Coefficient of variation of nuclear diameters as a prognostic factor in papillary thyroid carcinoma

To determine whether the coefficient of variation (CV) of nuclear diameters can be used as a prognostic factor in papillary thyroid carcinoma, we reviewed fine needle aspiration smears with Riu's stain from 55 operated-on and pathologically verified cases with a median follow-up of 6.5 years. For each case we measured the nuclear diameters of 100 cancer cells by ocular micrometry and calculated the CV of the nuclear diameters. Then we correlated the CV with the clinical stage, recurrence and death. There was a positive correlation between the CV of the nuclear diameters and the clinical stage (r = .59, P less than .0001). Recurrent cases (n = 10) had a higher CV than did those without recurrence (n = 45) (18.04 +/- 4.1% [mean +/- SD] versus 13.2 +/- 2.7%, P less than .0005). All recurrent cases had a CV greater than 13%. The cases in which death occurred (n = 5) had a higher CV than did those with survival (n = 50) (20.1 +/- 4.9% versus 13.5 +/- 2.7%, P less than .0005). All cases in which death occurred had a CV greater than 15%. The extent of variation of nuclear diameters was one of the factors influencing prognosis in papillary thyroid carcinoma. It offers a prognostic adjunct to standard clinical and histologic analysis.