Background

Combination therapy with 3 cycles of chemotherapy followed by involved field radiotherapy has been a standard of care for treatment of localized diffuse large B-cell lymphoma (Miller TP NEJM 1998). This population based study evaluated ethnic disparities in receipt of radiotherapy (RT) and its effect on survival in patients with localized diffuse large B cell lymphoma (DLBCL) in the United States.

Methods

The Surveillance, Epidemiology, and End Results database was reviewed to identify patients with stage I DLBCL diagnosed between 1998 and 2008. We used unadjusted and adjusted odds ratio (OR) to analyze association of receipt of radiotherapy with age (<60 and 60+ years), sex and ethnicity (White, Black and Others). We calculated relative survival rates for different cohorts using SEER*Stat software. We used cox’s proportional hazard model to investigate the impact of age, sex and ethnicity on survival rates.

Results

A total of 11763 patients with localized DLBCL as the only primary malignancy were included in the study. Of the cohort, 38.2% received radiotherapy. Receipt of radiotherapy varied significantly by patient ethnicity - whites were more likely to receive RT compared to blacks and others. Similarly, age <60 years and females were more likely to receive radiotherapy compared with older patients and males (Table – 1).

Table 1

Disparities in the Use of Radiotherapy in Localized DLBCL

ParameterOR95% CIP value
Adjusted    
Age (<60 vs 60+ years) 0.665 0.612-0.722 0.000 
Sex (Male vs Female) 1.158 1.070-1.253 0.000 
Ethnicity    
 White vs Black 0.743 0.636 - 0.869 0.000 
 White vs Others 0.810 0.733 - 0.895 0.011 
Unadjusted    
Age (<60 vs 60+ years) 0.714 0.662 - 0.770 0.000 
Sex (Male vs Female) 1.066 0.989- 1.149 0.097 
Ethnicity    
 White vs Black 0.768 0.659 - 0.895 0.001 
 White vs Others 1.224 1.071 - 1.399 0.003 
ParameterOR95% CIP value
Adjusted    
Age (<60 vs 60+ years) 0.665 0.612-0.722 0.000 
Sex (Male vs Female) 1.158 1.070-1.253 0.000 
Ethnicity    
 White vs Black 0.743 0.636 - 0.869 0.000 
 White vs Others 0.810 0.733 - 0.895 0.011 
Unadjusted    
Age (<60 vs 60+ years) 0.714 0.662 - 0.770 0.000 
Sex (Male vs Female) 1.066 0.989- 1.149 0.097 
Ethnicity    
 White vs Black 0.768 0.659 - 0.895 0.001 
 White vs Others 1.224 1.071 - 1.399 0.003 
*

OR indicates odds ratio and 95% CI indicates 95% Confidence Interval

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The 1- and 5- year relative survival rates for patients receiving RT were higher compared to those who did not receive RT: 88.3±0.5% vs 73.4±0.6%, p-value <0.0001 at 1-year and 77.8±0.8% vs 62.5±0.7%, p-value <0.0001 at 5-years. Among patients who received RT, 1- and 5- year relative survival rates were significantly higher in whites compared to black or other- race patients.

Conclusions

This population based study showed that only 38.2% of patients with localized DLBCL received radiotherapy. White patients were more likely to receive RT compared to blacks and others. Survival rates are significantly higher for patients who received RT.

Disclosures:

No relevant conflicts of interest to declare.

Topics:
diffuse large b-cell lymphoma, ethnic group, health disparity, radiation therapy, cancer, chemotherapy regimen, combined modality therapy, proportional hazards models, ecological study, older adult

Author notes

*

Asterisk with author names denotes non-ASH members.

© 2013 by The American Society of Hematology
2013
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