Pachymeningeal Seeding After Neurosurgical Resection in Patients With Brain Metastases


Key Points

  • Pachymeningeal seeding was observed in 11% of patients undergoing resection.
  • Resection was not associated with a significantly increased risk of leptomeningeal disease.

In a retrospective cohort study reported in JAMA Oncology, Cagney et al found that pachymeningeal seeding was fairly common after neurosurgical resection in patients with brain metastases treated with adjuvant stereotactic radiation.

Study Details

The study involved 1,188 consecutive patients with newly diagnosed brain metastases treated at Brigham and Women’s Hospital/Dana-Farber Cancer Institute with neurosurgical resection and stereotactic radiation (n = 318) or radiation alone (n = 870) between 2001 and 2015. Patients were assessed for incidence of pachymeningeal seeding (dural or outer arachnoid) and leptomeningeal disease.

Risk of Pachymeningeal Seeding

Pachymeningeal seeding was found to occur in 36 (11%) of 318 patients undergoing resection vs 0 of 870 patients undergoing radiation therapy alone (P < .001). Resection was not associated with a significantly increased risk of leptomeningeal disease (hazard ratio [HR] = 1.14, P = .56).

Overall, 36 (8.4%) of 428 operations were associated with pachymeningeal seeding, with risk being greater with resection of previously irradiated vs nonirradiated metastases (HR = 2.39, P = .008). Patients with pachymeningeal seeding accounted for 8 (16%) of 51 cases of new brain metastases and 6 (13%) of 48 cases of leptomeningeal disease. Neurologic death primarily due to progressive pachymeningeal disease accounted for 26 (72%) of 36 deaths among patients with pachymeningeal seeding. Treatment of patients with pachymeningeal seeding with salvage radiotherapy was associated with improved overall survival (≥ 1 year).

The investigators concluded, “In the era of omission of adjuvant whole-brain radiation after neurosurgical resection, pachymeningeal seeding beyond the stereotactic radiation field represents a notable oncologic event that often proves difficult to salvage. However, in some patients, disease control can be achieved with radiotherapeutic approaches.”

Daniel N. Cagney, MD, of the Department of Radiation Oncology, Dana-Farber/Brigham and Women’s Cancer Center, is the corresponding author for the JAMA Oncology article.

Disclosure: The study authors' full disclosures can be found at

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