Significance and Priority of Surgical Resection as Therapeutic Strategy Based on Clinical Characteristics of Brain Metastases from Renal Cell Carcinoma

Objective: To clarify a rational surgical priority, clinical characteristics were compared between brain metastases (BM) from renal cell carcinoma (RCC) and other cancers.

Methods: We reviewed 425 consecutive patients with BM who underwent treatments including surgery between January 2014 and December 2022. Primary cancers included lung (n = 220), breast (n = 46), digestive (n = 65), RCC (n = 25), and others (n = 69). Tumor volume (T), edema volume (E), and edema volume/tumor volume ratio (E/T ratio) were compared between RCC and other primary cancers. Cutoff T values for identifying both symptomatic tumors and tumors suitable for surgery were determined by receiver operating characteristic curves. Factors including E/T ratio, age, Karnofsky Performance Scale score, and tumor characteristics were statistically analyzed.

Results: Cutoff values of T and E to determine surgical suitability were 4.973 cm3 (sensitivity, 0.848; specificity, 0.74) and 23.088 cm3 (sensitivity, 0.894; specificity, 0.623), respectively. E/T ratio was significantly higher for RCC than for other cancers (P < 0.01). These results remained consistent after propensity score matching. RCC tended to show a significantly lower frequency of posterior fossa tumor (16%, P < 0.01) and higher rates of single lesions (72%, P = 0.03) and intratumoral hemorrhage (24%, P = 0.02). Subgroup analysis limited to surgical cases showed that E was consistent across tumors, T tended to be smaller, and E/T ratio was significantly higher in RCC.

Conclusions: Generally, symptomatic BM were indicated for surgery. BM from RCC were characteristically single, low-volume lesions with expanding edema and intratumoral hemorrhage, causing symptoms. These results suggest that surgery should be a high priority for BM from RCC.