The first effective chemotherapies were developed in the 1940s.
Notes on verification
Well-corroborated by NCI, NIH/PMC, and Science History Institute sources. Nitrogen mustard (1942-43) and aminopterin (1947-48) are consistently cited as the first chemotherapy agents producing measurable clinical remissions, marking the historical start of the chemotherapy era, though 'effective' is interpreted loosely as inducing temporary remission rather than cure.
Sources
- A visual history of cancer | Wellcome Collection (wellcomecollection.org)
- https://www.cancer.gov/research/progress/250-years-milestones (cancer.gov)
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790689/ (ncbi.nlm.nih.gov)
- https://www.sciencehistory.org/education/scientific-biographies/sidney-farber/ (sciencehistory.org)