Calculated tumour volume as a prognostic parameter for survival in choroidal melanomas

Tumour diameter, tumour height, and tumour volume are considered important prognostic indicators of survival in choroidal melanomas. In this study, we investigated the prognostic impact on survival of the easily calculated volume estimate based on the assumption of a half-rotation ellipsoid.

The largest tumour diameter and tumour height were measured by ultrasound A- and B-scan in 93 patients with choroidal melanoma. Tumour volume was calculated by the half volume of a rotation ellipsoid formula, rotated around the y-axis, and compared to tumour diameter and tumour height. All parameters were correlated to the clinical outcome of the patients.

At the time of diagnosis, the mean diameter was 10.4 mm (range 4.1-18.9 mm), and the mean height was 5.7 mm (range 1.74-14.9 mm). The range of the calculated tumour volume was between 11 and 628 mm(3) (mean volume 190 mm(3)). Among all patients, distant metastases occurred in 10 patients (10.8%). In a univariate approach using Mantel-Haenszel log-rank test, the calculated tumour volume at the time of diagnosis was the best prognostic indicator of survival followed by tumour diameter and tumour height (P=0.028). When tumour volume, horizontal and vertical tumour diameter, age, sex, and primary tumour therapy were considered in a multivariate approach using Cox proportional Hazard model, only tumour volume turned out as a significant prognostic parameter (P=0.001).

Calculated tumour volume is a better prognostic indicator of survival of patients with choroidal melanomas than the largest tumour diameter and tumour height, and might be established in daily routine.