The threefold value of surgery in previously irradiated brain metastases

Differentiating radiation necrosis (RN) from tumor recurrence (TR) in previously irradiated brain metastases (BM) remains a challenge. Imaging techniques lack sufficient diagnostic reliability, while therapeutic implications differ between both entities. This study aims to evaluate the diagnostic, therapeutic, and prognostic value of surgery in patients with progressive irradiated BM.

We studied patients who underwent surgical resection for progressive BM after prior irradiation. Histopathological diagnosis was classified as pure RN or TR. Clinical, radiological, surgical, and survival outcomes were analyzed.

In 73 lesions, histopathology demonstrated TR in 68.5% of lesions. Among TR, 84.0% showed mixed pathological features combining viable tumor cells and radionecrotic patterns. Patients initially treated by irradiation alone were significantly more likely to present TR, whereas surgery followed by postoperative irradiation was significantly associated with RN. Median interval between radiation and surgery was significantly longer in the RN group and breast cancer seemed related to RN. Postoperative clinical improvement occurred in 80.4% of symptomatic patients and corticosteroid discontinuation within one month occurred in 72.3% of patients, without significant difference between RN and TR. Median overall survival was longer in patients with RN (39 vs. 19 months, p = 0.025).

Surgery provides diagnostic, therapeutic, and prognostic value in patients with progressive irradiated BM. Beyond diagnostic clarification, surgery provides significant symptomatic improvement and corticosteroid withdrawal regardless of final pathology. Histopathological diagnosis influences survival outcomes and subsequent oncological management.