An independent review has concluded that Newton-Wellesley Hospital was not the cause of the brain tumors diagnosed in 11 current and former nurses who worked in its fifth-floor maternity wing. The report, released in 2026, said the hospital workplace is safe and found no evidence of a true workplace tumor cluster at the Mass General Brigham facility.
The finding addresses a question that had shadowed the hospital since the cases came to light: whether the tumors reflected a workplace hazard. The answer from the Harvard professor who led the review was no. The report said there was no evidence of “a true workplace tumor cluster,” even though the concern involved 11 women who had all been diagnosed with brain tumors.
The diagnoses included six meningiomas, two gliomas, two pituitary adenomas and one schwannoma of the optic nerve. Except for the gliomas, the other nine tumors were considered benign. The cases ranged across nurses hired as far back as 1990-1999 and as recently as 2020-present, with some diagnoses confirmed by imaging and others by tissue.
Among the 11 were a woman in her 30s hired in 2010-2019 whose meningioma was confirmed by tissue, a woman in her 60s hired in 1990-1999 with an optic nerve schwannoma diagnosed by imaging, and two nurses hired in 2000-2009 who had glioma and glioblastoma diagnoses confirmed by tissue. Others had meningiomas or pituitary tumors identified by imaging or tissue, including one possible meningioma.
What the report did not answer is what caused the tumors. It clears the hospital as the source of the cluster concern, but it leaves the underlying cause of the nurses’ illnesses unresolved. For now, the outside review gives the hospital the formal conclusion it was seeking, while the cause of the tumors remains unknown.
