Disparities in Receipt of Radiotherapy and Survival By Age, Sex and Ethnicity Among Patients with Stage I Follicular Lymphoma

Background: Radiotherapy (RT) is a first line treatment option for stage I follicular lymphoma. In this population-based study, we evaluated disparities in receipt of radiotherapy and survival among patients with stage I follicular lymphoma.

Methods: Adult patients (age ≥18 years) with stage I follicular lymphoma, as the first primary cancer, diagnosed between 1992 and 2007 were identified using Surveillance, Epidemiology and End Results (SEER) 18 database. Study population was divided into various groups based on age (<60 years and ≥60 years), sex, ethnicity (Caucasians, African Americans and Others) and marital status (married, single and separated/divorced/widowed). Binomial logistic regression was used to analyze factors associated with receipt of RT. SEER*Stat was used to compute 5 year RS for various groups and compared using Z score. Cox proportional hazard model was used to compare factors associated with 5 year RS.

Results: Of the total 7328 patients (median age: 63 years), 2675 (36.5%) received RT. African Americans were less likely to receive RT compared to Caucasians (adjusted odds ratio [OR] of 0.602;P <0.001). Older patients (≥60yrs) were less likely to receive RT compared to younger patients (adjusted OR of 0.636; P<0.001). Single and S/D/W were less likely to receive RT compared to married (adjusted OR of 0.835 and 0.865 with P of 0.029 and 0.029 respectively). Recent years of diagnosis was independent predictor of omission of RT (adjusted OR for one year increase is 0.975, P <0.001). 5 years RS was significantly better in patients receiving RT (97%+0.7% vs. 88.4%+0.7%, P <0.0002). In multivariate analysis, male sex, age <60years , Caucasian race and married marital status were found to be independent predictor of better RS among patients receiving RT (P <0.000001).

Conclusion: Among patients with stage I follicular lymphoma, receipt of RT is associated with superior survival. Patients belonging to AA and Others race, old age group, single and S/D/W as marital status and recent years of diagnosis were independent predictors for omission of RT. 5 year RS among the patients receiving RT was significantly better for male, younger age, Caucasians and married patients.