Disparity of Colon Cancer Outcomes in Rural America: Making the Case to Travel the Extra Mile

Geographic inequities and access to colorectal cancer surgery among rural residents: one size does not fit all!

PURPOSE

Nearly 60 million rural Americans face disparities in cancer surgery access and outcomes within a heterogeneous geographic landscape. This United States population-based study examined regional disparities in access to colorectal cancer (CRC) surgery among rural communities.

METHODS

Hospitalization data for rural patients undergoing CRC resections were abstracted from the 2007 to 2020 National Inpatient Sample. Rural patients were identified using the National Center for Health Statistics urban-rural classifications. Four measures were assessed: (i) elective CRC surgery, (ii) elective rectal cancer surgery, (iii) in-hospital mortality after surgery, and (iv) stoma rates. Logistic regression models were estimated to evaluate between-region differences, adjusting for patient- and hospital-level factors.

RESULTS

Among the 331 004 hospitalizations of rural patients who underwent CRC surgery, elective admission rates were highest in the Midwest (76%; omnibus P <.001). Adjusted odds of elective admission were highest in the Midwest and lowest in the South. There were 61 898 rectal cancer surgery hospitalizations identified, of which hospitalizations in the South had the lowest odds of elective admission (P <.001). Hospitalizations of rural patients in the Northeast compared with all other regions experienced 15% to 33% greater adjusted odds of in-hospital mortality after CRC surgery. Adjusted stoma rates were higher in the West (10.3%) than in the Midwest, and the Northeast had higher odds (29.7%) than the South.

CONCLUSION

Geographic disparities in CRC surgery access among rural residents highlight the heterogeneity of rural America, complicating the challenges of adopting a universal approach to address inequities. Exploring underlying factors of these regional differences, such as variations in provider distribution, hospital resources, and local economic conditions, is essential to guide clinical innovations and policy interventions.

Leveraging Pharmacy Education through a Train-the-Trainer Model to Enhance Breast Cancer Literacy in Rural Communities

Rural versus urban communities experience disproportionate challenges in breast cancer outcomes, with higher breast cancer mortality and later stage disease presentation, despite similar diagnosis rates. These disparities are driven by structural barriers, including rural hospital closures, transportation difficulties, and limited access to oncology specialists. This study evaluated a train-the-trainer program designed to equip PharmD students located at a pharmacy school in a rural county in South Carolina with breast cancer education training, leveraging the pharmacists' position as accessible healthcare professionals in rural communities. Training focused on breast cancer risk factors, prevention, screening, genetics, staging, and treatment options. Effectiveness was measured through pre- and post-workshop confidence surveys and knowledge assessments. Results showed significant improvement in student confidence across educational domains, with average scores increasing from 6.30 to 8.59 (p<0.0001). Understanding of screening guidelines (mean difference: 4.30; p-value: <.0001) and target therapy options showed the greatest improvement (mean difference: 3.65; p-value: <.0001), while knowledge of BRCA gene inheritance showed the smallest change (mean difference: 0.369; p-value: ns), suggesting some pre-existing awareness but limited understanding of its clinical applications. Overall, this pilot program demonstrates how pharmacy education can address healthcare disparities in rural communities. By preparing pharmacists to deliver accurate breast cancer education and to increase rural patient agency, this model creates a sustainable approach to improving health literacy in medically underserved areas. Future research could further expand this model to include diverse healthcare professionals and incorporate long-term impact assessments in community settings.

The intersection of race, ethnicity, and urbanicity on treatment paradigms and clinical outcomes for non-malignant primary tumors of the spine

BACKGROUND

Non-malignant primary tumors of the spine (NMPTS) patients in rural areas face unique barriers that may limit their capacity to receive optimal care. With a lower geographical distribution of neurosurgical specialists and limited healthcare infrastructure, rural NMPTS patients may receive certain treatments at a lower frequency than metropolitan patients. NMPTS We sought to examine the association between residential urbanicity, race-ethnicity, treatment patterns, and survival outcomes for cases diagnosed with NMPTS.

METHODS

Cases of NMPTS diagnosed between 2004 and 2019 were identified from the Central Brain Tumor Registry of the United States (CBTRUS), a combined dataset of CDC's National Program of Cancer Registries (NPCR) and NCI's Surveillance, Epidemiology and End Results (SEER) data. Using multivariable logistic regression, we evaluated the association between urbanicity and treatment (including surgery and radiation), adjusted for age at diagnosis, sex, and race-ethnicity. Patient-level all-cause survival data were obtained from the NPCR Survival Analytical Database (2004-2018).

RESULTS

A total of 38,414 cases were identified, 33,097 of whom lived in metropolitan and 5317 of whom lived in non-metropolitan regions. Nerve sheath tumors and meningiomas were the most common tumor histopathologies across both regions, with no clinically significant difference in other histopathologies (p<0.001). There were statistically significant differences between the frequency and type of surgery received by urbanicity (p<0.001). Overall all-cause survival was significantly lower for NH Blacks residing in non-metropolitan areas when compared to NH Blacks residing in metropolitan areas (p<0.0001).

CONCLUSION

Our data demonstrates significant differences in the incidence of NMPTS across both race-ethnicity and urbanicity. However, a wider analysis of all-cause mortality reveals disparities in health outcomes across both race-ethnicity and urbanicity for Black and Hispanic populations. To address the disparity in health outcomes, policymakers and health providers need to work with local communities in rural areas to improve access to equitable and quality healthcare.

High-risk rural surgical patients and poor access to elective colorectal cancer surgery: insight for multilevel intervention for rural America

BACKGROUND

Colorectal cancer (CRC) is a leading cause of death in rural America. Rural populations are large and heterogeneous, yet patient-related drivers of inequities in CRC access are understudied. This study aimed to identify vulnerable rural populations at lower odds of undergoing elective CRC surgery.

METHODS

Evaluation of the Policy Map and United States Census Bureau identified factors associated with poor surgical access in the most populous states (by total rural population). To assess whether these identified factors were associated with reduced access to elective CRC surgery, the 2007 to 2020 National Inpatient Sample was used to evaluate 69,212 hospitalizations of rural patients undergoing CRC surgery. Rural was defined as counties with a population of <250,000. Multivariable logistic regression models assessed predictors of elective CRC surgery. Patient- and hospital-level factor interactions were specified a priori.

RESULTS

More than 72% of hospitalizations of rural patients were elective. Multivariate regression analysis demonstrated that older age, multimorbidity, Black race, Latino-Hispanic ethnicity, Medicaid insurance, and rural hospitals predicted lower odds of elective CRC surgery. On interaction analyses, high-risk patients were less likely to undergo elective CRC surgery in urban facilities relative to rural.

CONCLUSION

In this large study of rural dwellers, ethnoracial minorities, elders, and Medicaid beneficiaries had profoundly less access to elective CRC surgery, especially when care was received in urban settings. Future studies should focus on exploring actionable social drivers of health in these rural populations. Findings underscore the need for multilevel interventions to enhance rural access to equitable and quality surgical cancer care.

Race/Ethnicity and Social Determinants of Health and Their Impact on Receiving Appropriate Chemotherapy for Colon Cancer

INTRODUCTION

Despite the heightened understanding and improved treatment for colorectal cancer in the United States, social determinants of health (SDH) play a significant role in the colorectal cancer outcomes. We sought to investigate the relationship between SDH and appropriate utilization of adjuvant chemotherapy in stage III colon cancer.

METHODS

For this retrospective study, we utilized data from the National Cancer Data Base (NCDB). Descriptive statistics are reported, including means and 95% confidence intervals for continuous variables and frequency and proportions for categorical variables. Univariate hypothesis testing to identify categorical level factors associated with treatment used Wilcoxon rank sum or Kruskal-Wallis tests, with multivariate analyses performed using regression analysis.

RESULTS

Significant differences were as follows: Metro-non-Hispanic White patients received treatment less frequently (69.7%) when compared to Metro-non-Hispanic Black patients (73.4%) (P < .001). Increasing age was a negative predictor of likelihood to receive with those over 65 years old having an 83% decrease in likelihood to receive chemotherapy when compared to those under 65 (P < .001). Medicaid patients were 47% less likely and Medicare patients were 40% less likely to receive chemotherapy when compared to those with private insurance (P < .001). Rural patients were statistically more likely to receive chemotherapy (OR 1.42, 1.32-2.52, P < .001) as were urban patients, (OR 1.26, 1.20-1.31, P < .001) when compared to patients residing in metro areas.

CONCLUSION

Age, living in a Metro area, and government insurance status at diagnosis are negatively correlated with the likelihood of receiving chemotherapy. Race was not associated with differences in receiving chemotherapy.

Uncommon Sociodemographic Factors Are Associated With Racial Disparities in Length of Stay Following Oncologic Elective Colectomy

INTRODUCTION

Although outcome disparities by race have been identified in colorectal cancer, these patterns are challenging to explain using variables that are commonly available in databases. In a single institution serving a diverse community, length of stay (LOS) varies by race following elective oncologic colectomy. We investigated previously unexplored variables that may explain the relationship between race and LOS following elective resection of colorectal neoplasms.

METHODS

Retrospective, single institution cohort study from January 2015 to December 2020 for adult patients undergoing elective colorectal cancer resections. Baseline demographic variables and intraoperative factors were analyzed for changes in LOS following elective colorectal resection. Additional retrospective chart review was carried out to determine household member composition and distance from home to hospital. Bivariate analysis was conducted to determine which variables should be included in multivariable analyses. All analyses were conducted using SAS Academic.

RESULTS

Most patients (n = 383) were Asian (40%), Black (12%), or Hispanic (26%). Race and LOS were associated with age (P = 0.001 and P < 0.001 for race and LOS, respectively), American Society of Anesthesiologists class (P = 0.004 and P < 0.001), enhanced recovery after surgery protocols (P = 0.006 and P < 0.001), household members (P = 0.009 and P = 0.002), and discharge disposition (P = 0.049 and P < 0.001). In multivariable analysis, household members (P = 0.021) independently remained associated with LOS after controlling for race (P = 0.008) and discharge disposition (P < 0.001).

CONCLUSIONS

Household member composition varies with LOS, suggesting that level of support at home may influence decisions regarding discharge disposition, which lead to differences in LOS.

Survival disparities in rural versus urban patients with pancreatic neuroendocrine tumor: A multi-institutional study from the US neuroendocrine tumor study group

BACKGROUND

Pancreatic Neuroendocrine Tumors (PNETs) are indolent malignancies that often have a prolonged clinical course. This study assesses disparities in outcomes between PNET patients who live in urban (UA) and rural areas (RA).

METHODS

A retrospective cohort study was performed using the US Neuroendocrine Tumor Study Group database. PNET patients with a home zip code recorded were included and categorized as RA or UA according to the Federal Office of Rural Health Policy. Overall survival (OS) was analyzed by Kaplan-Meier method, log-rank test, and logistical regression.

RESULTS

Of the 1176 PNET patients in the database, 1126 (96%) had zip code recorded. While 837 (74%) lived in UA, 289 (26%) lived in RA. RA patients had significantly shorter median OS following primary PNET resection (122 vs 149 months, p ​= ​0.01). After controlling for income, local healthcare access, distance from treatment center, ASA class, BMI, and T/N/M stage, living in a RA remained significantly associated with worse OS (HR 1.60, 95%CI 1.08-2.39, p ​= ​0.02).

CONCLUSION

Rural patients have significantly shorter OS following PNET resection compared to their urban counterparts.

Race/Ethnicity and Social Determinants of Health and Their Impact on the Timely Receipt of Appropriate Operative Treatment of Colon Cancer

INTRODUCTION

Rates of appropriate surgical treatment of colon cancer are historically worse in traditionally marginalized populations. We sought to examine which social determinants of health may be associated with longer time to appropriate operative intervention.

METHODS

The National Cancer Databank was queried for this retrospective study. Adult patients (18 to 90 years of age) diagnosed between 2004 and 2018 with single or primary, stage III colon cancer were included. Patient demographic variables included age at diagnosis, sex, ethnicity (Hispanic or non-Hispanic), comorbidity score, median household income, education status, rural/urban status, treatment facility type and location, and insurance status. Disease characteristics include stage (stage 3), primary site, surgical margins, tumor size, and number of nodes resected. Reported descriptive statistics include means and 95% confidence intervals for continuous variables and frequency and proportions for categorical variables. Univariate and multivariate analyses were performed.

RESULTS

A total of 134,601 individuals diagnosed with stage 3 colon cancer were included. Time to surgery in all cases had a mean of 26.4 ± 19.0 days. Multivariate analysis of time to surgery indicated that receiving surgery at a Community Cancer Program, Charlson-Deyo Score of 0, younger age, and non-Hispanic-White race/ethnicity are associated with decreased time to surgery (P < .001).

CONCLUSION

Patients who receive surgery at a Community Cancer Program, have fewer comorbidities, have lower household income, are younger, and receive surgery within 50 miles of their primary residence are more likely to have timely surgery.

Patient Travel Distance to Neurologist Visits

BACKGROUND AND OBJECTIVES

The density of neurologists within a given geographic region varies greatly across the United States. We aimed to measure patient travel distance and travel time to neurologist visits, across neurologic conditions and subspecialties. Our secondary goal was to identify factors associated with long-distance travel for neurologic care.

METHODS

We performed a cross-sectional analysis using a 2018 Medicare sample of patients with at least 1 outpatient neurologist visit. Long-distance travel was defined as driving distance ≥50 miles 1-way to the visit. Travel time was measured as driving time in minutes. Multilevel generalized linear mixed models with logistic link function, which accounted for clustering of patients within hospital referral region and allowed modeling of region-specific random effects, were used to determine the association of patient and regional characteristics with long-distance travel.

RESULTS

We identified 563,216 Medicare beneficiaries with a neurologist visit in 2018. Of them, 96,213 (17%) traveled long distance for care. The median driving distance and time were 81.3 (interquartile range [IQR]: 59.9-144.2) miles and 90 (IQR: 69-149) minutes for patients with long-distance travel compared with 13.2 (IQR: 6.5-23) miles and 22 (IQR: 14-33) minutes for patients without long-distance travel. Comparing across neurologic conditions, long-distance travel was most common for nervous system cancer care (39.6%), amyotrophic lateral sclerosis [ALS] (32.1%), and MS (22.8%). Many factors were associated with long-distance travel, most notably low neurologist density (first quintile: OR 3.04 [95% CI 2.41-3.83] vs fifth quintile), rural setting (4.89 [4.79-4.99]), long-distance travel to primary care physician visit (3.6 [3.51-3.69]), and visits for ALS and nervous system cancer care (3.41 [3.14-3.69] and 5.27 [4.72-5.89], respectively). Nearly one-third of patients bypassed the nearest neurologist by 20+ miles, and 7.3% of patients crossed state lines for neurologist care.

DISCUSSION

We found that nearly 1 in 5 Medicare beneficiaries who saw a neurologist traveled ≥50 miles 1-way for care, and travel burden was most common for lower-prevalence neurologic conditions that required coordinated multidisciplinary care. Important potentially addressable predictors of long-distance travel were low neurologist density and rural location, suggesting interventions to improve access to care such as telemedicine or neurologic subspecialist support to local neurologists. Future work should evaluate differences in clinical outcomes between patients with long-distance travel and those without.

Association between Rural Residence and Processes of Care in Pancreatic Cancer Treatment

BACKGROUND

Pancreatic adenocarcinoma (PDAC) is an aggressive malignancy associated with poor outcomes. Surgical resection and receipt of multimodal therapy have been shown to improve outcomes in patients with potentially resectable PDAC; however treatment and outcome disparities persist on many fronts. The aim of this study was to analyze the relationship between rural residence and receipt of quality cancer care in patients diagnosed with non-metastatic PDAC.

METHODS

Using the National Cancer Database, patients with non-metastatic pancreatic cancer were identified from 2006-2016. Patients were classified as living in metropolitan, urban, or rural areas. Multivariable logistic regression was used to identify predictors of cancer treatment and survival.

RESULTS

A total of 41,786 patients were identified: 81.6% metropolitan, 16.2% urban, and 2.2% rural. Rural residing patients were less likely to receive curative-intent surgery (p = 0.037) and multimodal therapy (p < 0.001) compared to their metropolitan and urban counterparts. On logistic regression analysis, rural residence was independently associated with decreased surgical resection [OR 0.82; CI 95% 0.69-0.99; p = 0.039] and multimodal therapy [OR 0.70; CI 95% 0.38-0.97; p = 0.047]. Rural residence independently predicted decreased overall survival [OR 1.64; CI 95% 1.45-1.93; p < 0.001] for all patients that were analyzed. In the cohort of patients who underwent surgical resection, rural residence did not independently predict overall survival [OR 0.97; CI 95% 0.85-1.11; p = 0.652].

CONCLUSIONS

Rural residence impacts receipt of optimal cancer care in patients with non-metastatic PDAC but does not predict overall survival in patients who receive curative-intent treatment.

Associations between urbanicity and spinal cord astrocytoma management and outcomes

BACKGROUND

The management of spinal cord astrocytomas (SCAs) remains controversial and may include any combination of surgery, radiation, and chemotherapy. Factors such as urbanicity (metropolitan versus non-metropolitan residence) are shown to be associated with patterns of treatment and clinical outcomes in a variety of cancers, but the role urbanicity plays in SCA treatment remains unknown.

METHODS

The Central Brain Tumor Registry of the United States (CBTRUS) analytic dataset, which combines data from CDC's National Program of Cancer Registries (NPCR) and NCI's Surveillance, Epidemiology, and End Results Programs, was used to identify individuals with SCAs between 2004 and 2019. Individuals' county of residence was classified as metropolitan or non-metropolitan. Multivariable logistic regression models were used to evaluate associations between urbanicity and SCA. Cox proportional hazard models were constructed to assess the effect of urbanicity on survival using the NPCR survival dataset (2004-2018).

RESULTS

1697 metropolitan and 268 non-metropolitan SCA cases were identified. The cohorts did not differ in age or gender composition. The populations had different racial/ethnic compositions, with a higher White non-Hispanic population in the non-metropolitan cohort (86 % vs 66 %, p < 0.001) and a greater Black non-Hispanic population in the metropolitan cohort (14 % vs 9.9 %, p < 0.001). There were no significant differences in likelihood of receiving comprehensive treatment (OR=0.99, 95 % CI [0.56, 1.65], p = >0.9), or survival (hazard ratio [HR]=0.92, p = 0.4) when non-metropolitan and metropolitan cases were compared. In the metropolitan cohort, there were statistically significant differences in SCA treatment patterns when stratified by race/ethnicity (p = 0.002).

CONCLUSIONS

Urbanicity does not significantly impact SCA management or survival. Race/ethnicity may be associated with likelihood of receiving certain SCA treatments in metropolitan communities.

The Intersection of Race and Rurality and its Effect on Colorectal Cancer Survival

INTRODUCTION

Outcomes in colorectal cancer treatment are historically worse in Black people and residents of rural areas. Purported reasons include factors such as systemic racism, poverty, lack of access to care, and social determinants of health. We sought to determine whether outcomes worsened when race and rural residence intersected.

METHODS

The National Cancer Database was queried for individuals with stage II-III colorectal cancer (2004-2018). To examine the intersectionality of race/rurality on outcomes, race (Black/White) and rurality (based on county) were combined into a single variable. Main outcome of interest was 5-year survival. Cox hazard regression analysis was performed to determine variables independently associating with survival. Control variables included age at diagnosis, sex, race, Charlson-Deyo score, insurance status, stage, and facility type.

RESULTS

Of 463 948 patients, 5717 were Black-Rural, 50 742 were Black-Urban, 72 241 were White-Rural, and 33 5271 were White-Urban. Five-year mortality rate was 31.6%. Univariate Kaplan-Meier survival analysis demonstrated race-rurality was associated with overall survival (P < .001), with White-Urban having the greatest mean survival length (47.9 months) and Black-Rural with the lowest (46.7 months). Multivariable analysis found that Black-Rural (1.26, 95% confidence interval [1.20-1.32]), Black-Urban (1.16, [1.16-1.18]), and White-Rural (HR: 1.05; (1.04-1.07) had increased mortality when compared to White-Urban individuals (P < .001).

CONCLUSION

Although White-Rural individuals fared worse than White-Urban, Black individuals fared worst of all, with the poorest outcomes observed in Black individuals in rural areas. This suggests that both Black race and rurality negatively affect survival, and act synergistically to further worsen outcomes.

Association of Rurality, Race and Ethnicity, and Socioeconomic Status With the Surgical Management of Colon Cancer and Postoperative Outcomes Among Medicare Beneficiaries

Importance

Rural patients with colon cancer experience worse outcomes than urban patients, but the extent to which disparities are explained by social determinants is not known.

Objectives

To evaluate the association of rurality with surgical treatment and outcomes of colon cancer and to investigate the intersection of rurality with race and ethnicity and socioeconomic status.

Design, Settings, and Participants

This cohort study included fee-for-service Medicare beneficiaries 65 years or older diagnosed with incident, nonmetastatic colon cancer between April 1, 2016, and September 30, 2018, with follow-up until December 31, 2018. Data were analyzed from August 3, 2020, to April 30, 2021.

Exposures

Rurality of patient's residence, categorized as metropolitan, micropolitan, or small town or rural, using Rural-Urban Commuting Area codes.

Main Outcomes and Measures

Receipt of surgery, emergent surgery, or minimally invasive surgery (MIS); 90-day surgical complications; and 90-day mortality.

Results

Among 57 710 Medicare beneficiaries with incident, nonmetastatic colon cancer, 46.6% were men, 53.4% were women, and the mean (SD) age was 76.6 (7.2) years. In terms of race and ethnicity, 3.7% were Hispanic, 6.4% were non-Hispanic Black (hereinafter Black), 86.1% were non-Hispanic White (hereinafter White), and 3.8% were American Indian or Alaska Native, Asian or Pacific Islander, or unknown race or ethnicity. Patients residing in nonmetropolitan areas were more likely to undergo surgical resection than those residing in metropolitan areas (69.2% vs 63.9%; P < .001). Black race was independently associated with lower hazard of surgical resection (hazard ratio, 0.92 [95% CI, 0.88-0.95]). Race and ethnicity and measures of socioeconomic status did not modify the association of rurality with surgery. Beneficiaries from small town and rural areas had higher odds of undergoing emergent surgery (adjusted odds ratio [OR], 1.32 [95% CI, 1.20-1.44]) but lower odds of undergoing MIS (adjusted OR, 0.75 [95% CI, 0.70-0.80]), with similar findings for patients residing in micropolitan areas. Members of racial and ethnic minority groups who resided in small town and rural settings experienced higher odds of postoperative surgical complications (P = .001 for interaction) and mortality (P = .001 for interaction). Notably, White patients who resided in small town and rural areas experienced lower odds of postoperative mortality than their White metropolitan counterparts (adjusted OR, 0.81 [95% CI, 0.71-0.92]), but Black patients who resided in small town and rural areas had significantly higher odds of postoperative mortality (adjusted OR, 1.86 [95% CI, 1.16-2.97]) than their Black metropolitan counterparts.

Conclusions and Relevance

These findings suggest that Medicare beneficiaries from small town and rural areas were more likely to undergo surgery for nonmetastatic colon cancer than metropolitan beneficiaries but also more likely to undergo emergent surgery and less likely to have MIS. The experiences of rural patients varied by race; rurality was associated with higher postoperative mortality for Black patients but not for other racial and ethnic groups.

Rural-Urban Disparities in Cancer Outcomes: Opportunities for Future Research

Cancer care disparities among rural populations are increasingly documented and may be worsening, likely because of the impact of rurality on access to state-of-the-art cancer prevention, diagnosis, and treatment services, as well as higher rates of risk factors such as smoking and obesity. In 2018, the American Society of Clinical Oncology undertook an initiative to understand and address factors contributing to rural cancer care disparities. A key pillar of this initiative was to identify knowledge gaps and promote the research needed to understand the magnitude of difference in outcomes in rural vs nonrural settings, the drivers of those differences, and interventions to address them. The purpose of this review is to describe continued knowledge gaps and areas of priority research to address them. We conducted a comprehensive literature review by searching the PubMed (Medline), Embase, Web of Science, and Cochrane Library databases for studies published in English between 1971 and 2021 and restricted to primary reports from populations in the United States and abstracted data to synthesize current evidence and identify continued gaps in knowledge. Our review identified continuing gaps in the literature regarding the underlying causes of rural-urban disparities in cancer outcomes. Rapid advances in cancer care will worsen existing disparities in outcomes for rural patients without directed effort to understand and address barriers to high-quality care in these areas. Research should be prioritized to address ongoing knowledge gaps about the drivers of rurality-based disparities and preventative and corrective interventions.

ctDNA MRD Detection and Personalized Oncogenomic Analysis in Oligometastatic Colorectal Cancer From Plasma and Urine

We hypothesized that circulating tumor DNA (ctDNA) molecular residual disease (MRD) analysis without prior mutational knowledge could be performed after neoadjuvant chemotherapy to assess oligometastatic colorectal cancer (CRC) treated surgically with curative intent. We also investigated urine as an alternative analyte for ctDNA MRD detection in this nongenitourinary setting.

PATIENTS AND METHODS

We applied AVENIO targeted next-generation sequencing to plasma, tumor, and urine samples acquired on the day of curative-intent surgery from 24 prospectively enrolled patients with oligometastatic CRC. Age-related clonal hematopoiesis was accounted for by removing variants also present in white blood cells. Plasma and urine ctDNA MRD were correlated with tumor cells detected in the surgical specimen, and adjuvant treatment strategies were proposed based on ctDNA-inferred tumor mutational burden (iTMB) and targetable alterations.

RESULTS

Seventy-one percent of patients were treated with neoadjuvant chemotherapy. Tumor-naive plasma ctDNA analysis detected MRD at a median level of 0.62% with 95% sensitivity and 100% specificity, and 94% and 77% sensitivity when only considering patients treated with neoadjuvant chemotherapy and putative driver mutations, respectively. In urine, ctDNA MRD detection specificity remained high at 100%, but sensitivity decreased to 64% with median levels being 11-fold lower than in plasma (P < .0001). Personalized ctDNA MRD oncogenomic analysis revealed 81% of patients might have been candidates for adjuvant immunotherapy based on high iTMB or targeted therapy based on actionable PIK3CA mutations.

CONCLUSION

Tumor-naive plasma ctDNA analysis can sensitively and specifically detect MRD in patients with oligometastatic CRC after neoadjuvant chemotherapy. Urine-based ctDNA MRD detection is also feasible; however, it is less sensitive than plasma because of significantly lower levels. Oligometastatic patients with detectable MRD may benefit from additional personalized treatment based on ctDNA-derived oncogenomic profiling.

Comparison of survival of stage I-III colon cancer by travel distance and hospital volume

BACKGROUND

Previous studies have demonstrated improved outcomes at high-volume colorectal surgery centers; however, the benefit for patients who live far from such centers has not been assessed relative to local, low-volume facilities.

METHODS

The 2010-2015 National Cancer Database (NCDB) was queried for patients with stage I-III colon adenocarcinoma undergoing treatment at a single center. A 'local, low-volume' cohort was constructed of 12,768 patients in the bottom quartile of travel distance at the bottom quartile of institution surgical volume and a 'travel, high-volume' cohort of 11,349 patients in the top quartile of travel distance at the top quartile of institution surgical volume.

RESULTS

In unadjusted analysis, patients in the travel cohort had improved rates of positive resection margins (3.7% vs. 5.5%, p < 0.001), adequate lymph-node harvests (92% vs. 83.6%, p < 0.001), and 30- (2.2% vs. 3.9%, p < 0.001) and 90-day mortality (3.7% vs. 6.4%, p < 0.001). On multivariable logistic regression analysis adjusting for patient demographic, tumor, and facility characteristics, the cohorts demonstrated equivalent overall survival (HR: 0.972, p = 0.39), with improved secondary outcomes in the 'travel' cohort of adequate lymph-node harvesting (OR: 0.57, p < 0.001), and 30- (OR 0.79, p = 0.019) and 90-day mortality (OR 0.80, p = 0.004).

CONCLUSIONS

For patients with stage I-III colon cancer, traveling to high-volume institutions compared to local, low-volume centers does not convey an overall survival benefit. However, given advantages including 30- and 90-day mortality and adequate lymph-node harvest, nuanced patient recommendations should consider both these differences and the unquantified benefits to local care, including cost, travel time, and support systems.

Association between urbanicity and surgical treatment among patients with primary glioblastoma in the United States

Background

Glioblastoma (GB) is the most common and most lethal primary malignant brain tumor. Extent of surgical resection is one of the most important prognostic factors associated with improved survival. Historically, patients living in nonmetropolitan counties in the United States have limited access to optimal treatment and health care services. The aim of this study is to determine whether there is an association between urbanicity and surgical treatment patterns among US patients with primary GB.

Methods

Cases with histologically confirmed, primary GB diagnosed between 2005 and 2015 were obtained from the Central Brain Tumor Registry of the United States (CBTRUS) in collaboration with the Centers for Disease Control and Prevention, and the National Cancer Institute. Multivariable logistic regression models were constructed to assess the association between urbanicity and receipt of surgical treatment (gross total resection [GTR]/subtotal resection [STR] vs biopsy only/none) and extent of resection (GTR vs STR), adjusted for age at diagnosis, sex, race, US regional division, and primary tumor site.

Results

Patients residing in nonmetropolitan counties were 7% less likely to receive surgical treatment (odds ratio [OR] = 0.93, 95% CI: 0.89-0.96, P < .0001). Among those who received surgical treatment, metropolitan status was not significantly associated with receiving GTR vs STR (OR = 0.99, 95% CI: 0.94-1.04, P = .620).

Conclusions

Among US patients with GB, urbanicity is associated with receipt of surgical treatment, but among patients who receive surgery, urbanicity is not associated with extent of resection. These results point to potential differences in access to health care for those in nonmetropolitan areas that warrant further exploration.