SADA-21 EXTENT OF RESECTION REMAINS A KEY DETERMINANT OF ONCOLOGIC OUTCOMES IN MINIMALLY INVASIVE TUBULAR RETRACTOR-BASED RESECTION OF BRAIN METASTASES
Michelle Miller, Gabrielle Dituri, Smruti Mahapatra, Shuhei Shiino, Zaynab Sidi Mohamed, Joseph Lockwood, Joseph Keen, Marcus WareAbstract
Background
Minimally invasive tubular retractor systems are increasingly used for resection of brain metastases, but oncologic efficacy remains poorly defined. This technique typically requires piecemeal rather than en bloc resection, which has been associated with increased local recurrence (LR) and leptomeningeal disease (LMD) in studies of non-minimally invasive techniques. We evaluated perioperative and oncologic outcomes after tubular retractor-based resection.
Methods
We retrospectively analyzed adults undergoing resection of previously untreated intra-axial brain metastases using a tubular retractor system at a single institution (2014-2025). Patients with prior surgery or radiation to the index lesion were excluded. EOR was determined on postoperative contrast-enhanced MRI within 48 hours. Overall survival (OS) and freedom from LR and LMD were estimated using Kaplan-Meier methods. Multivariable Cox regression for OS included EOR, recursive partitioning analysis class, histology, and number of brain metastases.
Results
Eighty-four patients were included (median age 64.3 years; lesion volume 11.3 cm3); 49% had multiple metastases. Gross total resection (GTR) was achieved in 48/65 evaluable cases (73.8%). Median estimated blood loss was 50 mL, postoperative length of stay 3 days, and 30-day mortality 3.6%. Median OS was 302 days (95% CI, 211-644). GTR was associated with improved OS vs subtotal resection (STR) on univariate analysis (median 462 vs 206 days, p = 0.039) and showed a trend toward lower hazard of death on multivariable analysis (HR 0.51, 95% CI 0.25–1.03, p = 0.062). Among patients with ≥2 months imaging follow-up, 1-year freedom from LR was 85% after GTR versus 51% after STR (p = 0.0005); GTR remained independently associated with lower risk of LR after adjustment for adjuvant radiation (HR 0.15, 95% CI 0.04–0.55, p = 0.004). One-year freedom from LMD was 89%.
Conclusions
Tubular retractor-based resection of brain metastases achieves favorable perioperative outcomes with preserved oncologic efficacy, despite piecemeal resection. EOR remains a key modifiable determinant of local control.