Ethnic Disparities in Imaging Utilization at Diagnosis of Non-Small Cell Lung Cancer

Rustain L. Morgan, MD, MS; Sana D. Karam, MD, PhD; Cathy J. Bradley, PhD

Disclosures

J Natl Cancer Inst. 2020;112(12):1204-1212. 

In This Article

Results

Descriptives

The 6-year study period identified 36 469 total patients who met eligibility criteria, of which 28 881 (79.2%) were non-Hispanic white, 3123 (8.6%) were black, and 1907 (5.2%) were Hispanic (Table 1). Approximately 78% of non-Hispanic whites received a PET at diagnosis compared with 63% of blacks and 70% of Hispanics. Numerous other factors were associated with decreased PET use, including older age, unmarried, higher number of comorbidities, and nonteaching facility.

Imaging

Based on odds ratios adjusted for demographic, socioeconomic, and facility characteristics, black patients with squamous cell NSCLC were about one-half as likely to receive a PET (OR = 0.51, 95% CI = 0.44 to 0.60; P < .001) and Hispanic patients were about two-thirds as likely to receive a PET (OR = 0.67, 95% CI = 0.54 to 0.83; P < .001) compared with non-Hispanic whites. In patients with nonsquamous cell NSCLC, the likelihood of receiving a PET was also lower for black (OR = 0.57, 95% CI = 0.51 to 0.64; P < .001) and Hispanic patients (OR = 0.76, 95% CI = 0.67 to 0.88; P < .001). Differences in PET use were evident throughout all stages for both squamous cell carcinoma patients (Figure 2A) and all other histologies (Figure 2B). The PET imaging OR of all histologies for black patients was 0.54 (95% CI = 0.50 to 0.59; P < .001) and 0.72 (95% CI = 0.65 to 0.81; P < .001) for Hispanic patients.

Figure 2.

Positron emission tomography imaging (PET) use by stage and race. A) Use of PET with or without computerized tomography imaging (CT) by stage and race or ethnicity for squamous cell carcinoma. B) Use of PET with or without CT by stage and race or ethnicity for all other histologies of non-small cell lung cancer (NSCLC). Stage based on American Joint Committee on Cancer Staging system. NH = non-Hispanic.

Treatment facility type also predicted PET use. Both NCI centers and teaching hospitals were more likely to use PET (OR = 3.00, 95% CI = 2.17 to 4.16, P < .001; and OR = 1.22, 95% CI = 1.07 to 1.4, P = .004, respectively). Less than 10% of patients received care at an NCI center (7.9% of non-Hispanic whites, 7.4% of blacks, and 8.4% of Hispanics). Teaching hospitals were the most common site of treatment for non-Hispanic whites and blacks, with 47.2% of non-Hispanic whites, 56.7% of blacks, and 41% of Hispanics receiving their treatment from a teaching hospital. The remainder received their care at nonteaching, non-NCI facilities (Figure 3). Additional factors associated with a lower likelihood of PET use included higher census tract poverty level, lower census tract education level, more comorbidity, and whether additional MRI imaging of the brain was also obtained (Table 1).

Figure 3.

Utilization of positron emission tomography imaging (PET) with or without computerized tomography imaging (CT) by race or ethnicity and treatment facility. NH = non-Hispanic; NCI = National Cancer Institute.

Survival

Table 2 reports hazard ratios for CSS. After controlling for demographics, socioeconomic factors, stage, initial imaging, and treatment, black patients are less likely to die (HR = 0.84, 95% CI = 0.75 to 0.94; P = .002). Hispanic patients had a hazard ratio similar to that of white patients and it was not statistically significant. In patients with squamous cell carcinoma histology, PET was associated with a lower probability of death (HR = 0.61, 95% CI = 0.57 to 0.65; P < .001). Likewise, in patients with other histologies, the CSS for patients who had PET was about twice that of patients without a PET (HR = 0.62, 95% CI = 0.60 to 0.65; P < .001) after the first year. Combining all histologies, the probability of survival at 12 months was more than 20% higher in patients imaged with PET than those imaged with CT alone (Figure 4A).

Figure 4.

Survival curves comparing computerized tomography imaging (CT) and positron emission tomography imaging (PET) with or without CT. A) Cancer-specific Kaplan-Meier survival curves comparing CT alone vs PET. P value was generated using the two-sided log-rank test method. B) Overall Kaplan-Meier survival curves comparing CT alone vs PET. P value was generated using the two-sided log-rank test method.

In assessments of OS, 54.8% of all patients survived the first 12 months after diagnosis. In patients with squamous cell carcinoma histology and who had PET imaging with or without CT vs CT alone, those who had a PET had a lower probability of death (HR = 0.63, 95% CI = 0.59 to 0.67; P < .001) (Figure 4A). Findings were similar for patients with other histologies who also had a PET compared with similar patients who did not receive PET imaging (Figure 4B).

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