Third Estimate on Nurse Brain Tumors
Post #1227
The prior post on this topic is here.
Using the verified number of brain tumors found in the nurses at Newton-Wellesley Hospital in Massachusetts, along with a lower estimate of the total number of nurses associated with that hospital, along with a narrowed estimate of expected brain tumors using numbers appropriate for adults, here is the result:
[click image to enlarge]
Cell B9 shows that, of all brain tumors found in people, 5.7% of them are found among those under age 20. Applying this to the total number of persons affected you can find the total number of adults experiencing brain tumors, which can be divided by the total adult population, producing the yearly expected rate for adults (cell C20).
When checking for “health-issue clusters” then the Standardized Incidence Ratio (SIR) is computed, but it is nothing other than the observed number of cases found divided by the expected number of cases found. Using a 3-year time-window for the accrual of the 5 confirmed brain tumors gives an SIR of 14.1 with 3.0 as the 99% lower bound.
The chance to coincidentally find all 5 tumors over 3 years is about 1-in-29,000 (O12).
Cell I18 is selected so that you can see the formula used in order to find the 99% lower bound. When you have count data which has an expected value, then that fancy formula will find out any percentile value for your count. In the current form:
=GAMMA.INV(0.005,F18,1)/G18
It finds the [0.5]th percentile value for a count, using an observed value found in cell F18, giving the low estimate of that count — which is then divided by an expected value found in cell G18 in order to produce the lower bound on the SIR. Here is where the percentage of all brain tumors occurring in kids was taken from:
That allowed for the removal of all tumors expected to have been found in kids, leaving only those tumors expected to have been found in adults — to get even more precise when forming expectations regarding brain tumors in nurses (who are all adults). Even with just the 5 confirmed tumors, this qualifies as a “health-issue cluster.”
Reference
[5 brain tumors have been confirmed so far] — https://nypost.com/2025/04/04/health/multiple-nurses-get-brain-tumors-in-the-same-hospital-unit/
[all-ages yearly brain tumor rate is 27 per 100,000] — Ostrom QT, Price M, Neff C, Cioffi G, Waite KA, Kruchko C, Barnholtz-Sloan JS. CBTRUS Statistical Report: Primary Brain and Other Central Nervous System Tumors Diagnosed in the United States in 2015-2019. Neuro Oncol. 2022 Oct 5;24(Suppl 5):v1-v95. doi: 10.1093/neuonc/noac202. PMID: 36196752; PMCID: PMC9533228. https://pmc.ncbi.nlm.nih.gov/articles/PMC9533228/
[5.7% of brain tumors are in those under age 20] — https://braintumor.org/brain-tumors/about-brain-tumors/brain-tumor-facts/
[men aged 20 and older] — U.S. Bureau of Labor Statistics, Population Level - 20 Yrs. & over, Men [LNU00000025], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/LNU00000025
[women aged 20 and older] — U.S. Bureau of Labor Statistics, Population Level - 20 Yrs. & over, Women [LNU00000026], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/LNU00000026