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.

Very low local recurrence rates after breast-conserving therapy: analysis of 8485 patients treated over a 28-year period.

The purpose of this study was to study the impact of changes in clinical practice on outcome in patients treated with breast-conserving therapy (BCT) over a period of 28 years. Patients with early invasive breast cancer, who were treated with BCT at the Netherlands Cancer Institute between 1980 and 2008, were studied. Clinical characteristics, treatment and outcome were compared between groups (1980-1987; 1988-1998; 1999-2008). The main endpoint analyzed was ipsilateral breast tumor recurrence (IBTR). 8485 patients with a median follow-up of 9 years (IQR 6-14 years) were analyzed. The cumulative 5- and 10-year IBTR incidences were, respectively, 2 and 5 % for the whole cohort and 4 and 9 % in patients ≤40 years. Young age was a significant risk factor for IBTR in multivariable analysis. IBTR-free interval was better for patients who received a RT boost (HR 0.65) or systemic therapy (HR 0.52). In later years, patients less often received a boost and more often underwent adjuvant systemic treatment. 761 patients (9.0 %) underwent a re-excision; the tumor resection margins were tumor free for 85 %. In later years (1999-2008), 89 % of patients had a tumor-free margin. The margin status of invasive carcinoma did not influence IBTR, DM rate, or OS. Between 1980 and 2008, locoregional control after BCT remained stable with low IBTR rates, even in young patients. These good results were achieved under the policy of accepting close or focally positive margins, indicating this is a safe approach. The results of this study may help in lowering the re-excision rates, which are high in many centers.

Evaluation of delineating the target volume by radiation therapists in breast cancer patients.

AIM: Breast radiotherapy accounts for a significant workload in radiotherapy departments. In 2015 it became clinical practice at the Netherlands Cancer Institute for radiation therapists (RTTs) to delineate the clinical target volume of the breast tissue (CTVbreast) and in 2017 axilla level I-II (CTVln12) according to a delineation atlas. All RTTs were trained and got individual feedback. The aim of this retrospective study was to investigate the variation between the CTVbreast with or without CTVln12 delineated by a trained group of radiation therapists and the clinical adjusted delineations by the radiation oncologist/physician assistant (RO/PA), in a large group of patients treated between January 2017 and June 2020. MATERIALS AND METHODS: 1012 computer tomography based delineations of CTVbreast and 146 of CTVln12 were collected from January 2017-June 2020. The RTT and RO/PA delineations were compared using the Dice coefficient and the 95th percentile Hausdorff Distance (95%HD). Statistical significance of the differences was tested using a Mann-Whitney test. RESULTS: Differences in CTVbreast delineations were small. A median Dice score of 1.00 for all years, where 83% of the patients had a Dice score > 0.99. For CTVln12 the magnitude of edits made by RO/PAs decreased over time, with the Dice increasing from a median of 0.87 in 2017 to 0.90 in 2020 (p = 0.031). The 95%HD decreased from a median of 0.93 cm in 2017 to 0.61 cm in 2020 (p = 0.051). CONCLUSIONS: This retrospective study shows that trained dedicated RTTs are capable in delivering the same quality delineations as RO/PAs. The low variability supports the increasing role of RTTs in the contouring process, likely making it more time efficient.

[Guideline 'Treatment of breast cancer 2008' (revision)]. / Richtlijn 'Behandeling van het mammacarcinoom 2008' (herziening).

The Dutch evidence-based guideline 'Treatment of breast cancer' has been revised, and integrated with the guideline 'Screening for and diagnosis of breast cancer'. The guideline can be found on www. oncoline.nl and on www.cbo.nl. The Internet programme 'Adjuvant!' (www.adjuvantonline.com) can be used to predict both the prognosis and the efficacy of systemic adjuvant therapy for each patient. The indications for adjuvant chemotherapy and endocrine therapy have been widened. The aim is to reduce the absolute probability of death by at least 4-5% within 10 years. The goal of neoadjuvant chemotherapy in operable breast cancer is to enable breast-conserving therapy for large tumours in relatively small breasts. One could consider transferring responsibility for follow-up after 5 years from the hospital to the screening organisation following mastectomy, to the family doctor following breast-conserving therapy, and to an outpatient clinic for hereditary tumours in carriers of gene mutation. Cessation of follow-up above the age of 75 could also be considered.

PET/CT with 18F-FDG predicts short-term outcome in stage II/III breast cancer patients upstaged to N2/3 nodal disease.

INTRODUCTION: 18F-FDG PET/CT has high positive predictive value for the detection of avid lymph node metastases in breast cancer patients. We analysed the effect of upstaging lymph nodes by PET/CT on short-term outcome in stage II/III breast cancer patients. PATIENTS AND METHODS: A total of 278 stage II/III primary breast cancer patients (mean age 48.9 years, range 19-75 years) were re-staged with 18F-FDG PET/CT before start of pre-operative systemic treatment (PST). Patients were divided in three groups based on risk for local recurrence: a low - (T2N0), intermediate - (T0-2N1 and T3N0) and a high-risk group (T0-3N2-3, T3N1 and T4). Within these groups we looked at local recurrence-free survival (LRFS), recurrence-free survival (RFS) and overall survival (OS) within the first 3 years of follow-up. RESULTS: With a median follow-up (FU) of 50 months the RFS, LRFS and OS were 87%, 88% and 92% respectively for the whole group. PET/CT upstaged 43 patients from the low- and intermediate risk group to the high-risk group, based on detection of ≥4 avid axillary nodes or occult N2/3-disease. Patients upstaged with PET/CT had more events for all three analyses compared to the original risk groups, which resulted in a significantly worse RFS (69.8%; p = 0.03) a nearly significantly worse LRFS (p = 0.052) and no effect in OS (p = 0.433). DISCUSSION: Additional PET/CT staging allows breast cancer patients to be treated according to the true stage, still stage II/III breast cancer patients upstaged to N2/3 by PET/CT have worse short-term outcome, despite adjustment of treatment, than patients staged high-risk with conventional imaging.

Long-term prognosis of patients with local recurrence after conservative surgery and radiotherapy for early breast cancer.

We have studied the long-term prognosis of 266 patients considered to have isolated local recurrence in the breast following conservative surgery and radiotherapy for early breast cancer. The median follow-up of the patients still alive after diagnosis of local relapse was 11.2 years. At 10 years from the date of salvage treatment, the overall survival rate for the 226 patients with invasive local recurrence was 39% (95% CI, 32-46), the distant recurrence-free survival rate was 36% (95% CI, 29-42), and the local control rate (i.e., survival without subsequent local recurrence or local progression) was 68% (95% CI, 62-75). Among patients with a local recurrence at or near the original tumour site a better distant disease-free survival was observed for patients with recurrences measuring 1cm or less, compared to those with larger recurrences. This suggests, though does not prove, that early detection of local recurrence can improve the treatment outcome but might as well point towards a different biologic behaviour, facilitating early detection.

Interobserver variability in the radiological assessment of response to chemotherapy in glioma.

OBJECTIVE: To assess the interobserver variability in the radiologic assessment of response to chemotherapy in patients with recurrent glioma. METHODS: Five clinicians with experience in the treatment and follow-up of patients with glioma measured tumor size in 20 pairs of CT and 20 pairs of MRI scans of 35 patients who had been treated with chemotherapy for recurrent glioma. Tumor size was defined as the product of the two largest perpendicular enhancing tumor diameters on the postcontrast images. To assess the interobserver variability in the measurements of tumor size, and in the classification according to the widely used Macdonald response criteria, intraclass correlation coefficients (ICC) and weighted kappa values were calculated. RESULTS: Substantial interobserver agreement was noted in the manual, two-dimensional measurements of tumor size on CT and MRI in patients treated with chemotherapy for recurrent glioma (overall ICC 0.64). Classification of response to chemotherapy according to the Macdonald criteria resulted in moderate interobserver agreement (overall weighted kappa 0.51). In 65% of evaluated CT and in 55% of evaluated MRI studies, no complete consensus was found for the categorical tumor response measurement. CONCLUSION: The radiologic assessment of response to chemotherapy in patients with recurrent glioma is susceptible to considerable interobserver variability. This underlines the difficulties that arise in scoring response to chemotherapy by conventional radiologic techniques.