GSOR10 Presentation Time: 5:45 PM: Trends in Brachytherapy Utilization for the Treatment of Vaginal Cancer in the United States from 2004 to 2020.

According to the American Brachytherapy Society, brachytherapy (BT) is recommended for the treatment of vaginal cancer, particularly cases of bulky and/or recurrent disease. However, previous studies noted a decline in rates during the early 2010s in accordance with similar declines observed in the use of BT for cervical cancer treatment. Recent studies have demonstrated potential recovery in BT utilization in cervical cancer. As such, this study examines more recent trends in BT utilization for vaginal cancer from 2004 to 2020 to assess whether a similar reversal in trends has begun since increased recognition of the importance of BT. This study analyzed data from the National Cancer Database (NCDB) of all patients with FIGO stage I to IVA vaginal cancer treated with pelvic radiation therapy between 2004 and 2020, identifying 6,412 patients. Patients were excluded if they were missing radiation treatment details, or if their survival was less than 5 months. A univariate log binomial regression with robust variance was used to estimate incidence rate ratios (IRRs) of BT utilization overtime and identify potential risk factors associated with receipt. Factors found to be significant in univariate analysis were considered for inclusion in a multivariate model to assess for a relationship with BT use. Additionally, a Cochran Armitage test was conducted to assess for overall trends in BT use. Brachytherapy use increased from 48.0% in 2004 to 67.7% in 2020. In univariate analysis, when compared to 2004, utilization began to significantly increase starting in 2018. Additionally, the test for linear trend was statistically significant (p <0.01). In multivariate model, factors associated with increased brachytherapy use included having non-Medicaid/Medicare government insurance (IRR: 1.28 95% CI: 1.04 - 1.58) when compared to being uninsured, receiving care at an academic/research program (IRR: 1.35 95% CI: 1.16 - 1.57), integrated cancer program (IRR: 1.22 95% CI: 1.04 - 1.42) or other specified type of program (IRR: 1.42 95% CI: 1.14 - 1.78) when compared to community cancer programs, having squamous histology (IRR: 1.08 95% CI: 1.02 - 1.15), and diagnosis after 2018 (IRR: 1.29 95% CI: 1.19 - 1.40). Factors associated with decreased use included American Indian or Alaskan Native race (IRR: 0.57 95% CI: 0.33 - 0.98) when compared to white race, age over 80 (IRR: 0.67 95% CI: 0.61 - 0.77) when compared to age less than 50, and stage II (IRR: 0.94 95% CI: 0.87 - 0.96), III (IRR: 0.69 95% CI: 0.65 - 0.74), or IVA (IRR: 0.41 95% CI: 0.35 - 0.48) disease when compared to stage I. Finally, geographic differences were also observed in BT use. Receiving treating in facilities located in New England (IRR: 0.84 95% CI: 0.74 - 0.95), Middle Atlantic (IRR: 0.87 95% CI: 0.79 - 0.95), South Atlantic (IRR: 0.85 95% CI: 0.78 - 0.93), East North Central (IRR: 0.87 95% CI: 0.80 - 0.96), East South Central (IRR: 0.78 95% CI: 0.70 - 0.87), and West South Central (IRR: 0.70 95% CI: 0.62 - 0.79) census regions were associated with decreased receipt when compared to the West North Central. In patients with FIGO stage I - IVA vaginal cancer treated with pelvic radiation therapy from 2004 to 2020, brachytherapy utilization has significantly increased starting in 2018. Receipt of brachytherapy is also associated with several sociodemographic factors, including insurance status, geographic location, age, and race. These results indicate a recent start of the reversal of previously identified declining use of brachytherapy. However, more work is needed to ensure equitable use across all demographic strata. [ABSTRACT FROM AUTHOR]