Tumor doubling times in metastatic malignant melanoma of the uvea - Tumor progression before and after treatment

Objective: To obtain estimates of growth rate of metastatic uveal melanoma to infer appropriate follow-up programs and to assess the impact of current chemoimmunotherapy regimens. Design: Retrospective case series. Participants: Of 70 consecutive patients diagnosed with metastatic uveal me lanoma from 1986 through 1998, 37 patients who attended regular follow-up a nd had measurable metastases were eligible for this study. Methods: Tumor doubling time (DT) was calculated by the Schwartz formula us ing three presumed sizes of metastasis at last negative follow-up. Di was c ompared according to tumor characteristics, and time of micrometastasis was estimated, Main Outcome Measures: Doubling time of untreated and treated metastases, Results: Doubling time of untreated metastases ranged from 34 to 220 days ( median, 63 days). Regardless of the presumed size of metastasis at last scr eening, two thirds of the metastases had a DT between 30 and 80 days. No si gnificant correlation between DT and the observed disease-free interval was detected. Assuming constant growth rate, most metastases had predictably i nitiated within 5 years before primary treatment. Mean DT during active tre atment of metastases in 18 patients who did not show an objective response ranged from 25 to 2619 days (median, 255 days). Conclusions: Based on the estimated growth rates, a rational follow-up inte rval to detect metastatic uveal melanoma would be 4 to 6 months. Primary uv eal melanomas that develop clinically detectable metastasis after conservat ive therapy may micrometastasize several years before treatment. These esti mates are rough and must be confirmed by prospective studies. Current chemo immunotherapy regimens slow down the growth rate of metastases even if obje ctive response is not obtained. Ophthalmology 2000;107:1443-1449 (C) 2000 b y the American Academy of Ophthalmology.