Superior Prognostic Value of Cumulative Intracranial Tumor Volume Relative to Largest Intracranial Tumor Volume for Stereotactic Radiosurgery-Treated Brain Metastasis Patients

Abstract

BACKGROUND:Two intracranial tumor volume variables have been shown to prognosticate survival of stereotactic-radiosurgery-treated brain metastasis patients: the largest intracranial tumor volume (LITV) and the cumulative intracranial tumor volume (CITV). OBJECTIVE: To determine whether the prognostic value of the Scored Index for Radiosurgery (SIR) model can be improved by replacing one of its components-LITV-with CITV. METHODS:We compared LITV and CITV in terms of their survival prognostication using a series of multivariable models that included known components of the SIR: age, Karnofsky Performance Score, status of extracranial disease, and the number of brain metastases. Models were compared using established statistical measures, including the net reclassification improvement (NRI > 0) and integrated discrimination improvement (IDI). The analysis was performed in 2 independent cohorts, each consisting of ∼3000 patients. RESULTS: In both cohorts, CITV was shown to be independently predictive of patient survival. Replacement of LITV with CITV in the SIR model improved the model's ability to predict 1-yr survival. In the first cohort, the CITV model showed an NRI > 0 improvement of 0.2574 (95% confidence interval [CI] 0.1890-0.3257) and IDI of 0.0088 (95% CI 0.0057-0.0119) relative to the LITV model. In the second cohort, the CITV model showed a NRI > 0 of 0.2604 (95% CI 0.1796-0.3411) and IDI of 0.0051 (95% CI 0.0029-0.0073) relative to the LITV model. CONCLUSION: After accounting for covariates within the SIR model, CITV offers superior prognostic value relative to LITV for stereotactic radiosurgery-treated brain metastasis patients.

Improving the Prognostic Value of Disease-Specific Graded Prognostic Assessment Model for Renal Cell Carcinoma by Incorporation of Cumulative Intracranial Tumor Volume

“…[10] The overall survival patterns of these RCC patient cohorts were comparable in terms of median and 12-month survival (Table 1a). As such, these two cohorts were combined into a single cohort of 360 patients, with the goal of maximizing the statistical power of this “discovery” cohort.…”

“…[7] The scale suggests that survival prognostication for RCC patients with BM is reliant on two clinical variables: Karnofsky’s Performance Score (KPS) and the number of BM. [7] Our previous work suggests that the Cumulative Intracranial Tumor Volume (CITV) of BM, defined as the sum volume of all intracranial metastases at the time of presentation, served as a strong prognostic factor for lung cancer patients afflicted with BM [8–10]. However, since the fundamental premise of dsGPA is that prognostic factors critical for each cancer type differ, it remains unclear whether CITV serve as an important prognostic factor in the context of RCC dsGPA.…”

Operative and peri‐operative considerations in the management of brain metastasis

“…While the use of SRS as a monotherapy has limitations, which include higher rates of salvage therapy, leptomeningeal disease, and distant tumor recurrences compared to WBRT, the overall survival and cost‐effectiveness of SRS alone vs SRS + WBRT favored SRS alone in two recent studies for up to 10 metastases . While one of the theoretical advantages of WBRT is its ability to treat multiple lesions at once, the data suggests that SRS is not limited by the number of lesions, but rather, the combined tumor volume (CTV) of the metastases, with WBRT favored only when the total tumor burden exceeds 5‐7 cm 3 . Indeed, Yamamoto et al showed no difference in treatment efficacy or toxicity in patients treated with SRS for 2‐9 vs >10 BM .…”

Prognostic grading system specifically for elderly patients with brain metastases after stereotactic radiosurgery: a 2-institution study

“…11 Also, Hirshman et al stated that cumulative intracranial tumor volume offers superior prognostic value relative to the largest intracranial tumor volume for SRStreated BM patients. 5 Serizawa et al reported that the post-SRS MST of patients with a cumulative tumor volume of 15 cm 3 or larger was significantly shorter than that of patients with a cumulative tumor volume less than 15 cm 3 . 16 Therefore, the addition of tumor numbers and cumulative tumor volume as scoring factors to the BSBM system is regarded as significantly improving the prognostic value of this index.…”