I. Introduction IT has been my privilege to know your chairman, Dr. Garland, for several years. On the occasion of the meeting of the American College of Surgeons in San Francisco, in 1935, he organized, under the chairmanship of Dr. Newell, a round table conference of roentgenologists which was for me the most instructive I have ever attended. When Dr. Garland first invited me to address you, he suggested as a topic, “The Present Philosophy and Methods of Treating Cancer of the Larynx.” This proposal indicates to us that its author is philosophically inclined and that he is surely a “friend of wisdom,” a beautiful example for us all. But roentgen therapy seems to me truly too young and its steps altogether too hesitating to warrant us in clothing it in such purple robes. I, therefore, asked Dr. Garland to substitute for this majestic title the humble one of “The Present Conception of the Treatment of Cancer of the Larynx.” Even with this far more modest title, I still permit myself to bring to you some new general ideas based upon the results of the clinical facts I have observed during the last twenty years. II. Results of Roentgen Therapy of Cancer of the Larynx From 1921 to 1932 we treated with x-rays, in the Curie Institute, 142 patients with cancers of the larynx which were either inoperable or post-operative recurrences. Of these, 39, or 27 per cent, have survived five years without symptoms. Nineteen out of 87 patients, or 22 per cent, treated between 1921 and 1927, have survived 10 years without symptoms. Six out of 31 cases, or 19 per cent, treated between 1921 and 1923, have survived 15 years and are symptom-free. The curve of the five-year symptom-free survivals considered by years shows a great irregularity in the results. If, however, we examine the results obtained during these years, from the point of view of the types of cancers, then we see that the three best years, 1921, 1926, and 1932, have given 50, 52, and 66 per cent five-year cures, and the years 1921 and 1926, 50 and 3.5 per cent 1O-year cures. This means that during these years the radiosensitive cancers predominated.2 On the contrary, the proportion of radioresistant cancers has been maximal during the bad years, with the following five-year survivals: 0 per cent in 1922, 16 per cent in 1923, 8 per cent in 1924, 14 per cent in 1929, and 16 per cent in 1930. The years with medium results, that is, 1925, 1927, 1928, and 1931, show 35, 20, 20, and 28 per cent, respectively, of five-year survivals because the proportion of cancers with late radiosensitivity has been smaller than in the second group and larger than in the first group. In fact, the total proportion of five-year survivals in cancers of early radiosensitivity has been 75 per cent and in cancers with late radiosensitivity 6 to 8 per cent. Cases of the former type have been easily curable.