Cutaneous and
uveal melanoma both have a poor prognosis and
chemotherapy is usually unsuccessful. We have previously reported the activity of a number of
cytotoxic agents against metastatic cutaneous and primary choroidal
uveal melanoma using an ex vivo
adenosine triphosphate (
ATP)-based chemosensitivity assay (
ATP-TCA). In this study we compare the results obtained with the two types of
melanoma. Cutaneous
melanoma deposits in skin and lymph nodes (n = 58) and choroidal
melanomas (n = 77) were tested using the
ATP-TCA. Analysis of the data based on an arbitrary threshold for sensitivity shows that both types of
melanoma exhibit heterogeneity of sensitivity to all the agents and combinations tested. With all the single agents except
gemcitabine, cutaneous
melanomas showed greater sensitivity in the assay, though this did not achieve statistical significance. This was also true with the
drug combinations, with the exception of
treosulfan +
gemcitabine, which had similar activity in each type of
melanoma. Of all the single agents tested,
doxorubicin (47% of specimens classed as sensitive),
vinorelbine (43%),
treosulfan (41%) and
paclitaxel (33%) showed the greatest activity with cutaneous
melanoma. In the
uveal melanoma samples,
mitoxantrone (33%),
gemcitabine (22%) and
treosulfan (21%) showed the greatest activity. In contrast to the cutaneous
melanomas, 13% of the uveal
melanomas were sensitive to
paclitaxel, 4% were sensitive to
doxorubicin and 11% were found to be sensitive to
vinorelbine. Both tumour types showed greater sensitivity to combinations of
cytotoxic agents. The combination of
treosulfan +
gemcitabine was universally effective, with 72% of cutaneous
melanomas and 80% of uveal
melanomas exhibiting activity at the level selected to indicate sensitivity in the assay, though this will not necessarily indicate a similar level of clinical sensitivity.