Classification of the 16,471 patients treated by radiation therapy from 1962 to 1986, and crude five-year survival rates of patients in each category of radiotherapy treatment from 1962 to 1978 in the National Cancer Center Hospital.

The summation and classification of patients registered for planned radiation therapy in the 24-year period from 1962 to 1986, in the Department of Radiation Therapy, National Cancer Center Hospital, are reported. Patients numbered 16,471, and total sessions of treatment were 26,175. The ratio of the two figures, 1.58, is the average number of treatment sessions per patient. Peak age was 61-65 years' old and 56-60 years old, respectively for males and females. The most frequent primary site of disease for radiation therapy was the head and neck, followed by trachea, bronchus and lung, crevix uteri, breast, and esophagus. Frequency of squamous cell carcinoma was 38.0%; that of adenocarcinoma was 20.9%. Radical treatment was performed in 32.0% of patients in the first session, but this figure decreased to 24.7% for all sessions. There were many cases of secondary and primary palliative treatment, i.e., 31.8%. Radiotherapy was done in 70% of patients by megavoltage X-ray, with 9.4% treated by electron beam. Crude 5-year survival rates for each classification of malignant disease respective to the category of treatment policy from 1962 to 1978 were obtained. Among the radical treatment group, head and neck tumors, skin cancer, and Hodgkin's disease showed 5-year survival rates greater than 50%.

Clinical experience with the 22-MeV microtron at the National Cancer Center Hospital.

Experience with the 22-MeV microtron is presented. The maintenance and ease of operability of the system are satisfactory. The physical characteristics showed many clinical advantages. Fundamental measurement of dose distribution and depth dose curves were performed and clinically applied. The two-gantry system is very satisfactory and effective for irradiation by photons and electrons to treat many patients per day. The facility for intraoperative radiotherapy and the physical conditions for total body irradiation are also sufficient because of the well-designed building layout and the systematized facility with the microtron system.

Afterloading technique for interstitial irradiation of lesions in deep-seated organs.

An afterloading procedure using iridium 192 seeds was developed for the control of both localized primary lesions that are difficult to remove and superficial residual lesions that remain after the partial removal of tumors in relatively inaccessible, deep-seated organs. This technique makes possible the delivery of a minimal radiation dose to lesions in deep-seated organs. Fewer complications result, the seeds can be adjusted at appropriate intervals in proportion to the amount of radioactivity desired, and radiation exposure to personnel can be reduced. This paper describes the techniques and apparatus used to place the seeds in the tubing. Primary lesions of the urinary bladder, the prostate gland, and the esophagus, residual lesions in the brain and lung, and metastases in intrapelvic lymph nodes were treated. No technical difficulties or complications were encountered. Radiation exposures to personnel were minimized. The results indicate that the procedure has practical applications.