PubMed1980
In a total of 1,828 determinations, urinary excretion of 5-S-Cysteinyldopa was studied over a period of three years in 384 patients treated for melanoma or with metastases of malignant melanoma. By serial investigations the excretion of 5-S-Cysteinyldopa was compared to the course of the disease. In the case of small and circumscribed metastases which could be eliminated by surgical treatment, the excretion of 5-S-Cysteinyldopa remained normal. When the disease became generalized, an increase of the urinary excretion of 5-S-Cysteinyldopa prior to the clinical manifestation of the metastases was observed in only four out of 26 cases. In the remaining cases, the increase of 5-S-Cysteinyldopa coincided with the manifestation of metastases, or the excretion of the substance became pathological when the metastases were already conspicuous. In five patients, the urinary excretion of 5-S-Cysteinyldopa remained normal inspite of widespread disease. Therefore, its diagnostic value seems to be similar to that of the "common" laboratory investigations the results of which are only pathological when the disease has already become generalized. Our investigations demonstrate that serial investigations of the urinary excretion of 5-S-Cysteinyldopa only rarely indicate melanoma metastases prior to their clinical manifestation. In cases of early metastasing melanoma, all common laboratory investigations are of limited value. BSR and GGT levels which become pathological very early in the course of the disease are so sensitive that slightly pathological levels may be ambiguous. In these cases, however, pathological levels of 5-S-Cysteinyldopa most probably will indicate a widespread disease.