Racial Disparities in Recurrence and Overall Survival in Patients With Locoregional Colorectal Cancer

Rebecca A. Snyder, MD, MPH; Chung-Yuan Hu, MPH, PhD; Syed Nabeel Zafar, MBBS, MPH; Amanda Francescatti, MS; George J. Chang, MD, MS

Disclosures

J Natl Cancer Inst. 2021;113(6):770-777. 

In This Article

Abstract and Introduction

Abstract

Background: The purpose of this study was to determine the association between race and long-term cancer outcomes (recurrence and overall survival) within a population of US patients with locoregional colorectal cancer (CRC).

Methods: A cohort study of primary patient data merged with the National Cancer Database as part of a Commission on Cancer Special Study was performed. The study population was a random sample of patients undergoing surgery for stage I to III CRC between years 2006 and 2007 with 5 years of follow-up. Propensity-weighted multivariable Cox regression was performed with pooled results to yield statistical inferences. Prespecified sensitivity analysis was performed only for patients who received guideline concordant care (GCC) of primary CRC. All statistical tests were 2-sided.

Results: The study population included 8176 patients, 9.9% (n = 811) Black and 90.1% (n = 7365) White. Black patients were more likely to be uninsured or underinsured, have lower household income, and lower educational status (all P < .001). Rates of GCC were higher among Black vs White patients with colon cancer (76.9% vs 72.6%, P = .02), and Black and White patients with rectal cancer were treated with radiation at similar rates (69.1% vs 66.6%, P = .64). Black race was independently associated with increased risk of recurrence (hazard ratio [HR] = 1.48, 95% confidence interval [CI] = 1.26 to 1.73) and mortality (HR = 1.37, 95% CI = 1.18 to 1.59). In sensitivity analysis of only patients who received GCC, observed effects for recurrence (HR = 1.51, 95% CI = 1.27 to 1.79) and overall survival (HR = 1.40, 95% CI = 1.18 to 1.66) persisted.

Conclusions: Despite higher rates of GCC for CRC, Black patients experience a higher risk of recurrence and mortality compared with White patients.

Introduction

Although incidence and mortality rates of colorectal cancer (CRC) are declining in the United States, racial disparities persist. From 2012 to 2016, the incidence of CRC in Black patients was approximately 20% higher than in non-Hispanic White patients (45.7 vs 38.6 per 100 000 population), and the mortality rate was 40% higher (19.0 vs 13.8 per 100 000 population).[1] Black patients present more often with advanced disease but have worse cancer-specific survival for every stage category compared with White patients.[1] However, very little is known about racial differences in CRC recurrence rates following definitive treatment.

Recurrence data are not currently available for analysis within national cancer registries; therefore, recurrence rates among CRC patients have been reported predominately in either single-institution studies or within the context of clinical trials. In 1 compilation of 18 randomized trials of stage III patients treated with adjuvant chemotherapy, the majority (80%) of recurrences occurred within the first 3 years.[2] To date, only 1 study has reported recurrence data using national cancer registry data, which was collected as part of a Commission on Cancer (CoC) special study. In that study, the median time to detection of recurrence was approximately 15 months, and 5-year cumulative recurrence rates were 20% in colon cancer patients and 24% in rectal cancer patients.[3] In the absence of population-based data or multi-institutional studies, however, contemporary data on CRC recurrence outside the context of a clinical trial are sparse, and even less is known about racial differences in recurrence rates within routine clinical practice.

The purpose of this study was to determine the association between race and long-term cancer outcomes (recurrence and overall survival [OS]) within a large population of US patients presenting with locoregional CRC. The hypothesis was that Black patients would experience higher rates of recurrence and worse survival compared with White patients.

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