Expectation of aplastic anemia following radiotherapy for malignancy.

In Japan after 1969, 11 cases of aplastic anemia following radiotherapy for malignant disease were detected. The population at risk in irradiated patients was estimated at 674, 664 man-years. The expected cases of aplastic anemia in this population were calculated as 10.1. There is no statistically significant difference between the expected and the observed values.