[Dr. Stéphane Leduc and the first treatments of cancer by irradiation in Nantes and France].

In August 1883, a Chair of physics was created in Nantes with Dr. Leduc (1853-1939) as the first teacher. Physician and biophysicist, he was a pioneer and visionary in many areas, including the "synthetic biology". Dr. Leduc immediately understood the importance of the discovery of the X-ray by Röntgen in 1896 for medicine. As early as in 1905, he successfully treated cancers with irradiation. In 1935, he was awarded a gold key by the American Congress of Physical Therapy for his accomplishments. The teachings of Dr Leduc largely influenced his student and successor, Dr René Gauducheau's (1881-1968) orientation towards physical and radiological sciences. This latter introduced radium therapy, and began his endeavor for the creation of a cancer center which opened its doors in 1924, recently becoming the Institut de Cancérologie de l'Ouest in 2011.