Gene expression profiles in clinically T1-2N0 ER+HER2- breast cancer patients treated with breast-conserving therapy: their added value in case sentinel lymph node biopsy is not performed.

PURPOSE: Omitting sentinel lymph node biopsy (SLNB) in breast cancer treatment results in patients with unknown positive nodal status and potential risk for systemic undertreatment. This study aimed to investigate whether gene expression profiles (GEPs) can lower this risk in cT1-2N0 ER+ HER2- breast cancer patients treated with BCT. METHODS: Patients were included if diagnosed between 2011 and 2017 with cT1-2N0 ER+ HER2- breast cancer, treated with BCT and SLNB, and in whom GEP was applied. Adjuvant chemotherapy recommendations based on clinical risk status (Dutch breast cancer guideline of 2020 versus PREDICT v2.1) with and without knowledge on SLNB outcome were compared to GEP outcome. We examined missing adjuvant chemotherapy indications, and the number of GEPs needed to identify one patient at risk for systemic undertreatment. RESULTS: Of 3585 patients, 2863 (79.9%) had pN0 and 722 (20.1%) pN + disease. Chemotherapy was recommended in 1354 (37.8% guideline-2020) and 1888 patients (52.7% PREDICT). Eliminating SLNB outcome (n = 722) resulted in omission of chemotherapy recommendation in 475 (35.1% guideline-2020) and 412 patients (21.8% PREDICT). GEP revealed genomic high risk in 126 (26.5% guideline-2020) and 82 patients (19.9% PREDICT) in case of omitted chemotherapy recommendation in the absence of SLNB. Extrapolated to the whole group, this concerns 3.5% and 2.3%, respectively, resulting in the need for 28-44 GEPs to identify one patient at risk for systemic undertreatment. CONCLUSION: If no SLNB is performed, clinical risk status according to the guideline of 2020 and PREDICT predicts a very low risk for systemic undertreatment. The number of GEPs needed to identify one patient at risk for undertreatment does not justify its standard use.

Clinically node negative breast cancer patients undergoing breast conserving therapy, sentinel lymph node procedure versus follow-up: a Dutch randomized controlled multicentre trial (BOOG 2013-08).

BACKGROUND: Studies showed that axillary lymph node dissection can be safely omitted in presence of positive sentinel lymph node(s) in breast cancer patients treated with breast conserving therapy. Since the outcome of the sentinel lymph node biopsy has no clinical consequence, the value of the procedure itself is being questioned. The aim of the BOOG 2013-08 trial is to investigate whether the sentinel lymph node biopsy can be safely omitted in clinically node negative breast cancer patients treated with breast conserving therapy. METHODS: The BOOG 2013-08 is a Dutch prospective non-inferiority randomized multicentre trial. Women with pathologically confirmed clinically node negative T1-2 invasive breast cancer undergoing breast conserving therapy will be randomized for sentinel lymph node biopsy versus no sentinel lymph node biopsy. Endpoints include regional recurrence after 5 (primary endpoint) and 10 years of follow-up, distant-disease free and overall survival, quality of life, morbidity and cost-effectiveness. Previous data indicate a 5-year regional recurrence free survival rate of 99% for the control arm and 96% for the study arm. In combination with a non-inferiority limit of 5% and probability of 0.8, this result in a sample size of 1.644 patients including a lost to follow-up rate of 10%. Primary and secondary endpoints will be reported after 5 and 10 years of follow-up. DISCUSSION: If the sentinel lymph node biopsy can be safely omitted in clinically node negative breast cancer patients undergoing breast conserving therapy, this study will cost-effectively lead to a decreased axillary morbidity rate and thereby improved quality of life with non-inferior regional control, distant-disease free survival and overall survival. TRIAL REGISTRATION: The BOOG 2013-08 study is registered in ClinicalTrials.gov since October 20, 2014, Identifier: NCT02271828. https://clinicaltrials.gov/ct2/show/NCT02271828.

Quality assurance of radiation therapy after breast-conserving surgery among patients in the BOOG 2013-08 trial.

BACKGROUND AND PURPOSE: In the BOOG 2013-08 trial (NCT02271828), cT1-2N0 breast cancer patients were randomized between breast conserving surgery with or without sentinel lymph node biopsy (SLNB) followed by whole breast radiotherapy (WBRT). While awaiting primary endpoint results (axillary recurrence rate), this study aims to perform a quality assurance analysis on protocol adherence and (incidental) axillary radiation therapy (RT) dose. MATERIALS AND METHODS: Patients were enrolled between 2015 and 2022. Data on prescribed RT and (in 25% of included patients) planning target volumes (PTV) parameters were recorded for axillary levels I-IV and compared between treatment arms. Multivariable linear regression analysis was performed to determine prognostic variables for incidental axillary RT dose. RESULTS: 1,439/1,461 included patients (98.5%) were treated according to protocol and 87 patients (5.9%) received regional RT (SLNB 10.9%, no-SLNB 1.5 %). In 326 patients included in the subgroup analysis, the mean incidental PTV dose at axilla level I was 59.5% of the prescribed breast RT dose. In 5 patients (1.5%) the mean PTV dose at level I was ≥95% of the prescribed breast dose. No statistically or clinically significant differences regarding incidental axillary RT dose were found between treatment arms. Tumour bed boost (yes/no) was associated with a higher incidental mean dose in level I (R2 = 0.035, F(6, 263) = 1.532, p 0.168). CONCLUSION: The results indicate that RT-protocol adherence was high, and that incidental axillary RT dose was low in the BOOG 2013-08 trial. Potential differences between treatmentarms regarding the primary endpoint can thus not be attributed to different axillary radiation doses.

CSF neurofilament and N-acetylaspartate related brain changes in clinically isolated syndrome.

BACKGROUND: Axonal damage is considered a major cause of disability in multiple sclerosis (MS) and may start early in the disease. Specific biomarkers for this process are of great interest. OBJECTIVE: To study if cerebrospinal fluid (CSF) biomarkers for axonal damage reflect and predict disease progression already in the earliest stages of the disease, that is, in clinically isolated syndrome (CIS). METHODS: We assessed CSF levels of neurofilament heavy (NFH), neurofilament light (NFL) and N-acetylaspartate (NAA) in 67 patients with CIS and 18 controls with neuropsychiatric diseases of non-inflammatory aetiology (NC). Patients with CIS underwent baseline magnetic resonance imaging (MRI) at 3T, and a follow-up MRI after 1 year was obtained in 28 of them. RESULTS: Compared with NC, patients with CIS had higher NFH (p=0.05) and NFL (p<0.001) levels. No significant group differences were found for NAA. Patients' NFH levels correlated with physical disability (r=0.304, p<0.05) and with change in brain volume over 1 year of follow-up (r=-0.518, p<0.01) but not with change in T2 lesion load. CONCLUSION: Our results confirm increased neurofilament levels already in CIS being related to the level of physical disability. The association of NFH levels with brain volume but not lesion volume changes supports the association of these markers with axonal damage.

Does the subtype of breast cancer affect the diagnostic performance of axillary ultrasound for nodal staging in breast cancer patients?

INTRODUCTION: Imaging findings can be affected by histopathological characteristics, such as breast cancer subtypes. The aim was to determine whether the diagnostic performance, in particular negative predictive value (NPV), of axillary US differs per subtype of breast cancer. METHODS: All patients diagnosed between 2008 and 2016 in our hospital with primary invasive breast cancer and an axillary US prior to axillary surgery were included. Histopathology of axillary surgery specimens served as gold standard. The NPV, sensitivity, specificity, positive predictive value (PPV) and accuracy of the axillary US were determined for the overall population and for each subtype (ER+/PR+HER2-,HER2+, triple negative tumors). The Chi-square test was used to determine the difference in diagnostic performance parameters between the subtypes. RESULTS: A total of 1094 breast cancer patients were included. Of these, 35 were diagnosed with bilateral breast cancer, resulting in 1129 cancer cases. Most common subtype was ER+/PR+HER2- in 858 cases (76.0%), followed by 150 cases of HER2+ tumors (13.3%) and 121 cases of triple negative tumors (10.7%). Sensitivity, specificity and accuracy of axillary US did not significantly differ between the subtypes. There was a significant difference for NPV between triple negative tumors and HER2+ tumors (90.3% vs. 80.2%, p = 0.05) and between HER2+ and ER/PR+HER2- tumors (80.2% vs. 87.2%, p = 0.04). CONCLUSION: There was no significant difference in the diagnostic performance of axillary US between the subtypes, except for NPV. This was highest in triple negative subtype and lowest in HER2+ tumors. This can be explained by the difference in prevalence of axillary lymph node metastases in our cohort.

TNM classification and the need for revision of pN3a breast cancer.

BACKGROUND: According to the seventh edition of tumour-node-metastasis (TNM) classification, pN3a status in breast cancer patients consists of presence of an infraclavicular lymph node metastasis (LNM) and/or presence of ≥10 axillary LNMs. The aim of this study was to determine whether prognosis of pN3a based on at least an infraclavicular LNM differs from ≥10 axillary LNMs. METHODS: Data were obtained from the Netherlands Cancer Registry. All patients were diagnosed between 2005 and 2008 with primary invasive epithelial breast cancer and pN2a or pN3a status as pathologic result. Patients with pN3a were subdivided in pN3a based on at least an infraclavicular LNM or ≥10 axillary LNMs. Disease-free survival (DFS) included any local, regional or contralateral recurrence, distant metastasis or death within 5 years. Kaplan-Meier curves provided information on 5-year DFS and 8-year overall survival (OS). In addition, Cox proportional hazards model was used to measure the effect of relevant clinicopathological variables on DFS and OS. RESULTS: A total of 3400 patients with pN2a and 1788 patients with pN3a were included. In 83 patients, pN3a was based on at least an infraclavicular LNM (4.6%) and in 1705 patients because of ≥10 axillary LNMs (95.4%). After multivariable analyses, DFS and OS were inferior in patients with pN3a based on ≥10 axillary LNMs compared to infraclavicular LNM (DFS 48.8% versus 63.8%, hazard ratio [HR] 1.59, p = 0.036; OS 46.6% versus 63.9%, HR 1.46, p = 0.042). Furthermore, pN2a and pN3a based on infraclavicular LNM had comparable DFS and OS. CONCLUSION: PN3a status based on an at least an infraclavicular LNM is rare, yet its prognosis is superior to ≥10 axillary LNMs. Reclassification of infraclavicular LNM in the next TNM should therefore be considered into pN2a.