Objectives
To test whether the presence of patient- and imaging-level characteristics: 1) are associated with clinically meaningful changes in mobility among late stage cancer patients with metastatic brain involvement; and 2) can predict their risk of near-term functional decline.
Design
Prospective nested cohort study
Setting
Quaternary academic medical center
Participants
The study population consisted of a nested cohort of the 66 patients with imaging confirmed brain metastases among a larger cohort of 311 patients with late stage lung cancer.
Interventions
Not applicable
Main Outcomes
Functional evaluations with the Activity Measure for Post-Acute Care Computer Adaptive Test (AM-PAC-CAT) and symptom intensity ratings were collected at monthly intervals for up to 2 years.
Results
In exploratory univariate models, whole brain radiation therapy (WBRT) and imaging findings of cerebellar or brain stem involvement were associated with large AM-PAC-CAT declines in mobility (−4.55, SE 1.12; −2.87, SE 1.0; and −3.14, SE 1.47, respectively). Also in univariate models, participants with new neurological signs or symptoms at imaging (−2.48, SE 0.99), new brain metastases (−2.14, SE 0.99), or new and expanding metastases (−2.64, SE 1.14) declined significantly. Multivariate exploratory mixed logistic models including WBRT, cerebellar/brainstem location, presence of new and expanding metastases, and worst pain intensity had excellent predictive capabilities for AM-PAC-CAT score declines of 7.5 and 10 points, C statistics ≥0.8.
Conclusions
Among patients with lung cancer and brain metastases, a cerebellar/brainstem location, new and expanding metastases, and treatment with WBRT may predict severe, near-term mobility losses and indicate a need to consider rehabilitation services.