To the editor:
I have sympathy for anyone with cancer and realize many people are looking for a reason as to what caused it, but Roundup (glyphosate) is certainly not the reason.
Nancy Riege suggests in her letter to the Hardwick Gazette that her mother’s non-Hodgkin lymphoma (NHL) could have been caused by her use of Roundup in the 1960s and 1970s. However, most of this time-frame predates the introduction of Roundup, first marketed in 1974, with dramatic increase in use only after 1995.
There are many contradictory conclusions as to whether Roundup causes cancer. The most frequently cited source is IARC, an agency within the World Health Organization (WHO), which concluded that glyphosate is a probable cause of cancer. IARC’s conclusion was based on an assessment of hazard: could glyphosate cause cancer at some dose and schedule, but according to IARC, almost everything causes cancer. They did not consider risk which also assesses likely exposure. For example, IARC (and the referenced Panzacchi et al paper from 2025) fed rats glyphosate daily for up to two years. This is a life-time exposure for rats and is far beyond that for a person using glyphosate for a few days around the garden or to kill Japanese knotweed, and hopefully consuming none. Furthermore, IARC classified glyphosate as a Class 2A carcinogen along with red meat, hot beverages and many common medicines, and less hazardous than bacon, salted fish, oral contraceptives and wine, among many examples.
The critical question is whether glyphosate has caused cancer in humans. The American Cancer Society provides excellent statistics. NHL is a common cancer, with a lifetime risk of 1/50. There are more than 80,000 cases in the USA each year. This incidence has not changed since the introduction of Roundup (apart from a slight increase before 1990 attributed to HIV). There has been no further increase and even a decline since 2010.
If glyphosate caused NHL, its incidence would have increased following exposure, plus some lag time. For comparison, there is well-recognized 20-year lag between smoking tobacco and the incidence of lung cancer. No such increase in NHL has occurred.
IARC’s conclusion contradicts three other WHO agencies as well as the EPA and regulatory agencies in the many other countries who did independent evaluation of the available data. To believe that glyphosate causes cancer, one would have to believe in a coordinated world-wide conspiracy involving all these agencies.
Alan Eastman
Groton
