31P magnetic resonance spectroscopy of animal uveal melanoma.

Scleral surface coils were used to obtain in vivo magnetic resonance spectra (MRS) of Greene melanoma implanted in the rabbit uvea. Well-localized tumor spectra (4.7 Tesla) with good signal-to-noise ratios (S/N) were obtained from the tumor with a "single-pulse" sequence in less than 1 hour. Tumor localization was confirmed with one-dimensional spectroscopic imaging studies. Serial 31P spectra were obtained during tumor growth and after both optimal and suboptimal hyperthermia. Early 31P MRS change is correlated with tumor treatment response and preceded histologic evidence of cell destruction. Twenty-four to 48 hours after successful treatment, the inorganic phosphate/nucleoside triphosphate (NTP), and phosphomonoester/NTP ratios were significantly increased from 1.2 +/- 0.1 to 1.7 +/- 0.1 and 1.3 +/- 0.1 to 1.8 +/- 0.2, respectively. In contrast, untreated or ineffectively treated tumors showed little change. Interpretation of 31P MRS data in this animal uveal melanoma model after the first week was complicated by decreased S/N, increased contamination from contiguous tissues, ingrowth of fibroblasts, macrophages, and intratumor hemorrhage.

Bromodeoxyuridine uptake in the assessment of hyperthermic therapy for intraocular tumor.

Assessment of uveal melanoma response after many nonenucleation therapies is difficult with current modalities, since tumor regression is usually delayed. The goal of most treatments, including ionizing radiation or radiation and adjunct hyperthermia, is to destroy the reproductive capacity of the tumor. Cell cycling analysis with bromodeoxyuridine, a thymidine analogue only incorporated during DNA synthesis, was a useful indication of tumor control after hyperthermia was used to treat a Greene intraocular melanoma model. Cell cycling decreased from a mean of 16% before therapy to less than 1% in all the successfully treated tumors. Cell cycling changes preceded histologic evidence of cell death. In contrast, tumors that grew after insufficient treatment had increased cell cycling to a mean of 25%. Cell cycling studies with bromodeoxyuridine represent a sensitive gauge of the reproductive integrity of the tumor.

Effect of various doses of radiation for uveal melanoma on regression, visual acuity, complications, and survival.

We reviewed 284 choroidal and ciliary body melanomas treated with 50, 60, 70, or 80 gray equivalents (GyE) of helium ion radiation. Multivariate methods of data analysis were used to adjust for differences between dose groups with respect to the characteristics of patients (and their tumors). Radiation dose level did not affect survival, complications, visual outcome, or tumor regression in this model. The minimum radiation dose necessary to achieve tumor control with charged particles may be less than 50 GyE.

Coincident systemic malignant disease in uveal melanoma patients.

Differentiation of a primary uveal melanoma from a uveal metastasis can be difficult. Review of the records of 627 patients with choroidal or ciliary body melanoma seen at our institution between September 1977 and November 1987 showed that 53 (8%) had a second, systemic malignant disorder. A complete ophthalmologic evaluation, including indirect ophthalmoscopy, fundus photography, ultrasonography and general medical studies, should minimize incorrect ocular diagnosis and inappropriate therapy.