Evaluation of the clinical usefulness of measuring urinary excretion of 5-S-cysteinyldopa in melanoma: ten years' experience of 50 patients.

The urinary excretion of 5-S-cysteinyldopa (5-S-CD) is known to be increased in certain patients with melanoma. To evaluate its diagnostic and prognostic utility, we measured the urinary excretion of 5-S-CD on at least three different occasions in 50 patients with melanoma. No significant increase was found in 26 patients without metastases, in 10 patients with regional lymph node metastasis and 2 patients with amelanotic melanoma. However, all the 12 patients with distant metastases demonstrated a significant increase. The patients with 5-S-CD > 1,000 micrograms/day survived for a mean of 8.1 +/- 5.6 months, while those with 5-S-CD > 10,000 micrograms/day survived for 3.5 +/- 3.7 months. All the 4 patients with a maximum excretion of 5-S-CD > 40,000 micrograms/day had multiple liver metastases. In conclusion, while data on the urinary excretion of 5-S-CD was not useful in the detection of early regional lymph node metastases, its increase indicated the presence of distant metastases and also provided prognostic information.