Surgical Outcomes of Canine Intracranial Meningioma With or Without Radiation

Meningioma is the most common primary brain tumor in dogs, and recurrence after treatment presents a significant clinical challenge. This retrospective study evaluated prognostic factors in 21 dogs with intracranial meningioma treated with surgical resection alone or with postoperative radiation therapy (RT). Recurrence rate, progression-free survival (PFS), median survival time (MST), and prognostic indicators were assessed. Of the 21 dogs, 13 received adjuvant RT. Local recurrence was noted in six dogs (28%). Overall MST was 845 days, and PFS was 771 days. By treatment group, MST was 886 days for surgery alone and 845 days with RT; PFS was 886 and 531 days, respectively, with no significant statistical difference. Grade 1 tumors and intact male status were associated with favorable outcomes (P < .05). All grade 1 cases (n = 5), treated with surgery alone, showed no recurrence, whereas all recurrences occurred in grade 2 (n = 3) or unknown-grade tumors (n = 3), most receiving radiation. RT was well tolerated but did not show statistically proven efficacy. However, the benefit of postoperative RT could not be determined due to selection bias.