[Serum ferritin level for estimating the effect of the radiotherapy]

Serum ferritin level was evaluated as a marker for estimating the effect of the radiotherapy. The ferritin level was determined by a radioimmunoassay (SPAC ferritin kit) in sera obtained serially from 37 patients with various malignant neoplasma before and after radiotherapy. The changes in the ferritin level were investigated in comparison with various clinical findings. The decision for significant changes in the ferritin level was made by the sensitivity which is a difference value necessary to discriminate 2 values at confidence level of 95%. Out of 11 cases with clinical evidence of distant metastasis, the ferritin level was decreased in only one case (9%) and increased or unchanged in the rest. On the other hand, out of 26 cases without evidence of metastasis it was decreased in 9 cases (35%) and unchanged in 12 cases (46%). The ferritin level was either decreased (64%) or unchanged (36%) in all the 11 cases with operation prior to radiotherapy, while out of 26 cases without operation (inoperable) it was decreased in only 3 cases (12%). In all 5 cases with radiosensitive tumors as judged by tumor size the ferritin level was either decreased (40%) or unchanged (60%). Out of 28 cases with radioresistant tumors it was decreased in only 4 cases (14%). All of these results indicated that serial measurements of the ferritin level is usefull for estimating the therapeutic effectiveness in radiotherapy.