Distribution of Genomic Testing Resources by Oncology Practice and Rurality: A Nationally Representative Study

Racial and ethnic disparities in genomic testing among lung cancer patients: a systematic review

BACKGROUND

Racial and ethnic disparities in genomic testing could exacerbate disparities in access to precision cancer therapies and survival-particularly in the context of lung cancer where genomic testing has been recommended for the past decade. However, prior studies assessing disparities in genomic testing have yielded mixed results.

METHODS

We conducted a systemic review to examine racial and ethnic disparities in the use of genomic testing among lung cancer patients in the United States. Two comprehensive searches in PubMed, Embase, and Scopus were conducted (September 2022, May 2023). Original studies that assessed rates of genomic testing by race or ethnicity were included. Findings were narratively synthesized by outcome.

RESULTS

The search yielded 2739 unique records, resulting in 18 included studies. All but 1 study were limited to patients diagnosed with non-small cell lung cancer. Diagnosis years ranged from 2007 to 2022. Of the 18 studies, 11 found statistically significant differences in the likelihood of genomic testing by race or ethnicity; in 7 of these studies, testing was lower among Black patients compared with White or Asian patients. However, many studies lacked adjustment for key covariates and included patients with unclear eligibility for testing.

CONCLUSIONS

A majority of studies, though not all, observed racial and ethnic disparities in the use of genomic testing among patients with lung cancer. Heterogeneity of study results throughout a period of changing clinical guidelines suggests that minoritized populations-Black patients in particular-have faced additional barriers to genomic testing, even if not universally observed at all institutions.

Disparities in OncotypeDx Testing and Subsequent Chemotherapy Receipt by Geography and Socioeconomic Status

BACKGROUND

OncotypeDx is a prognostic and predictive genomic assay used in early-stage hormone receptor-positive, HER2- (HR+/HER2-) breast cancer. It is used to inform adjuvant chemotherapy decisions, but not all eligible women receive testing. We aimed to assess variation in testing by demographics and geography, and to determine whether testing was associated with chemotherapy.

METHODS

For 1,615 women in the Carolina Breast Cancer Study with HR+/HER2-, Stage I-II tumors, we estimated prevalence differences (PD) and 95% confidence intervals (CI) for receipt of OncotypeDx genomic testing in association with and sociodemographic characteristics. We assessed associations between testing and chemotherapy receipt overall and by race. Finally, we calculated the proportion of eligible women receiving OncotypeDx by county-level rurality, census tract-level socioeconomic status, and Area Health Education Center regions.

RESULTS

38% (N = 609) of potentially eligible women were tested, with lower testing prevalences in Black (31%; PD, -11%; 95% CI, -16%-6%) and low-income women (24%; PD, -20%; 95% CI, -29% to -11%) relative to non-Black and higher income women. Urban participants were less likely to be tested than rural participants, though this association varied by region. Among women with low genomic risk tumors, tested participants were 29% less likely to receive chemotherapy than untested participants (95% CI, -40% to -17%). Racial differences in chemotherapy were restricted to untested women.

CONCLUSIONS

Both individual and area-level socioeconomics predict likelihood of OncotypeDx testing.

IMPACT

Variable adoption of OncotypeDx by socioeconomics and across geographic settings may contribute to excess chemotherapy among patients with HR+/HER2- cancers. See related In the Spotlight, p. 635.

Area-based disparities in non-small-cell lung cancer survival

BACKGROUND

In the Nordic countries, universal healthcare access has been effective in reducing socioeconomic disparities in non-small-cell lung cancer (NSCLC) management. However, other factors, such as proximity to healthcare facilities, may still affect access to care. This study aimed at investigating the influence of residential area on NSCLC survival.

METHODS

This population-based study utilized hospital records to identify NSCLC patients who underwent their initial treatment at Vaasa Central Hospital between January 1, 2016, and December 31, 2020. Patients were categorized based on their postal codes into urban areas (≤50 km from the hospital) and rural areas (>50 km from the hospital). Survival rates between these two groups were compared using Cox regression analysis.

RESULTS

A total of 321 patients were included in the study. Patients residing in rural areas (n = 104) exhibited poorer 12-month survival rates compared to their urban counterparts (n = 217) (unadjusted Hazard Ratio [HR]: 1.38; 95% Confidence Interval [CI]: 1.01-1.89; p = 0.042). After adjusting for factors such as performance status, frailty, and stage at diagnosis in a multivariate Cox regression model, the adjusted HR increased to 1.47 (95% CI: 1.07-2.01; p = 0.017) for patients living in rural areas compared to those in urban areas.

INTERPRETATION

The study findings indicate that the distance to the hospital is associated with increased lung cancer mortality. This suggests that geographical proximity may play a crucial role in the disparities observed in NSCLC survival rates. Addressing these disparities should involve strategies aimed at improving healthcare accessibility, particularly for patients residing in rural areas, to enhance NSCLC outcomes and reduce mortality.

Genome-matched treatments and patient outcomes in the Maine Cancer Genomics Initiative (MCGI)

Genomic tumor testing (GTT) is an emerging technology aimed at identifying variants in tumors that can be targeted with genomically matched drugs. Due to limited resources, rural patients receiving care in community oncology settings may be less likely to benefit from GTT. We analyzed GTT results and observational clinical outcomes data from patients enrolled in the Maine Cancer Genomics Initiative (MCGI), which provided access to GTTs; clinician educational resources; and genomic tumor boards in community practices in a predominantly rural state. 1603 adult cancer patients completed enrollment; 1258 had at least one potentially actionable variant identified. 206 (16.4%) patients received a total of 240 genome matched treatments, of those treatments, 64% were FDA-approved in the tumor type, 27% FDA-approved in a different tumor type and 9% were given on a clinical trial. Using Inverse Probability of Treatment Weighting to adjust for baseline characteristics, a Cox proportional hazards model demonstrated that patients who received genome matched treatment were 31% less likely to die within 1 year compared to those who did not receive genome matched treatment (HR: 0.69; 95% CI: 0.52-0.90; p-value: 0.006). Overall, GTT through this initiative resulted in levels of genome matched treatment that were similar to other initiatives, however, clinical trials represented a smaller share of treatments than previously reported, and "off-label" treatments represented a greater share. Although this was an observational study, we found evidence for a potential 1-year survival benefit for patients who received genome matched treatments. These findings suggest that when disseminated and implemented with a supportive infrastructure, GTT may benefit cancer patients in rural community oncology settings, with further work remaining on providing genome-matched clinical trials.

Real-world Trends, Rural-urban Differences, and Socioeconomic Disparities in Utilization of Narrow versus Broad Next-generation Sequencing Panels

Advances in genetic technology have led to the increasing use of genomic panels in precision oncology practice, with panels ranging from a couple to hundreds of genes. However, the clinical utilization and utility of oncology genomic panels, especially among vulnerable populations, is unclear. We examined the association of panel size with socioeconomic status and clinical trial matching. We retrospectively identified 9,886 eligible adult subjects in the Mayo Clinic Health System who underwent genomic testing between January 1, 2016 and June 30, 2020. Patient data were retrieved from structured and unstructured data sources of institutional collections, including cancer registries, clinical data warehouses, and clinical notes. Socioeconomic surrogates were approximated using the Area Deprivation Index (ADI) corresponding to primary residence addresses. Logistic regression was performed to analyze relationships between ADI or rural/urban status and (i) use of genomic test by panel size; (ii) clinical trial matching status. Compared with patients from the most affluent areas, patients had a lower odds of receiving a panel test (vs. a single-gene test) if from areas of higher socioeconomic deprivation [OR (95% confidence interval (CI): 0.71 (0.61-0.83), P < 0.01] or a rural area [OR (95% CI): 0.85 (0.76-0.96), P < 0.01]. Patients in areas of higher socioeconomic deprivation were less likely to be matched to clinical trials if receiving medium panel tests [(OR) (95% CI): 0.69 (0.49-0.97), P = 0.03]; however, there was no difference among patients receiving large panel tests (P > 0.05) and rural patients were almost 2x greater odds of being matched if receiving a large panel test [(OR) (95% CI): 1.76 (1.21-2.55), P < 0.01].

SIGNIFICANCE

We identified socioeconomic and rurality disparities in the use of genomic tests and trial matching by panel size, which may have implications for equal access to targeted therapies. The lack of association between large panel tests and clinical trial matching by socioeconomic status, suggests a potential health equity impact, while removing barriers in access to large panels for rural patients may improve access to trials. However, further research is needed.

Molecular diagnostics tailoring personalized cancer therapy-an oncologist's view

Medical oncology is rapidly evolving with the implementation of personalized, targeted therapies. Advances in molecular diagnostics and the biologic understanding of cancer pathophysiology led to the identification of specific genetic alterations as drivers of cancer progression. Further, improvements in drug development enable the direct interference with these pathways, which allow tailoring personalized treatments based on a distinct molecular characterization of tumors. Thereby, we are currently experiencing a paradigm-shift in the treatment of cancers towards cancer-type agnostic, molecularly targeted, personalized therapies. However, this concept has several important hurdles and limitations to overcome to ultimately increase the proportion of patients benefitting from the precision oncology approach. These include the assessment of clinical relevancy of identified alterations, capturing and interpreting levels of heterogeneity based on intra-tumoral or time-dependent molecular evolution, and challenges in the practical implementation of precision oncology in routine clinical care. In the present review, we summarize the current state of cancer-agnostic precision oncology, discuss the concept of molecular tumor boards, and consider current limitations of personalized cancer therapy. Further, we provide an outlook towards potential future developments including the implementation of functionality assessments of identified genetic alterations and the broader use of liquid biopsies in order to obtain more comprehensive and longitudinal genetic information that might guide personalized cancer therapy in the future.

Clinical Network Systems Biology: Traversing the Cancer Multiverse

In recent decades, cancer biology and medicine have ushered in a new age of precision medicine through high-throughput approaches that led to the development of novel targeted therapies and immunotherapies for different cancers. The availability of multifaceted high-throughput omics data has revealed that cancer, beyond its genomic heterogeneity, is a complex system of microenvironments, sub-clonal tumor populations, and a variety of other cell types that impinge on the genetic and non-genetic mechanisms underlying the disease. Thus, a systems approach to cancer biology has become instrumental in identifying the key components of tumor initiation, progression, and the eventual emergence of drug resistance. Through the union of clinical medicine and basic sciences, there has been a revolution in the development and approval of cancer therapeutic drug options including tyrosine kinase inhibitors, antibody-drug conjugates, and immunotherapy. This 'Team Medicine' approach within the cancer systems biology framework can be further improved upon through the development of high-throughput clinical trial models that utilize machine learning models, rapid sample processing to grow patient tumor cell cultures, test multiple therapeutic options and assign appropriate therapy to individual patients quickly and efficiently. The integration of systems biology into the clinical network would allow for rapid advances in personalized medicine that are often hindered by a lack of drug development and drug testing.

The Maine Cancer Genomics Initiative: Implementing a Community Cancer Genomics Program Across an Entire Rural State

PURPOSE

The Maine Cancer Genomics Initiative (MCGI) aimed to overcome patient- and provider-level barriers to using genomic tumor testing (GTT) in rural practices by providing genomic tumor boards (GTBs), clinician education, and access to comprehensive large-panel next-generation sequencing to all patients with cancer in Maine. This paper describes the successful implementation of the initiative and three key services made operative between 2016 and 2020.

METHODS

A community-inclusive, hub-and-spoke approach was taken to implement the three program components: (1) a centralized GTB program; (2) a modular online education program, designed using an iterative approach with broad clinical stakeholders; and (3) GTT free of charge to clinicians and patients. Implementation timelines, participation metrics, and survey data were used to describe the rollout.

RESULTS

The MCGI was launched over an 18-month period at all 19 oncology practices in the State. Seventy-nine physicians (66 medical oncologists, 5 gynecologic oncologists, 1 neuro-oncologist, and 7 pediatric oncologists) enrolled on the study, representing 100% of all practicing oncologists in Maine. Between July 2017 and September 2020, 1610 patients were enrolled. A total of 515 cases were discussed by 47 (73%) clinicians in 196 GTBs. Clinicians who participated in the GTBs enrolled significantly more patients on the study, stayed in Maine, and reported less time spent in clinical patient care.

CONCLUSION

The MCGI was able to engage geographically and culturally disparate cancer care practices in a precision oncology program using a hub-and-spoke model. By facilitating access to GTT, structured education, and GTBs, we narrowed the gap in the implementation of precision oncology in one of the most rural states in the country.

Hospital Rurality and Gene Expression Profiling for Early-Stage Breast Cancer among Iowa Residents (2010-2018)

Objective

Given the challenges rural cancer patients face in accessing cancer care as well as the slower diffusion and adoption of new medical technologies among rural providers, the aim of our study was to examine trends in gene expression profiling (GEP) testing and evaluate the association between hospital rurality and receipt of GEP testing.

Methods

Data from the Iowa Cancer Registry (ICR) were used to identify women with newly diagnosed, histologically confirmed breast cancer from 2010 through 2018 who met eligibility criteria for GEP testing. Patients were allocated to the hospitals where their most definitive surgical treatment was received, and Rural-Urban Commuting Area codes were used to categorize hospitals into urban (N = 43), large rural (N = 16), and small rural (N = 48). Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression to evaluate the association between hospital rurality and GEP test use, adjusting for demographic and clinical characteristics. The association between test result and treatment received was assessed among patients who received Oncotype DX (ODX) testing.

Results

Of 6,726 patients eligible for GEP test use, 46% (N = 3,069) underwent testing with 95% receiving ODX. While overall GEP testing rates increased over time from 42% between 2010 and 2012 to 51% between 2016 and 2018 (P _trend < 0.0001), use continued to be the lowest among patients treated at hospitals in small rural areas. The odds of GEP testing remained significantly lower among patients treated at hospitals located in small rural areas (aOR 0.55; 95% CI 0.43-0.71), after adjusting for demographic and clinical characteristics. ODX recurrence scores were highly correlated with chemotherapy use across all strata of hospital rurality.

Conclusions

GEP testing continues to be underutilized, especially among those treated at small rural hospitals. Targeted interventions aimed at increasing rates of GEP testing to ensure the appropriate use of adjuvant chemotherapy may improve health outcomes and lower treatment-related costs.

"Doing Good" in U.S. Cancer Genomics? Valuation practices across the boundaries of research and care in rural community oncology

Genomic Tumour Testing (GTT) is an emerging site of "experimental care" in oncology [Cambrosio, Alberto, Peter Keating, Etienne Vignola-Gagné, Sylvain Besle, and Pascale Bourret. 2018a. "Extending Experimentation: Oncology's Fading Boundary Bbetween Research and Care." New Genetics and Society 37 (3): 207-226. doi: 10.1080/14636778.2018.1487281]. Few efforts to implement GTT have reached community oncology practices or patients living in rural communities within the US. Drawing on interdisciplinary research on a state-wide cancer genomics initiative in the rural US state of Maine, this paper explores the valuation practices within community oncologist and cancer stakeholders accounts of "doing good" within genomic science and care. We contribute to STS literatures on the bio-economy by highlighting the affective dimensions of strategies for managing economic and non-economic values. Clinician and stakeholders negotiated de-economizing and capitalizing modes of doing good as they built local genomic platforms "for Maine." These situated modes of doing good and feeling good via cancer genomics shaped how they navigated the ethical ambiguities of US biomedical markets across the boundaries of research and care.

Impact of a Clinical Genomics Program on Trial Accrual for Targeted Treatments: Practical Approach Overcoming Barriers to Accrual for Underserved Patients

PURPOSE

Clinical trials of novel and targeted agents increasingly require biomarkers for eligibility. Precision oncology continues to evolve, but challenges hamper broad use of molecular profiling (MP) that could increase the number of patients benefiting from targeted therapy. We implemented an integrated clinical genomics program (CGP), including a virtual Molecular Tumor Board (MTB), and examined its impact on MP use and impact on clinical trial accrual in a multisite regional-based cancer system with an emphasis on effects for isolated clinicians.

METHODS

We assessed MP and MTB use from 2010 to 2020 by practice location, physician experience, and patient characteristics. Use of MTB-recommended treatments was assessed. Clinical trial enrollment was evaluated for patients with MP versus MP and MTB review.

RESULTS

After CGP implementation, the number of physicians using MP and the number of MP tests increased ≥ 10-fold. The proportion of Hispanic patients with MP was the same as that in the system (both 2%) with marginal differences observed in the proportion of African Americans tested compared with the system population (16% v 19%). Physicians followed MTB treatment recommendations in 74% of cases. Rapid clinical decline was the most common reason why physicians did not follow MTB recommendations. Clinical trial accrual was 15% (669 of 4,459) for patients with MP alone and 28% (94 of 334) with both MP and MTB review. Clinical trial availability and patient out-of-pocket costs affected MP use.

CONCLUSION

Integrating CGP into clinical workflow with decision support tools, trial matching, and management of patient costs led to increased use of MP by physicians with all levels of experience, enhanced clinical trial accrual, and has the potential to reduce disparities in MP.

A systematic review of geographical inequities for accessing clinical genomic and genetic services for non-cancer related rare disease

Place plays a significant role in our health. As genetic/genomic services evolve and are increasingly seen as mainstream, especially within the field of rare disease, it is important to ensure that where one lives does not impede access to genetic/genomic services. Our aim was to identify barriers and enablers of geographical equity in accessing clinical genomic or genetic services. We undertook a systematic review searching for articles relating to geographical access to genetic/genomic services for rare disease. Searching the databases Medline, EMBASE and PubMed returned 1803 papers. Screening led to the inclusion of 20 articles for data extraction. Using inductive thematic analysis, we identified four themes (i) Current service model design, (ii) Logistical issues facing clinicians and communities, (iii) Workforce capacity and capability and iv) Rural culture and consumer beliefs. Several themes were common to both rural and urban communities. However, many themes were exacerbated for rural populations due to a lack of clinician access to/relationships with genetic specialist staff, the need to provide more generalist services and a lack of genetic/genomic knowledge and skill. Additional barriers included long standing systemic service designs that are not fit for purpose due to historically ad hoc approaches to delivery of care. There were calls for needs assessments to clarify community needs. Enablers of geographically equitable care included the uptake of new innovative models of care and a call to raise both community and clinician knowledge and awareness to demystify the clinical offer from genetics/genomics services.