MOST RADIOTHERAPISTS have the clinical impression that the radiation response of cancer in anemic patients is diminished. Statistically valid data are scarce in support of this opinion or as to whether anemia influences radiation curability or only the speed of regression. The radiation response of skin and tumor transplants in rats made anemic by bleeding was studied as early as 1932 (6). The results of this investigation, although equivocal, suggested diminished radiosensitivity of both skin and tumor in the anemic animals. The main problem in testing the validity of this impression in human cancer has been to find a large group of patients with a rather homogeneous type of cancer, treated by a standardized technic and carefully followed. They must also have a high incidence of anemia, not corrected before irradiation. Such clinical material was found in cases of carcinoma of the uterine cervix treated in the gynecologic department of the Norwegian Radium Hospital during the years of the Second World War. Material The case records of 895 patients with cancer of the cervix treated from 1940 through 1945 were examined initially. Subsequently, an additional 490 records of cervix carcinoma (Stages II and III) treated during 1956 through 1958 were reviewed, as will be described. The radium treatment throughout these years remained quite standardized. It consisted of an intrauterine tandem containing 20 or 30 mg of radium and an individually molded vaginal applicator containing 30 mg of radium. These were usually applied separately for a period of five days, although in early cases both insertions were sometimes made simultaneously. The dosimetry of this system has been reported elsewhere (2). Usually external radiation with 175 kvp, giving 3,000 R (skin) to four large pelvic fields, was added after the radium insertions, particularly in the more advanced stages of disease. For the later time period studied, betatron radiation (31 Mev x rays) was administered, with 4,000 R (measured by a Victoreen ionization chamber) delivered to the midpelvis after the radium insertions. All cases were confirmed histologically. There were 26 adenocarcinomas during the war years; these have not been separated from the remaining squamous-cell or anaplastic carcinomas. No cases were lost to follow-up. Incidence of Anemia It was suspected that dietary deficiencies in occupied Norway, plus blood loss from uterine cancer, would cause anemia in a large number of patients treated during these years. We have arbitrarily set 11 g per cent, 80 per cent of the accepted “normal value” of 13.8 g per cent, for these years as the border between normal and abnormal hemoglobin concentration. In 15 cases, hemoglobin was not determined prior to radium therapy. One-fourth of the remaining patients were anemic by this standard (Table I).