Association of Insulin Resistance and Higher Oncotype DX™ Recurrence Score

Socioecologic Factors and Racial Differences in Breast Cancer Multigene Prognostic Scores in US Women

Importance

Disproportionately aggressive tumor biology among non-Hispanic Black women with early-stage, estrogen receptor (ER)-positive breast cancer contributes to racial disparities in breast cancer mortality. It is unclear whether socioecologic factors underlie racial differences in breast tumor biology.

Objective

To examine individual-level (insurance status) and contextual (area-level socioeconomic position and rural or urban residence) factors as possible mediators of racial and ethnic differences in the prevalence of ER-positive breast tumors with aggressive biology, as indicated by a high-risk gene expression profile.

Design, Setting, and Participants

This retrospective cohort study included women 18 years or older diagnosed with stage I to II, ER-positive breast cancer between January 1, 2007, and December 31, 2015. All data analyses were conducted between December 2022 and April 2023.

Main Outcomes and Measures

The primary outcome was the likelihood of a high-risk recurrence score (RS) (≥26) on the Oncotype DX 21-gene breast tumor prognostic genomic biomarker.

Results

Among 69 139 women (mean [SD] age, 57.7 [10.5] years; 6310 Hispanic [9.1%], 274 non-Hispanic American Indian and Alaskan Native [0.4%], 6017 non-Hispanic Asian and Pacific Islander [8.7%], 5380 non-Hispanic Black [7.8%], and 51 158 non-Hispanic White [74.0%]) included in our analysis, non-Hispanic Black (odds ratio [OR], 1.33; 95% CI, 1.23-1.43) and non-Hispanic American Indian and Alaska Native women (OR, 1.38; 95% CI, 1.01-1.86) had greater likelihood of a high-risk RS compared with non-Hispanic White women. There were no significant differences among other racial and ethnic groups. Compared with non-Hispanic White patients, there were greater odds of a high-risk RS for non-Hispanic Black women residing in urban areas (OR, 1.35; 95% CI, 1.24-1.46), but not among rural residents (OR, 1.05; 95% CI, 0.77-1.41). Mediation analysis demonstrated that lack of insurance, county-level disadvantage, and urban vs rural residence partially explained the greater odds of a high-risk RS among non-Hispanic Black women (proportion mediated, 17%; P < .001).

Conclusions and Relevance

The findings of this cohort study suggest that the consequences of structural racism extend beyond inequities in health care to drive disparities in breast cancer outcome. Additional research is needed with more comprehensive social and environmental measures to better understand the influence of social determinants on aggressive ER-positive tumor biology among racial and ethnic minoritized women from disadvantaged and historically marginalized communities.

Association between insulin resistance and cardiac remodeling in HER2-positive breast cancer patients: a real-world study

BACKGROUND

Insulin resistance is an overlapping risk factor for both heart and breast cancer, while its interaction with cardiotoxicity in breast cancer (BC) patients is not clear. This study investigated the impact of insulin resistance on cardiac remodeling in patients with human epidermal growth factor receptor 2 (HER2)-positive BC during and after trastuzumab therapy in real-world clinical practice.

METHODS

HER2-positive BC patients who received trastuzumab treatment between December 2012 and December 2017 were reviewed and 441 patients with baseline metabolic indices and serial echocardiographic measurements (baseline, 6, 12, and 18 months) after trastuzumab therapy initiation were included. Repeated measurement analysis of variance was used to evaluate temporal trends in multiparameter echocardiography. Linear mixed model was applied to further evaluate the role of insulin resistance in forementioned changes. Correlation of homeostasis model assessment-estimated insulin resistance (HOMA-IR) and triglyceride-glucose index (TyG) levels to changes in echocardiography parameters was explored.

RESULTS

Of 441 patients (mean age 54 ± 10 [SD] years), 61.8% received anthracycline-based chemotherapy, 33.5% received left-sided radiotherapy, 46% received endocrine therapy. No symptomatic cardiac dysfunction was observed over the therapy course. A total of 19 (4.3%) participants experienced asymptomatic cancer therapy-related cardiac dysfunction (CTRCD), and the peak onset time was 12 months after the initiation of trastuzumab. Albeit relatively low CTRCD incidence, cardiac geometry remodeling, especially left atrial (LA) dilation over therapy was notable and was more severe in high HOMA-IR and TyG level groups (P < 0.01). Noteworthy, a partial reversibility of cardiac remodeling was observed with treatment cessation. Additionally, HOMA-IR level positively correlated to changes in LA diameter from baseline to 12 months (r = 0.178, P = 0.003). No significant association (all P > 0.10) was detected between HOMA-IR or TyG level and dynamic left ventricular parameter evaluation. Multivariate linear regression analysis demonstrated that higher HOMA-IR level was an independent determinant for LA enlargement in BC patients during anti-HER2 targeted therapy course after adjusting for confounding risk factors (P = 0.006).

CONCLUSION

Insulin resistance was associated with left atrial adverse remodeling (LAAR) in HER2-positive BC patients that received standard trastuzumab therapy, indicating that insulin resistance could be a supplementation to baseline cardiovascular risk stratification proforma for HER2-targeted antitumor therapies.

Longitudinal changes in fasting plasma glucose are associated with risk of cancer mortality: A Chinese cohort study

BACKGROUND

Numerous studies have suggested that fasting plasma glucose (FPG) was associated with the risk of mortality. However, relationship on longitudinal changes of FPG with the risk of mortality remained inconsistent.

METHODS

We examined the association of FPG at baseline and its longitudinal changes with risk of mortality based on a cohort study in Yinzhou, China, during 2010-2018. Cox regression models and competing risk models were separately used to examine the association of FPG levels and long-term fluctuation with risk of total and cause-specific mortality.

RESULTS

Subjects who had an impaired fasting glucose or diabetes suffered a higher risk of total mortality than subjects who had a normal fasting glucose (HRs and 95% CIs: 1.17 [1.01-1.35], 1.30 [1.10-1.53], respectively). The HR for total mortality was 1.54 (95% CI: 1.29-1.84) and for cancer mortality was 1.41 (95% CI: 1.04-1.92) in the highest quartile of coefficient of variation of FPG. Trajectory analysis indicated that subjects with a significantly changed FPG suffered a higher risk of total mortality.

CONCLUSION

According to this cohort study, we found that long-term fluctuation of FPG was significantly associated with the risk of total and cancer mortality. Our findings suggest that long-term fluctuation of FPG could be used as an efficient indicator for predicting the subsequent risk of mortality.