Toward omitting sentinel lymph node biopsy after neoadjuvant chemotherapy in patients with clinically node-negative breast cancer.

BACKGROUND: The nodal positivity rate after neoadjuvant chemotherapy (ypN+) in patients with clinically node-negative (cN0) breast cancer is low, especially in those with a pathological complete response of the breast. The aim of this study was to identify characteristics known before surgery that are associated with achieving ypN0 in patients with cN0 disease. These characteristics could be used to select patients in whom sentinel lymph node biopsy may be omitted after neoadjuvant chemotherapy. METHODS: This cohort study included patients with cT1-3 cN0 breast cancer treated with neoadjuvant chemotherapy followed by breast surgery and sentinel node biopsy between 2013 and 2018. cN0 was defined by the absence of suspicious nodes on ultrasound imaging and PET/CT, or absence of tumour cells at fine-needle aspiration. Univariable and multivariable logistic regression analyses were performed to determine predictors of ypN0. RESULTS: Overall, 259 of 303 patients (85.5 per cent) achieved ypN0, with high rates among those with a radiological complete response (rCR) on breast MRI (95·5 per cent). Some 82 per cent of patients with hormone receptor-positive disease, 98 per cent of those with triple-negative breast cancer (TNBC) and all patients with human epidermal growth factor receptor 2 (HER2)-positive disease who had a rCR achieved ypN0. Multivariable regression analysis showed that HER2-positive (odds ratio (OR) 5·77, 95 per cent c.i. 1·91 to 23·13) and TNBC subtype (OR 11·65, 2·86 to 106·89) were associated with ypN0 status. In addition, there was a trend toward ypN0 in patients with a breast rCR (OR 2·39, 0·95 to 6·77). CONCLUSION: The probability of nodal positivity after neoadjuvant chemotherapy was less than 3 per cent in patients with TNBC or HER2-positive disease who achieved a breast rCR on MRI. These patients could be included in trials investigating the omission of sentinel node biopsy after neoadjuvant chemotherapy.

Major Reduction in Axillary Lymph Node Dissections After Neoadjuvant Systemic Therapy for Node-Positive Breast Cancer by combining PET/CT and the MARI Procedure.

BACKGROUND: Axillary lymph node dissection (ALND) is frequently performed for node-positive (cN+) breast cancer patients. Combining positron emission tomography/computed tomography (PET/CT) before-NST and the MARI (marking axillary lymph nodes with radioactive iodine seeds) procedure after neoadjuvant systemic therapy (NST) has the potential for avoiding unnecessary ALNDs. This report presents the results from implementation of this strategy. METHODS: All breast cancer patients treated with NST at the Netherlands Cancer Institute who underwent a PET/CT and the MARI procedure from July 2014 to July 2017 were included in the study. All the patients underwent tailored axillary treatment according to a protocol based on the combined results of PET/CT before NST and the MARI procedure after NST. With this protocol, patients showing one to three FDG-avid axillary lymph nodes (ALNs) on PET/CT (cN<4) and a tumor-negative MARI node receive no further axillary treatment. All cN (<4) patients with a tumor-positive MARI node receive locoregional radiotherapy, as well as patients with four or more FDG-avid ALNs [cN(4+)] and a tumor-negative MARI node after NST. An ALND is performed only for cN(4+) patients with a tumor-positive MARI node. RESULTS: The data of 159 patients who received a PET/CT before NST and a MARI procedure after NST were analyzed. Of these patients, 110 had one to three FDG-avid ALNs and 49 patients showed four or more FDG-avid ALNs on PET/CT before NST. For 130 patients (82%), ALND was omitted. Locoregional radiotherapy was administered to 91 patients (57%), and 39 patients (25%) received no further axillary treatment. CONCLUSION: Combining pre-NST axillary staging with PET/CT and post-NST staging with the MARI procedure resulted in an 82% reduction of ALNDs for cN + breast cancer patients.

Combined PET-CT and axillary lymph node marking with radioactive iodine seeds (MARI procedure) for tailored axillary treatment in node-positive breast cancer after neoadjuvant therapy.

BACKGROUND: The treatment of axillary lymph node metastases after neoadjuvant systemic therapy (NST) remains debatable and axillary lymph node dissection (ALND) is still the standard of care. Marking axillary lymph nodes with radioactive iodine seeds (MARI procedure) is accurate in restaging the axilla after NST (false-negative rate 7 per cent). Here, the potential of tailored axillary treatment, determined by combining the results of PET-CT before NST with those of the MARI procedure after NST, was analysed. METHODS: A cohort of axillary node-positive patients was used to construct a hypothetical treatment algorithm based on a combination of PET-CT and the MARI procedure. In the algorithm, the number of fluorodeoxyglucose (FDG)-avid axillary lymph nodes (1-3 versus 4 or more) before NST and the tumour status of the MARI node (positive versus negative) after NST were used to tailor axillary treatment. All patients in the cohort underwent ALND, allowing estimation of potential overtreatment and undertreatment. RESULTS: A total of 93 patients were included in the study. Between one and three FDG-avid axillary lymph nodes were observed in 59 patients, and four or more in 34 patients. The MARI node was tumour-negative in 32 patients and showed residual disease in 61. Treatment according to the constructed algorithm would have resulted in 74 per cent of patients avoiding an ALND, with potential undertreatment in three patients (3 per cent) and overtreatment in 16 (17 per cent). CONCLUSION: Tailored axillary treatment after NST in node-positive patients, by combining PET-CT before NST and the MARI procedure after NST, has the potential for ALND to be avoided in 74 per cent of patients.

Identifying pathologic complete response of the breast after neoadjuvant systemic therapy with ultrasound guided biopsy to eventually omit surgery: Study design and feasibility of the MICRA trial (Minimally Invasive Complete Response Assessment).

PURPOSE: Improvements in neoadjuvant systemic therapy (NST) for breast cancer patients have led to increasing rates of pathologic complete response (pCR). The MICRA trial (NTR6120) aims at identifying pCR with post-NST biopsies. Here, we report the study design and feasibility. METHODS: The MICRA-trial is a multi-center prospective cohort study. Patients with a pre-NST placed marker and radiologic complete (rCR) or partial response on MRI after NST are eligible for inclusion. Ultrasound guided biopsy of the original tumor area is performed. Pathology results of the biopsies and surgery specimens are compared. The primary endpoint is false-negative rate of biopsies in identifying pCR. RESULTS: During the first year of the trial 58 patients with rCR were included. One patient was a screening failure and excluded for analysis. Twenty-one percent had hormone receptor (HR)+/HER2- tumors, 21% HR+/HER2+ tumors, 18% HR-/HER2+ tumors and 40% TN tumors. Overall pCR was 68%. In seven patients biopsies could not be obtained: in 6 patients, the marker could not be identified on ultrasound in the OR and in 1 patient there were technical difficulties. A median of eight biopsies was obtained (range 4-9). The median of histopathological representative biopsies was 4 (range 1-8). CONCLUSION: Ultrasound guided biopsy of the breast in patients with excellent response on MRI after NST is feasible. Accuracy results of the MICRA trial will be presented after inclusion of 525 patients to determine if ultrasound guided biopsy is an accurate alternative to surgical resection for assessment of pCR after NST.

The intraoperative assessment of sentinel nodes - Standards and controversies.

Intraoperative assessment of sentinel lymph nodes (SLNs) has the advantage of allowing breast cancer patients with tumor-positive SLNs to avoid a second surgery by immediately proceeding to axillary lymph node dissection (ALND). However, there are several reasons why the use of intraoperative assessment should be questioned. Whereas ALND was traditionally advised for all breast cancer patients with tumor-positive lymph nodes for axillary staging and locoregional control, more recent studies have demonstrated safety of omitting ALND in a substantial number of patients. In addition, there are concerns about the accuracy of intraoperative assessment methods including frozen section analysis, touch preparation cytology and one-step nucleic acid amplification. Moreover, intraoperative assessment of SLNs denies patients the opportunity to contribute to their treatment planning. In our opinion, intraoperative assessment of axillary lymph nodes should be reserved for patients who still have a strict indication for ALND. Patients with clinical node negative disease (cN0) and one or two positive SLNs can be safely treated with breast conserving surgery and radiotherapy. There has been more controversy for cN0 patients who are treated with mastectomy since radiotherapy is not routinely administered in these patients. However, there is increasing evidence that ALND may be omitted in patients undergoing mastectomy who have a low tumor-burden in their SLNs. Therefore, we defend the position that in cN0 patients undergoing mastectomy, SLNB should be performed and full pathologic evaluation of the SLN should be awaited. In cN0 patients undergoing neoadjuvant systemic therapy (NST) intraoperative assessment of SLNs can be omitted since ALND will not provide therapeutic benefit. It is being hypothesized that patients with limited axillary disease prior to NST who remain node-positive after NST could be treated safely with axillary radiotherapy instead of ALND. In these patients, omitting intraoperative assessment might be a reasonable option. In patients with extensive nodal disease prior to NST intraoperative assessment of axillary lymph nodes should be performed.

The use of radioactive iodine-125 seed localization in patients with non-palpable breast cancer: a comparison with the radioguided occult lesion localization with 99m technetium.

BACKGROUND: Radioactive Seed Localization with a radioactive iodine-125 seed (RSL) and Radioguided Occult Lesion Localization with 99mTechnetium colloid (ROLL) are both attractive alternatives to wire localization for guiding breast conserving surgery (BCS) of non-palpable breast cancer. The aim of this study was to evaluate and compare the efficacy of RSL and ROLL. METHODS: We retrospectively analyzed 387 patients with unifocal non-palpable ductal carcinoma in situ (DCIS) or invasive carcinoma treated with BCS at the Netherlands Cancer Institute. In total 403 non-palpable lesions were localized either by RSL (N = 128) or by ROLL (N = 275). Primary outcome measures were positive margins and re-excision rates; the secondary outcome measure was weight of the specimen. RESULTS: Pre-operative mammography or ultrasound showed similar sizes of DCIS and invasive tumours in both RSL and ROLL groups. In the RSL group, more lesions were DCIS (58%) than in the ROLL group, where 32% of the lesions were pure DCIS. The proportions of focally positive margins (11% vs. 10%) and more than focally positive margins (9% vs. 9%) were comparable between the RSL and the ROLL group, resulting in the same re-excision rate in both RSL and ROLL groups (9% vs. 10%). For DCIS lesions, the specimen weight was significantly lower in the RSL group than in the ROLL group after adjusting for tumour size on mammography (12 g; 95% CI 2.6-21). CONCLUSION: Margin status and re-excision rates were comparable for RSL and ROLL in patients with non-palpable breast lesions. Because of the significant lower weight of the resected specimen in DCIS, the feasibility of position verification of the I-125 seed and more convenient logistics, we favour RSL over ROLL to guide breast-conserving therapy.