Patterns of care and brachytherapy boost utilization for vaginal cancer in the United States

Abstract Purpose Vaginal cancer is an uncommon malignancy that is usually treated with definitive radiation therapy. Following external beam radiation therapy (EBRT), a brachytherapy boost is delivered to achieve a total dose of 70-85 Gy. We sought to determine the trends of brachytherapy boost utilization in the treatment of vaginal cancer and to identify the factors associated with its utilization. Methods and materials Using the National Cancer Data Base (NCDB), we identified 1530 patients with vaginal cancer from 2004 to 2011 who were treated with radiation therapy and had a recorded boost modality. The following additional variables were identified: age, year of diagnosis, Charlson/Deyo comorbidity score, stage, histology, race, brachytherapy dose rate, brachytherapy applicator technique, treatment facility volume, and utilization of chemotherapy. Multivariable logistic regression analysis was performed to identify factors independently associated with brachytherapy boost. Results Seventy-seven percent of the 1530 women received brachytherapy boost and 23% received EBRT boost. The rate of brachytherapy boost utilization decreased from 87.7% in 2004 to 68.6% in 2011 ( P P = .02). Multivariate analysis revealed that high facility volume was associated with increased odds of brachytherapy boost (odds ratio [OR], 2.3; range, 1.5-3.4). Higher stage and advanced age were associated with decreased odds of brachytherapy boost (OR, 0.2; range, 0.1-0.3 and OR, 0.5; range, 0.3-0.8). Utilization of chemotherapy, histology, race, and comorbidity index were not significantly associated with brachytherapy boost utilization. Conclusions Using the NCDB, we identified a concerning decline in the utilization of brachytherapy boost for those with vaginal cancer and a corresponding increase in IMRT boost technique. The strongest factor predicting for brachytherapy boost utilization is treatment at a high volume facility.