Disparities in Use of Salvage Whole Brain Radiation Therapy vs. Salvage Stereotactic Radiosurgery After Initial Stereotactic Radiosurgery for Brain Metastases

• Published in: International journal of radiation oncology, biology, physics Vol. 111; no. 3; pp. e580 - e581
• Main Authors: Soni, Y.S., Rich, B.J., Kwon, D., Zhao, W., John, D.L., Seldon, C.S., Benjamin, C., Benveniste, R., Komotar, R.J., Prieto, P., Fuente, M. De La, Azzam, G., Mellon, E.A., Diwanji, T.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.11.2021
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2021.07.1560

Patients undergoing stereotactic radiosurgery (SRS) for brain metastases often relapse and require additional radiation. Due to the paucity of data, the decision to offer salvage re-irradiation with whole brain radiation therapy (WBRT) versus SRS is made on an individual basis. Our objective is to determine the clinical and demographic factors associated with SRS versus WBRT for salvage of first intracranial failure (ICF), i.e., local and/or locoregional failures. We identified a cohort of 374 consecutive patients with brain metastases treated with SRS in the definitive or postoperative setting, at a single institution, from August 2014 to September 2019. Eligible patients received subsequent salvage radiation at our institution with WBRT or SRS at least one month after initial SRS. Clinical and demographic characteristics were retrospectively recorded. Univariate (UVA) and multivariate analyses (MVA) were performed to determine if there was a significant correlation between these factors and the use of salvage SRS versus WBRT. Odds ratios (ORs) and corresponding P-values were estimated from logistic regression model. A survival analysis was also performed to assess the impact of these factors on survival. All tests were two sided and P-value of < 0.05 was used for significance. A total of 110 patients (median age 60, median time to salvage radiation 5.85 months, median follow-up from initial treatment 1.47 years and 0.81 years from salvage treatment) met eligibility criteria for inclusion in this study. 78 patients received SRS and 32 patients received WBRT at the time of first ICF. On UVA the following factors were associated with salvage SRS: having a single new lesion (OR 9.86, P = 0.012), ≥1 stable lesions (OR 5.06, P = 0.001). On UVA the following factors were associated with decreased use of salvage SRS: male gender (OR 0.42, P = 0.044), patient primary language of Spanish (OR = 0.42, P = 0.050), and local progressive lesions (1 lesion OR 0.13, P < 0.001; ≥ 2 lesions, OR 0.10, P = 0.008). On MVA the following factors were associated with decreased use of salvage SRS: male gender (OR = 0.35, P = 0.044) and local progressive lesions (1 lesion OR 0.11, P < 0.001; ≥ 2 lesions, OR 0.11, P = 0.038). Median OS from time of salvage SRS was 1.56 years for the entire cohort. Factors associated with increased survival on MVA included KPS > 70, Stable/absent systemic disease, and receipt of salvage SRS. The strongest factor associated with selection of salvage WBRT vs. SRS for ICF following initial SRS is local progression. There was also found to be a significant disparity in the form of decreased salvage SRS for male patients that remained significant when controlling for other disease and socioeconomic factors. Possible etiologies of this difference could be provider or patient driven but warrant further exploration. In this cohort, salvage SRS was associated with a statistically significant improvement in OS, however, this may also represent a selection bias. Y.S. Soni: None. B.J. Rich: None. D. Kwon: None. W. Zhao: None. D.L. John: None. C.S. Seldon: None. C. Benjamin: None. R. Benveniste: None. R.J. Komotar: None. P. Prieto: None. M. De La Fuente: None. G. Azzam: None. E.A. Mellon: None. T. Diwanji: None.