Physicians' Hierarchy of Tumor Biomarkers for Optimizing Chemotherapy in Breast Cancer Care

BACKGROUND

Tumor biomarkers are regularly used to guide breast cancer treatment and clinical trial enrollment. However, there remains a lack of knowledge regarding physicians' perspectives towards biomarkers and their role in treatment optimization, where treatment intensity is reduced to minimize toxicity.

METHODS

Thirty-nine academic and community oncologists participated in semi-structured qualitative interviews, providing perspectives on optimization approaches to chemotherapy treatment. Interviews were audio-recorded, transcribed, and analyzed by 2 independent coders utilizing a constant comparative method in NVivo. Major themes and exemplary quotes were extracted. A framework outlining physicians' conception of biomarkers, and their comfortability with their use in treatment optimization, was developed.

RESULTS

In the hierarchal model of biomarkers, level 1 is comprised of standard-of-care (SoC) biomarkers, defined by a strong level of evidence, alignment with national guidelines, and widespread utilization. Level 2 includes SoC biomarkers used in alternative contexts, in which physicians expressed confidence, yet less certainty, due to a lack of data in certain subgroups. Level 3, or experimental, biomarkers created the most diverse concerns related to quality and quantity of evidence, with several additional modulators.

CONCLUSION

This study demonstrates that physicians conceptualize the use of biomarkers for treatment optimization in successive levels. This hierarchy can be used to guide trialists in the development of novel biomarkers and design of future trials.

Academic and community physician perspectives on breast cancer biomarker use in clinical trials

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Background: Biomarkers are regularly utilized to select treatment within cancer clinical trials. However, there remains a lack of understanding regarding physician perspectives on what data is needed for physicians to comfortably use these markers to escalate or de-escalate chemotherapy. Methods: Semi-structured qualitative interviews with medical oncologists from different academic and community-based cancer centers were conducted to investigate perspectives on the utilization of biomarkers to de-escalate chemotherapy. Key topics explored included: (1) physician preference for biology-based (e.g. genomic profiles) vs. response-based (e.g. complete pathologic response) biomarkers, and (2) importance of personal familiarity with biomarkers. Interviews were audio-recorded and transcribed. Two independent coders analyzed transcripts using a constant comparative method in NVivo to identify major themes. Analysis was stratified by practice-type to elucidate differences between oncologists at academic and community practices. Results: Of the 39 participating physicians, 51% practiced in an academic setting and 49% practiced in a community setting. The majority of physicians (67% overall, 77% community, 59% academic) did not have a preference for biology-based vs. response-based biomarkers, if the data is equally strong and clinical use is appropriate for the clinical context (e.g. patient subtype). Many physicians were reassured by achieving a real-time therapeutic response, with 23% of physicians preferring response-based biomarkers. One physician stated, “I am still more comfortable with a real-time, well-validated biomarker, response marker, than I am with an overall predictive marker for a population”. In contrast, 10% (all academic) preferred biology-based biomarkers. One physician commented “I think the biology is probably more attractive because that potentially allows you to avoid treatment, whereas pathCR they've already had to get treatment to get there”. The majority of academic physicians (55%) felt that strong data was more important than personal familiarity with regards to implementation of novel biomarkers, as noted by one who stated, “As long as there's good data, I don't care.” 15% of community physicians shared a similar view. The majority of community physicians (54%) voiced familiarity to be more important in their comfort with biomarker use as noted by one physician who stated, “I think things I’m already familiar with, I'm more inclined to feel good about”. 18% of academic physicians held a similar perspective. Conclusions: Academic and community physicians’ perspectives regarding use of novel biomarkers overlap, with multiple factors playing a role in how these biomarkers are used in decision-making. Future research is needed to understand the impact of biomarker selection on clinical trial enrollment.

Peeling back the curtain: The impact of patient and provider race on clinical trial enrollment

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Background: Optimization clinical trials testing less intense treatments are becoming more prominent in oncology due to the availability of better prognostic tools and targeted therapies. In addition to previously documented barriers, these trials are likely to face new barriers from engaging racially diverse populations due to the potential of an increased recurrence risk with reducing treatment. However, little is known about the role of race in decision-making for optimization clinical trials amongst physicians and patients. Methods: This qualitative study included a subset analysis on the influence of race in decision-making for participation in trials testing less chemotherapy. This analysis is part of a larger study, which included semi-structured interviews with patients, patient advocates, and physicians assessing barriers and facilitators to trial participation. Interviews were transcribed, and four coders evaluated transcripts for key themes and exemplary quotes using NVivo. Results: 79 participants (24 patients with breast cancer, 16 patient advocates, and 39 physicians) participated; 30% of patients and patient advocates and 26% of physicians were BIPOC (Black, Indigenous, and People of Color). Several key barriers traditionally associated with Black race were noted amongst both patients and physicians, including aggressive biology (e.g. triple negative breast cancer), younger age, socioeconomic challenges, and lack of trust in physicians and clinical trials. One physician noted, “Taking someone who already has a mistrust of medical care and talking to them about a trial of cutting medical care back, it’s challenging.” While some physicians explicitly acknowledged the role of race in decision-making, often linking race to these barriers, the majority of physicians independently highlighted these barriers while denying the explicit impact of race. Black patients noted similar barriers including emphasizing the role of having triple negative breast cancer, being young, the influence of financial strain, and medical mistrust. One Black patient commented, “I was a triple negative, and that kind was more prone to African American women, usually we don’t really survive from it as well as other races do.” Another Black woman commented, “I had a lot of family and friends that were worried that I was going to be a “guinea pig”. In contrast, White patients heavily emphasized the role of trust in their physicians when making decisions. A White woman stated the following, “I would have done whatever they (doctors) told me was the best thing to do.”. Conclusions: Factors associated with Black race can play both an overt and subconscious role in patient and provider decision-making about participation in optimization clinical trials. Multi-level interventions are needed to address these specific barriers to ensure representative participation in clinical trials for all patient populations.

Investigating whole-brain metabolite abnormalities in the chronic stages of moderate or severe traumatic brain injury

BACKGROUND

Evidence suggests that neurometabolic abnormalities can persist after traumatic brain injury (TBI) and drive clinical symptoms such as fatigue and cognitive disruption. Magnetic resonance spectroscopy has been used to investigate metabolite abnormalities following TBI, but few studies have obtained data beyond the subacute stage or over large brain regions.

OBJECTIVE

To measure whole-brain metabolites in chronic stages of TBI.

DESIGN

Observational study.

SETTING

University.

PARTICIPANTS

Eleven men with a moderate or severe TBI more than 12 months prior and 10 age-matched healthy controls completed whole-brain spectroscopic imaging.

MAIN MEASURES

Ratios of N-acetylaspartate (NAA), choline (CHO), and myo-inositol (MI) to creatine (CR) were measured in whole-brain gray and white matter as well as 64 brain regions of interest. Arterial spin labeling (ASL) data were also collected to investigate whether metabolite abnormalities were accompanied by differences in cerebral perfusion.

RESULTS

There were no differences in metabolite ratios within whole-brain gray and white matter regions of interest (ROIs). Linear regression showed lower NAA/CR in the white matter of the left occipital lobe but higher NAA/CR in the gray matter of the left parietal lobe. Metabolite abnormalities were observed in several brain regions in the TBI group including the corpus callosum, putamen, and posterior cingulate. However, none of the findings survived correction for multiple comparison. There were no differences in cerebral blood flow between patients and controls.

CONCLUSION

Higher MI/CR may indicate ongoing gliosis, and it has been suggested that low CHO/CR at chronic time points may indicate cell death or lack of healthy turnover and repair. However, with the small sample size of this study, we caution against the overinterpretation of our results. None of the findings within ROIs survived correction for multiple comparison. Thus, they may be considered possible avenues for future research in this area.