Analytical performance of the FDA-cleared Parsortix® PC1 system.

Introduction: The Parsortix® PC1 system, Food and Drug Administration (FDA) cleared for use in metastatic breast cancer (MBC) patients, is an epitope-independent microfluidic device for the capture and harvest of circulating tumor cells from whole blood based on cell size and deformability. This report details the analytical characterization of linearity, detection limit, precision, and reproducibility for this device. Methods: System performance was determined using K2-EDTA blood samples collected from self-declared healthy female volunteers (HVs) and MBC patients spiked with prelabeled cultured breast cancer cell lines (SKBR3, MCF7, or Hs578T). Samples were processed on Parsortix® PC1 systems and captured cells were harvested and enumerated. Results: The system captured and harvested live SKBR3, MCF7, and Hs578T cells and fixed SKBR3 cells linearly between 2 and ~100 cells, with average harvest rates of 69%, 73%, 79%, and 90%, respectively. To harvest ≥1 cell ≥95% of the time, the system required 3, 5 or 4 live SKBR3, MCF7 or Hs578T cells, respectively. Average harvest rates from precision studies using 5, 10, and ~50 live cells spiked into blood for each cell line ranged from 63.5% to 76.2%, with repeatability and reproducibility percent coefficient of variation (%CV) estimates ranging from 12.3% to 32.4% and 13.3% to 34.1%, respectively. Average harvest rates using ~20 fixed SKBR3 cells spiked into HV and MBC patient blood samples were 75.0% ± 16.1% (%CV = 22.3%) and 68.4% ± 14.3% (%CV = 21.1%), respectively. Conclusions: These evaluations demonstrate the Parsortix® PC1 system linearly and reproducibly harvests tumor cells from blood over a range of 1 to ~100 cells.

Quantifying the contribution of modifiable risk factors to socio-economic inequities in cancer morbidity and mortality: a nationally representative population-based cohort study.

BACKGROUND: Compared with those with a higher socio-economic position (SEP), individuals with a lower SEP have higher cancer morbidity and mortality. However, the contribution of modifiable risk factors to these inequities is not known. This study aimed to quantify the mediating effects of modifiable risk factors to associations between SEP and cancer morbidity and mortality. METHODS: This study used a prospective observational cohort design. We combined eight cycles of the Canadian Community Health Survey (2000/2001-2011) as baseline data to identify a cohort of adults (≥35 years) without cancer at the time of survey administration (n = 309 800). The cohort was linked to the Discharge Abstract Database and the Canadian Mortality Database for cancer morbidity and mortality ascertainment. Individuals were followed from the date they completed the Canadian Community Health Survey until 31 March 2013. Dates of individual first hospitalizations for cancer and deaths due to cancer were captured during this time period. SEP was operationalized using a latent variable combining measures of education and household income. Self-reported modifiable risk factors, including smoking, excess alcohol consumption, low fruit-and-vegetable intake, physical inactivity and obesity, were considered as potential mediators. Generalized structural equation modelling was used to estimate the mediating effects of modifiable risk factors in associations between low SEP and cancer morbidity and mortality in the total population and stratified by sex. RESULTS: Modifiable risk factors together explained 45.6% of associations between low SEP and overall cancer morbidity and mortality. Smoking was the most important mediator in the total population and for males, accounting for 15.5% and 40.2% of the total effect, respectively. For females, obesity was the most important mediator. CONCLUSIONS: Modifiable risk factors are important mediators of socio-economic inequities in cancer morbidity and mortality. Nevertheless, more than half of the variance in these associations remained unexplained. Midstream interventions that target modifiable risk factors may help to alleviate inequities in cancer risk in the short term. However, ultimately, upstream interventions that target structural determinants of health are needed to reduce overall socio-economic inequities in cancer morbidity and mortality.

A cross-sectional examination of the correlates of current smoking among off-reserve First Nations and Métis adults: Evidence from the 2012 Aboriginal Peoples Survey.

INTRODUCTION: The purpose of this study was to examine the correlates of current smoking among off-reserve First Nations and Métis adults, two Aboriginal Canadian groups that are at higher risk to smoke and more likely to suffer from chronic health conditions relative to their non-Aboriginal counterparts. A particular focus was on culturally specific factors and their associations with current smoking. METHODS: We used data from Statistics Canada's, 2012 Aboriginal Peoples Survey to investigate the correlates of smoking among 12,720 First Nations and Métis adults. Sequential binary logistic regression models were estimated to examine associations between smoking and culturally specific, demographic, geographic, socioeconomic and health-related variables. RESULTS: Overall, 39.4% were current smokers. Multivariate results found that those who had hunted, fished or trapped within the last year were more likely to be smokers. In addition, respondents who were exposed to an Aboriginal language at home or outside the home were more likely to be smokers. Current smoking was significantly associated with being aged 35 to 49 years, living in a small population center, low income, low education, unemployment, being unmarried, low ratings of self-perceived health, heavy drinking and low body mass index. Respondents aged 65 years and older and those living in British Columbia were less likely to smoke. DISCUSSION: The results of this study suggest that it may be useful to consider cultural characteristics, particularly language in efforts to reduce the prevalence of manufactured tobacco use among First Nations and Métis adults. Interventions should also consider demographic, geographic and socioeconomic variables, in addition to co-occurring health-risk behaviors.

The correlates of current smoking among adult Métis: Evidence from the Aboriginal Peoples Survey and Métis Supplement.

OBJECTIVE: To examine the correlates of current smoking among Métis aged 18 years and older, with a particular focus on culturally-specific factors. Cultural factors included spirituality, knowledge of an Aboriginal language, membership in a Métis organization and attendance at Métis cultural events. Demographic, geographic, socio-economic and health-related variables were also considered. METHODS: Data from 6,610 adult Métis aged 18 years and older who responded to the 2006 Aboriginal Peoples Survey and Métis supplement were used to examine the correlates of current smoking using sequential binary logistic regression modelling. RESULTS: Overall, 39.9% of adult Métis respondents in the sample were current smokers. Adult Métis who reported a high level of spirituality were less likely to be current smokers. Those who spoke an Aboriginal language, or lived in a house where an Aboriginal language was spoken, were more likely to be current smokers. Being a member of a Métis organization and attending cultural events were not independently associated with current smoking. Métis with higher household income, greater education, higher self-perceived health, and greater physical activity participation were less likely to be current smokers, whereas those who reported heavy alcohol consumption were more likely to be current smokers. CONCLUSIONS: The results of this study suggest that interventions aimed at reducing smoking among adult Métis might be more successful if they include some connection to spirituality. It is also evident that co-occurring risk behaviours, in addition to demographic and socio-economic factors, are important considerations when developing interventions to reduce smoking among this population.