CARCINOGENESIS BY IONIZING RADIATIONS 1151 



The first two cases of carcinomas of the skin from exposure to radia- 

 tions from radium occurred in handlers of radium tubes and applicators 

 and were described in 1923 by MacNeal and Willis and in 1927 by 

 Wakely. Both patients had years of repeated exposures. The lesions 

 began with numbness in finger tips, roughness of the skin of the hand, 

 and tingling sensation; later the nails were friable and fissured, the skin 

 atrophic and thin but not ulcerated. Telangiectasias appeared and light 

 brown pigmentations and hyperkeratoses; one of the last showed, on 

 section, a squamous-cell carcinoma. These, as many other patients 

 suffering from neoplasms induced by irradiation, were treated with 

 radium, X radiation, and sunlight, which are carcinogenic (Colwell and 

 Russ, 1934). This paradox is frequently discussed. Treatment with 

 ionizing radiation causes regression of neoplasia within days or weeks 

 but is carcinogenic only after several years and only under special 

 circumstances. 



Lazarus-Barlow (1918, 1922) was the first to induce cancer of the skin 

 by radioactive substances. He introduced radium sulfate or silicate into 

 the subcutaneous tissue of mice and observed the development of five 

 malignant tumors of the skin in sixty-seven animals surviving six months. 

 He was also believed to have induced cancer of the gallbladder by insert- 

 ing radium in cholesterol stones and placing the stones in the gallbladder, 

 but this was disputed by others. The character of an epithelial prolifera- 

 tion is often difficult to assess and extensive hyperplasia may mimic neo- 

 plasia, notably in the gallbladder or uterus, where, without being neo- 

 plastic, nests of epithelial cells may be established in deeper layers. 



Slowly, clinical reports multiplied on induction of neoplasms in man by 

 therapeutic irradiations. On the other hand, experimental work on this 

 subject slackened until World War II, when developments in nuclear 

 physics introduced the use of ionizing radiation in warfare and expanded 

 tremendously its use in medicine and industry. 



NEOPLASIA INDUCED BY X AND GAMMA RADIATION 



Since 1902 when skin tumors were first observed on hands of persons 

 who developed radiodermatitis, clinical reports appeared in steadily 

 increasing numbers, at first on the development of cutaneous and later 

 on internal tumors. The prophecy "La radiotherapie ne donne pas les 

 cancers" (Belot, 1910) is now a reminder of the danger of drawing such 

 negative conclusions. In 1911 Hesse surveyed a total of ninety-four 

 cases, to which 126 cases were added by Krause in 1930. The clinical 

 aspects of malignant growths induced in man are described in over thirty 

 publications which cannot be cited here. Most of these deal with 

 tumors of the skin and only a few with those of deep-seated organs, e.g., 

 uterus, ovary, and larynx, and it became a matter of dispute whether 



