Changes in expression of breast cancer tumor biomarkers between primary tumors and corresponding metastatic sites: common patterns and relationships with survival.

PURPOSE: In metastatic breast cancer, differences in expression patterns of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2) between the primary tumor (PT) and metastatic site (MET) have been reported. However, there is limited understanding of the relationship of tumor subtype discordance and overall survival (OS). We evaluated patterns of ER/PR/HER2 in PTs and corresponding METs and assessed the relationship between these patterns and OS. METHODS: Patients diagnosed at our center with metastatic breast cancer (2011-2020) were included. ER/PR were stratified as < 1%/1-10%/ > 10% by immunohistochemistry and HER2 as positive/negative by immunohistochemistry/FISH. Tumor subtypes were classified as ER or PR + /HER2-, HER2+ , or triple-negative. Biomarker discordance data from PTs to METs were analyzed for expression patterns. OS was assessed. RESULTS: Of 254 patients, 41 (16.1%) had synchronous and 213 (83.9%) had metachronous METs. Category change of ER/PR/HER2 expression was observed in 56 (22.0%), 117 (40.5%), and 30 (11.8%) patients, respectively. Tumor subtype changed in 56 (22.0%) patients. We identified a difference between PT and MET from ER > 10% to ER < 1% (n = 28,16.2% p < 0.01); PR > 10% to PR < 1% (n = 54,48.2%, p < 0.001); PR > 10% to PR 1-10% (n = 18,16.1%, p < 0.001), and ER or PR+/HER2- to triple-negative (n = 19,13.0%, p = 0.03). In log-rank analysis, change from an ER or PR+/HER2- (5-year OS 88.6%) PT to a HER2+(67.5%) or triple-negative (54.6%) MET was associated with decreased survival (p < 0.01); however, in multivariate analysis, discordant biomarker expression was not associated with decreased survival (p > 0.05). CONCLUSION: Tumor expression of ER/PR/HER2 can differ between the PT and MET. Loss of ER/PR expression is common and may be related to worse survival. Routine assessment of MET tumor markers could inform prognosis and therapeutic decision-making.

Patterns of completion axillary dissection for patients with cT1-2N0 breast cancer undergoing total mastectomy with positive sentinel lymph nodes.

BACKGROUND AND OBJECTIVES: The ACOSOGZ0011 trial found that overall survival (OS) for patients with 1-2 positive nodes undergoing sentinel lymph node biopsy-alone (SLNB) was noninferior to completion axillary lymph node dissection (ALND), but excluded patients undergoing mastectomy. Our study examined patterns of ALND and its relationship with OS for SLNB-positive patients undergoing mastectomy. METHODS: The National Cancer Database was queried (2010-2017) for patients with cT1-2N0 breast cancer undergoing mastectomy with positive sentinel lymph nodes. Clinical data were compared. RESULTS: Of 20 001 patients, 11 574 (57.9%) underwent SLNB + ALND, and 8427 (42.1%) had SLNB-alone. The SLNB + ALND group had more positive nodes (mean 2.6 vs. 1.3, p < 0.001) and more frequently received nodal radiation (33.4% vs. 28.9%, p < 0.001). Patients diagnosed in later years were less likely to undergo ALND (2010: reference; 2017: odds ratio: 0.29, 95% confidence interval [CI]: 0.25-0.33, p < 0.001). ALND (hazard ratio [HR]: 0.97, 95% CI: 0.89-1.06, p = 0.49) and nodal radiation (HR: 0.92, 95% CI: 0.83-1.02, p = 1.06) were not independently associated with OS. Propensity-score matched 5-year OS was similar (SLNB + ALND: 90.9% vs. SLNB-alone: 90.3%, p = 0.65). CONCLUSION: For patients undergoing mastectomy for cT1-2N0 breast cancer with positive SLNB, SLNB-alone was common and increased over time. Axillary radiation was not routinely delivered in the SLNB-alone group. Completion ALND and nodal radiation were not associated with improved survival.

Access to, Experience with, and Attitudes towards Take Home Naloxone: An Online Survey.

The opioid public health crisis continues to burden individuals, communities, and economies. Public health opinion has emphasized the need for increased access to harm reduction services, but there is a dearth of information on the views and experiences of people who use opioids. Our study aimed to investigate the prevalence of naloxone use, attitudes, and experiences with naloxone among an online community of people who use drugs. We performed a cross-sectional survey looking at experiences with and attitudes towards take-home naloxone. Data is presented descriptively, with analysis of the differences between people who do and do not use opioids using the χ2 and Fisher's exact tests. There were 1,143 respondents, of whom 70% were from the United States. Only 38% of participants who use opioids had received naloxone training, but 56% of these individuals said that they felt comfortable using a naloxone kit. Nearly all respondents (95%) said they would be willing to use naloxone on someone who had overdosed and approximately 90% would want naloxone used on them in case of an overdose. Regarding harm reduction, 24% of respondents said they had access to safe use programs, and 33% said they had access to clean needle exchange programs. A majority of the participants who use opioids were in favor of having naloxone with them when using drugs and believed naloxone should be freely available. This study demonstrates the receptiveness of take-home naloxone and highlights the need for better implementation of naloxone within communities that use opioids.