METASTATECTOMY SHOULD BE FOLLOWED BY WBRT?

Brain Surgery for Metastasis Tied to Distinctive Tumor Spread

NEW YORK (Reuters Health) - In the absence of whole-brain radiation, neurosurgical resection in patients with brain metastases may boost pachymeningeal seeding, a new study hints.

"Historically, patients undergoing neurosurgical resection for a brain metastasis have received adjuvant whole-brain radiation, but recently published randomized trials have concluded that quality of life and neurocognitive function are better with adjuvant stereotactic radiation to the cavity in lieu of whole-brain radiation," said Dr. Daniel N. Cagney of Dana-Farber/Brigham and Women's Cancer Center, in Boston.

"However," he told Reuters Health by email, "withholding whole-brain radiation from management paradigms may permit tumor propagated by the process of neurosurgical resection to recur in distant intracranial locations."

Dr. Cagney and colleagues examined intracranial recurrence patterns in 1,188 patients with newly diagnosed brain metastases treated with or without neurosurgical resection between 2001 and 2015.

"We found no differences in the likelihood of leptomeningeal disease in the two cohorts but we did identify multifocal pachymeningeal recurrences (pachymeningeal seeding) which only occurred in the neurosurgical cohort (P<0 .001="" he="" p="" said.="">

Thirty-six of 318 patients in the neurosurgical cohort showed such seeding compared to none of the 870 patients treated with radiation alone, the researchers report in JAMA Oncology, online March 7. The median survival from the time of diagnosis of pachymeningeal disease was 11.1 months.

Dr. Cagney said the results "suggest that pachymeningeal seeding represents a pattern of intracranial disease progression that is unique to patients undergoing neurosurgical resection and has a different natural history than leptomeningeal disease. To the best of our knowledge, postoperative pachymeningeal seeding has not been described in the literature beyond isolated case reports."

"Our study," he concluded, "suggests that evaluation of neurosurgical techniques that can reduce the likelihood of pachymeningeal seeding warrant investigation. Clinical trials evaluating leptomeningeal disease as a primary or secondary endpoint in patients with brain metastases should delineate pachymeningeal seeding from leptomeningeal disease."

Dr. Ganesh Rao of the University of Texas MD Anderson Cancer Center, in Houston, who was not involved in the study, noted that although the rate of pachymeningeal enhancement was much higher for those who had surgery, "An important caveat is that patients undergoing surgery had very large lesions (between 3-4 cm) with rapid growth, and neurological symptoms."

"Thus, these patients needed the surgery, but we must find better ways to improve local tumor control after the procedure and reduce the risk of pachymeningeal disease which can contribute to mortality," Dr. Rao, who is a professor of neurosurgery, told Reuters Health by email.

SOURCE: https://bit.ly/2HvIm5y

JAMA Oncol 2019.