Race, Socioeconomic Factors May Impact Survival Outcome in Limited-Stage Small Cell Lung Cancer

A recent study showed that, among patients with limited-stage small cell lung cancer (LS-SCLC), patients of color had longer overall survival (OS) than White patients, suggesting race is associated with survival in this disease, according to data analysis published in JAMA Network Open.1

Among patients with stage I disease, no significant difference across races was observed (P = .54). The median OS in Hispanic patients was 27.7 months (95% CI, 19.4–not reached [NR]) vs 22.0 months (95% CI, 21.3-22.7 months) in White patients. Among those with stage II disease, Asian patients had a median OS of 20.4 months (95% CI, 15.0-28.0) compared to 17.5 months (95% CI, 14.8–NR) in Hispanic patients. Again, no significant difference was observed across races (P = .70).

However, in patients with stage III disease, survival did differ significantly across the races, with a median OS of 12.7 months (95% CI, 12.6-12.9) in White patients vs 13.6 months (95% CI, 13.2-14.1) in African American patients, 13.4 months (95% CI, 10.3-16.9 months) in Hispanic patients, 13.9 months (95% CI, 12.6-15.2 months) in Asian patients, and 13.5 months (95% CI, 11.3-16.7 months) in Native American patients.

“The findings of this cohort study that race is associated with survival of L-SCLC, because Asian and African American patients had better survival compared with White patients,” Kexun Zhou, MBBS, Division of Hematology and Medical Oncology, of Mayo Clinic, and colleagues, wrote. “In addition, our results confirmed that female sex, higher median annual income (≥63,000), private insurance, diagnosis confirmation by positive cytological analysis, larger increase in number of sampled regional lymph nodes examined, and earlier stage at diagnosis were associated with prolonged survival in L-SCLC.”

Along with clinical characteristics and medical care, data have suggested that economic status, medical insurance, sex, and age were linked with occurrence and cancer outcomes. Race has also been considered to be a factor, mostly due to disparities in access to cancer prevention, early detection, and treatment.2,3 Some studies have attributed higher morbidity in African American patients to socioeconomic factors, and others have indicated that race is not an independent predictor of survival when controlling for confounding variables.4-7

Most of these studies were limited by institutional experiences or statewide databases and mainly focused on non–small cell lung cancer and extensive-stage SCLC (ES-SCLC). Because of this, the validity of race, among other factors, for LS-SCLC is not well understood.

For the study, investigators identified patients who had been diagnosed with LS-SCLC between 2004 and 2014. Participants were put into 5 cohorts based on race/ethnicity, as reported by patients in the National Cancer Database. Additionally, residential region was categorized as urban, metro, and rural, and median annual household income was divided into the following categories: less than $38,000, $38,000 to $47,999, $48,000 to $62,999, and $63,000 or more. Moreover, education level was grouped by the percentage of adults with no high school degree in the residential region (less than 7.0%, 7.0% to 12.9%, 13.0% to 20.9%, and 21.0% or greater). Insurance categories included no insurance, government insurance, and private insurance. Diagnostic confirmation was broken up into either histological or cytological analyses, and facility type was classified as non-academic or research program, and academic or research program.

A total of 72,409 patients were included in the analysis. Among these patients, the median age was 67.0 years (range, 23.0-90.0) and just under 60% (55.6%) were women. Moreover, 74.7% were diagnosed with stage III disease, 14.7% had stage I disease, and 10.6% had stage II disease. Regarding racial groups, 90.4% were White, 7.9% were African American, 1.1% were Asian, 0.3% were Hispanic, and 0.3% were Native American.

African American patients were found to have lower income and education levels compared with White and Asian patients. Moreover, African American patients were the largest racial group in the low-income group of less than $38,000 (stage I, 47.1%; stage II, 47.8%; stage III, 50.8%). The same trend was noted in the lower–education level group. Here, African American patients comprised 35.8% of those with stage I disease, 37.2% of those with stage II disease, and 38.7% of those with stage III disease. More than 90% of patients across all races had some form of medical insurance coverage, and the majority had government insurance.

“Eighty-three percent of patients [59,962 patients] were diagnosed according to positive histological findings, and 74% of patients [53,551 patients] were treated at non-academic or research programs across all races,” the study authors wrote. “The exception to this was noted when patients were analyzed by stage, showing that 65% of Hispanic patients [26 patients] with stage I SCLC were treated at academic or research programs. However, the overall number of Hispanic patients remained low.”

Among those with stage I disease, African Americans were found to have lower rates of undergoing surgery for the primary site. No significant differences among races were noted among those with stage II or III disease regarding tumor and treatment characteristics. No difference in the administration of radiation therapy was observed among racial subgroups for any of the disease stages. Although chemotherapy was given to most patients, the proportion was not significantly different among the racial groups except for those with stage II disease. Here, more Hispanic patients received chemotherapy than White, African American, Asian, or Native American patients.

Multivariable analysis revealed that sex, income, education, insurance type, diagnostic confirmation method, number of sampled regional lymph nodes, and disease stage at diagnosis were significantly associated with survival in patients with LS-SCLC. Moreover, African American patients (HR, 0.92; 95% CI, 0.89-0.95; P < .001) and Asian patients (HR, 0.83; 95% CI, 0.77-0.91; P < .001) appeared to be less likely to die from their disease compared with White patients.

Several other factors were found to be associated with longer survival, including female sex (HR, 0.84; 95% CI, 0.83-0.85; P < .001), a median annual income of $63,000 or higher (HR, 0.94; 95% CI, 0.90-0.98, P < .001), higher education (HR, 0.94; 95% CI, 0.91-0.98, P = .002), and having private insurance (HR, 0.88; 95% CI, 0.81-0.94, P < .001). Patients who had their diagnoses confirmed by positive cytological findings (HR, 0.96; 95% CI, 0.94-0.98; P = .003), had an increase in number of sampled regional lymph nodes (HR, 0.99; 95% CI, 0.98-0.99, P < .001), and who were diagnosed at an earlier disease stage were all linked with longer survival.

“Given that there is a complex interaction among several factors, more studies are warranted to formulate strategies to overcome the disparities that we have highlighted,” the study authors concluded.

References

1. Zhou K, Shi H, Chen R, et al. Association of race, socioeconomic factors, and treatment characteristics with overall survival in patients with limited-stage small cell lung cancer. JAMA Netw Open. 2021;4(1):e2032276. doi:10.1001/jamanetworkopen.2020.32276
2. Ward E, Jemal A, Cokkinides V, et al. Cancer disparities by race/ethnicity and socioeconomic status. CA Cancer J Clin. 2004;54(2):78-93. doi:10.3322/canjclin.54.2.78
3. Bach PB, Schrag D, Brawley OW, et al. Survival of blacks and whites after a cancer diagnosis. JAMA. 2002;287(16):2106-2113. doi:10.1001/jama.287.16.2106
4. Gadgeel SM, Severson RK, Kau Y, et al. Impact of race in lung cancer: analysis of temporal trends from a surveillance, epidemiology, and end results database. Chest. 2001;120(1):55-63. doi:10.1378/chest.120.1.55
5. Tannenbaum SL, Koru-Sengul T, Zhao W, et al. Survival disparities in non-small cell lung cancer by race, ethnicity, and socioeconomic status. Cancer J. 2014;20(4):237-245. doi:10.1097/PPO.0000000000000058
6. Videtic GMM, Reddy CA, Chao ST, et al. Gender, race, and survival: a study in non-small-cell lung cancer brain metastases patients utilizing the radiation therapy oncology group recursive partitioning analysis classification. Int J Radiat Oncol Biol Phys. 2009;75(4):1141-1147. doi:10.1016/j.ijrobp.2008.12.022
7. Kiswas T, Walker P, Podder T, et al. Effect of race and insurance on the outcome of stage I non-small cell lung cancer. Anticancer Res. 2015;35(7):4243-4249.

This article was originally published on OncLive as “Disparities in Race and Socioeconomic Factors Linked with Outcomes in LS-SCLC”