET images were evaluated by a nuclear physician. Afterwards, a combined PET/MRI report was written. PET/MRI staging was compared to conventional imaging, i.e., mammography, ultrasound and MRI. The proportion of patients with a modified treatment plan based on PET/MRI findings was analyzed.Results A total of 40 patients was included. PET/MRI was of added clinical value in 20.0% (8/40) of patients, changing the treatment plan in 10% and confirming the malignancy of suspicious lesions on MRI in another 10%. In seven (17.5%) patients radiotherapy fields were extended because of additional or affirmative PET/MRI findings being lymph node metastases (n = 5) and sternal bone metastases (n = 2). In one (2.5%) patient radiotherapy fields were reduced because of fewer lymph node metastases on PET/MRI compared to conventional imaging. Interestingly, all treatment changes were based on differences in number of lymph nodes suspicious for metastasis or number of distant metastasis, whereas differences in intramammary tumor extent were not observed. Conclusion Prior to NAC, PET/MRI shows promising results for locoregional staging compared to conventional imaging, changing the treatment plan in 10% of patients and potentially replacing PET/CT or tissue sampling in another 10% of patients.