Racial Differences in Treatments and Toxicity in Non-Small Cell Lung Cancer Patients Treated with Thoracic Radiation Therapy

Background: Racial disparities are of particular concern for lung cancer patients given historical differences in surgery rates for African-American lung cancer patients that resulted in lower overall survival and higher recurrence rates compared with rates in White patients. Objectives: The overall objective of this study was to examine racial differences in thoracic radiation therapy (RT) treatments and toxicities in a large cohort of patients from a multi-institutional consortium database of non-small cell lung cancer (NSCLC) patients. Methods: A large multi-institutional statewide prospectively collected patient-level database of locally advanced (stage II or III) NSCLC patients who received thoracic RT from March 2012 to November 2019 was analyzed to assess the associations between race and treatment and toxicity variables. Race (White or African-American) was defined by patient self-report or if not available then by the electronic medical record system classification. Race categories other than White or African-American comprised a small minority of patients and were excluded from this analysis. Patient-reported toxicity was determined by validated tools including the Functional Assessment of Cancer Therapy-Lung (FACT-L) quality of life instrument. Provider-reported toxicity was determined by the Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Uni-variable and multi-variable regression models were then fitted to assess relationships between primary outcomes by race and indicators of high-quality treatment and secondary analysis of symptoms. Spearman rank correlation coefficients were calculated between provider reported toxicity and similar patient reported outcomes for each race category. Results: A total of 1441 patients from 24 institutions with mean age of 68 years (range 38-94) were evaluated; 226 patients were African-American, of whom 61% were treated at three facilities. Race was not significantly associated with RT treatment approach, use of concurrent chemotherapy, or the dose to the planning target volume (PTV) or organs at risk including the heart and lungs. However, there was increased patient-reported general pain in African-American patients (compared with White patients) at several time points including pre-RT (22% (vs 15%), P=0.02) and at the end of RT (30% (vs 17%), P=0.001). African-American patients were significantly less likely to have provider-reported grade 2+ radiation pneumonitis (odds ratio (OR) 0.36, P=0.03), despite similar levels of patient-reported respiratory toxicities such as cough and shortness of breath and even after controlling for known patient and treatment-related factors. Correlation coefficients between provider- and patient-reported toxicities were generally similar across race categories. Conclusions: In this large multi-institutional observational study, we reassuringly found no evidence of differences in radiation treatment or chemotherapy approaches by race, in contrast to historical differences by race in surgical care that led to worse survival and outcomes in minority race patients. However, we did unexpectedly find that African-American race was associated with lower odds of provider-reported grade 2+ radiation pneumonitis despite similar patient-reported toxicities of shortness of breath and cough. There are several possibilities for this finding including that pneumonitis is a multifactorial diagnosis that relies on clinical as well as radiologic information and clinical information alone may be insufficient. The Spearman correlation analysis also revealed stronger correlations between patient- and provider-reported toxicities in White patients compared with African-American patients, particularly for trouble swallowing/esophagitis. These findings together for pneumonitis and esophagitis discouragingly suggest possible under-recognition of symptoms in black patients. Further investigation is now warranted to better understand how these findings impact the care of racially diverse lung cancer patients