{"id":704288,"date":"2026-06-14T22:06:14","date_gmt":"2026-06-14T22:06:14","guid":{"rendered":"https:\/\/www.newsbeep.com\/us\/704288\/"},"modified":"2026-06-14T22:06:14","modified_gmt":"2026-06-14T22:06:14","slug":"11-massachusetts-nurses-were-diagnosed-with-brain-tumors-is-it-a-cancer-cluster","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us\/704288\/","title":{"rendered":"11 Massachusetts nurses were diagnosed with brain tumors: Is it a ‘cancer cluster’?"},"content":{"rendered":"

As the state investigates a possible cancer cluster at a high school<\/a>, many Herald readers have asked whatever happened with the potential tumor cluster at a local hospital.<\/p>\n

Seven current and former nurses in Newton-Wellesley Hospital\u2019s fifth floor maternity wing were diagnosed with brain tumors<\/a>, the Herald reported last year.<\/p>\n

The number of current and former nurses with confirmed or suspected brain tumor diagnoses was actually 11, the Herald has learned while reviewing an independent report of the tumor concerns at the hospital<\/a>.<\/p>\n

Ultimately, the outside expert from Harvard determined there\u2019s no evidence of \u201ca true workplace tumor cluster\u201d at the Mass General Brigham facility.<\/p>\n

Stefanos Kales, a professor at Harvard Medical School, in the external report stressed that the hospital workplace is a safe environment \u2014 and is not the cause of the brain tumors.<\/p>\n

There was no evidence of \u201cany adverse or harmful chemical or other exposures,\u201d he wrote. A series of independent assessments found \u201cno excess radiation exposure.\u201d<\/p>\n

\u201cThus, all available information and data indicate that the NWH 5th floor is a safe working environment without evidence of any carcinogenic\/ tumorigenic occupational exposures,\u201d wrote Kales, who\u2019s also professor and director of the Occupational Medicine Residency at the Harvard Chan School of Public Health.<\/p>\n

\u201cThe most important finding of this review is that multiple comprehensive exposure assessments done to examine the NWH 5th floor environment found no evidence of any potential occupational exposure that could cause brain tumors,\u201d Kales added. \u201cThe likelihood of a true environmental tumor cluster in\u00a0the absence of plausible exposures is very unlikely.\u201d<\/p>\n

When news broke last year of the several nurses being diagnosed with brain tumors, hospital officials continued to assure staff and patients that the environment was safe.<\/p>\n

After hospital officials learned of the reported brain tumors, they launched an investigation. Experts reviewed air and water quality, and conducted comprehensive testing for any potential radiation, chemical, or pharmaceutical exposures.<\/p>\n

Hospital officials in recent months updated employees about the fifth floor environmental investigation, and the conclusion of the external reviews.<\/p>\n

\u201cTheir findings align with all previous assessments: no environmental risks have been identified in the hospital workplace,\u201d Ellen Moloney, hospital president and COO, wrote to employees. \u201cThese evaluations included extensive testing of air quality, water quality, radiation exposure, chemical and pharmaceutical safety, interviews with current and past staff, and a detailed review of potential risk factors.<\/p>\n

\u201cNo exposures or environmental conditions were identified that could cause the types of benign brain tumors reported,\u201d Moloney added.<\/p>\n

In Kales\u2019 external report, more details were shed about the diagnosed nurses who worked in the maternal care labor\/delivery unit on the hospital\u2019s fifth floor at some point over the last 23 years. All of the nurses with brain tumors are women.<\/p>\n

Nine of the 11 brain tumors were considered benign or not malignant. Six were meningiomas, the most commonly reported brain tumors in the country. Two were pituitary adenomas, and one was an optic nerve schwannoma.<\/p>\n

The two malignant tumors were glioblastoma and glioma.<\/p>\n

\u201cThe types of prevalent tumors and their proportions among the NWH 5th floor employees were compared statistically to the proportions of different tumor types in national United States surveillance data on brain tumors,\u201d wrote Kales, who\u2019s also the chief of Occupational Medicine and Medical Director for Employee Health\/Industrial Medicine at the Cambridge Health Alliance.<\/p>\n

\u201cThe distribution of brain tumor types was remarkably similar to national data with no statistically significant differences in the frequency of these tumor types on the NWH 5th floor and national data for brain tumors,\u201d he added.<\/p>\n

Kales evaluated latency considerations, which is the required lag time from when a person is first exposed to a carcinogen until a tumor grows to a diagnosed size. Most solid tumors in adults have a minimum latency of at least 10 years.<\/p>\n

\u201cAmong the six NWH 5th floor employees with confirmed or suspected meningiomas, the latency ranged from 1 to 18 years and 3 of the 6 cases had less than 7 years of latency. Thus, at least three of the six cases were not compatible with a hypothesis of causation by radiation or other occupational exposure,\u201d Kales wrote.<\/p>\n

Among the two reported pituitary adenomas, one case had less than five years of latency. That also eliminated the possibility of a pituitary cluster.<\/p>\n

\u201cAmong the two reported gliomas, each had a latency of 20 years, and therefore, no potential latency\u00a0issues are present,\u201d Kales wrote. \u201cHowever, overall biological plausibility is lacking as there are no known, no\u00a0reported and no measured carcinogenic\/ tumorigenic exposures.\u201d<\/p>\n

As more brain tumor cases were reported from the fifth floor maternity wing, many hospital employees grew increasingly concerned.<\/p>\n

\u201cThe perception of a cancer cluster and\/or concerns regarding the surrounding environment among\u00a0the involved population may exist despite the absence of a true cancer cluster,\u201d Kales wrote. \u201cEpidemiologists\u00a0define a true cancer cluster as the confirmed observation of cases of the same or etiologically\u00a0related cancers in numbers greater than the expected number during a specific time among a discrete group of people (defined by geography, workplace, etc.).\u201d<\/p>\n

He added, \u201cTrue clusters are generally rare and sufficient evidence of occupational\/environmental causation is very unusual\u2026 Although the\u00a0occurrence of these tumors may seem related or have some association in the eyes of the\u00a0community, they are medically distinct and unrelated phenomena.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"As the state investigates a possible cancer cluster at a high school, many Herald readers have asked whatever…\n","protected":false},"author":2,"featured_media":704289,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[34],"tags":[108756,687,304307,97,1493,304310,70536,2001,41660,304308,70942,47814,304309,133792],"class_list":["post-704288","post","type-post","status-publish","format-standard","has-post-thumbnail","category-health","tag-brain-tumors","tag-cancer","tag-cancer-cluster","tag-health","tag-hospital","tag-hospital-nurses","tag-mass-general-brigham","tag-massachusetts","tag-newton","tag-newton-wellesley-hospital","tag-nurse","tag-nurses","tag-tumor-cluster","tag-tumors"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/704288","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=704288"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/704288\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/704289"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=704288"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=704288"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=704288"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}