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

Results

Study Population

A total of 8176 patients were identified for study inclusion, of whom 9.9% (n = 811) were Black and 90.1% (n = 7365) were White (Figure 1). A larger proportion of Black patients were female (56.6% vs 50.5%) and younger (median 62 years vs 68 years old) compared with White patients (P < .05) (Table 1). Additionally, Black patients were more likely to have Medicaid insurance (8.4% vs 2.9%) or to be uninsured (7.5% vs 2.3%, P < .001). Median household income and zip code–based educational status were also markedly lower among Black patients (P < .001). Within the study cohort, a larger proportion of Black patients was diagnosed with pathologic stage III CRC (44.4% vs 38.1%, P = .005). No difference in tumor sidedness between White and Black patients was observed (P = .11). Black patients were more likely to be treated at an academic facility (31.2% vs 16.0%) and to travel a shorter distance for care (median 47 vs 63 miles, P < .001). Clinical and tumor characteristics were similar among Black and White patients (Supplementary Table 1, https://academic.oup.com/jnci/article/113/6/770/5999805?login=true#supplementary-data available online).

Figure 1.

Cohort selection for surveillance cohort. CRC = colorectal cancer; NCDB = National Cancer Data Base.

Guideline Concordance

Among patients with colon cancer, rates of adequate lymphadenectomy (removal of at least 12 LN) did not differ by race (Black, 72.2% vs White, 69.6%, P = .06). Among patients with high-risk stage II colon cancer, no difference was observed in rates of adjuvant chemotherapy use (Black, 37.5% vs White, 30.5%, P = .45). However, a greater proportion of Black patients with stage III colon cancer were treated with adjuvant chemotherapy compared with their White counterparts (83.1% vs 76.3%, P = .005). Overall rates of guideline concordant colon cancer care were higher among Black patients compared with White patients (76.9% vs 72.6%, P = .02). Black and White patients with clinical stage II or III or pathologic stage II or III rectal cancer were treated with radiation at similar rates (69.1% vs 66.6%, P = .64) (Figure 2).

Figure 2.

Treatment of primary colon and rectal cancer by race. Colon cancer guideline concordant care (GCC) was defined as removal of at least 12 lymph nodes (LN) and all LN negative (American Joint Committee on Cancer stage I or low-risk stage II); or removal of fewer than 12 LN but the patient received adjuvant chemotherapy (high-risk stage II); or removal of at least 12 LN and 1 or more LN positive and the patient received adjuvant chemotherapy (stage III). Rectal cancer GCC was defined as receipt of neoadjuvant or adjuvant radiation in patients with either clinical stage II or III or pathologic stage II or III disease.

Primary Outcome: Recurrence and OS

Black race was independently associated with increased risk of CRC recurrence and worse OS by adjusted analysis (Figure 3, A and B). By regression analysis adjusting for clinical factors previously demonstrated to be predictive of recurrence, risk of recurrence was also higher in Black patients (hazard ratio [HR] = 1.53, 95% confidence interval [CI] = 1.32 to 1.78). When socioeconomic factors, specifically insurance status, income, and population density of residence, were added to the model, Black race remained associated with risk of recurrence (HR = 1.48, 95% CI = 1.26 to 1.73) (Table 2). Similar findings were observed for OS. Black race was associated with increased risk of death (HR = 1.44, 95% CI = 1.26 to 1.66) compared with White race. This finding also persisted after adjusting for measured socioeconomic factors (HR = 1.37, 95% CI = 1.18 to 1.59) (Table 2). These findings were also confirmed by propensity weighted analysis (data not shown).

Figure 3.

Regression-adjusted recurrence rates and overall survival rates by tumor site and race (N = 8176).

Secondary Outcomes and Sensitivity Analysis

Among those with locoregional or distant recurrent disease, White patients were treated with surgical therapy either alone or in combination with chemotherapy or radiation more often than Black patients (24.0% [n = 288] vs 16.8% [n = 32], P = .04). Accordingly, White patients were treated less often with chemotherapy or chemoradiation alone compared with Black patients (40.9% [n = 490] vs 49.0% [n = 93], P = .04).

Sensitivity analysis was performed to include only the cohort of patients who received GCC for their primary CRC (Supplementary Table 2, available online). This demonstrated a similar increased hazard for recurrence and mortality among Black compared with White patients (HR = 1.51, 95% CI = 1.27 to 1.79; and HR = 1.40, 95% CI = 1.18 to 1.66) (Supplementary Table 3, available online).

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