The value of cysteinyldopa in the follow-up of disseminated malignant melanoma

In a series of 92 patients with malignant melanoma, clinical stage III or I V, both 5-S-cysteinyldopa (5SCD) and 6-hydroxy-5-methoxyindole-2-carboxylic acid (6H5MI2C) were measured in urine during chemotherapy. A total of 434 urine specimens were analysed. The sensitivity of 5SCD for the detection of stage III-IV melanoma was 83%, while the corresponding sensitivity of 6H5M I2C was 52%. Fifty per cent of patients with one metastatic site had increa sed 5SCD excretion, while all patients with four or more metastatic sites h ad increased excretion. A significant correlation was found between 5SCD de crease and clinical regression (P < 0.001) and between 5SCD increase and cl inical progression (P < 0.001). Corresponding correlations were not found f or 6H5MI2C. Increments in 5SCD excretion (median 269 mu mol/mol creatinine) were seen for 83% of the occasions when clinical progression was recorded, and decrements in 5SCD excretion (median 145 mu mol/mol creatinine) were s een for 85% of the occasions when clinical regression was seen. During clin ical 'stable disease' increases in 5SCD excretion were seen in 59% and decr eases in 41%. The median value of 5SCD changes for stable disease was 7.0 m u mol/mol creatinine, indicating a chemical marker stability in many cases. We recommend the use of 5SCD in urine as a valuable, reliable and simple b iochemical marker to use in the clinical follow-up of melanoma patients wit h advanced disease. (C) 2000 Lippincott Williams & Wilkins.