Hp. Kujari et al., USE OF THE MITOTIC COUNTS FOR THE PROGNOSIS AND GRADING OF BREAST-CANCER - METHOD EVALUATION STUDY, Pathology research and practice, 190(6), 1994, pp. 593-599
Reproducibility of the volume fraction-corrected mitotic index (M/V(V)
index) was studied in 144 unselected breast cancer specimens. The inf
luence on decision making of variation in determining the index was al
so analysed. - In the complete series of specimens the correlation bet
ween two observers, one subjectively estimating the epithelial fractio
n of tumor epithelium and the other using point-counting (10 x 10 ocul
ar grid), was good (Pearson's r = 0.82, p < 0.001, 95% CI 0.70-0.92).
- A subset of 30 specimens was used to evaluate the grading efficiency
(GE) of the M/V(V) index method. The mean grading efficiency as estim
ated from this subset varied between 90% and 93%. The average minimum
GE value was 82.8% (SD = 3.4%). The findings suggest that when the M/V
(V) index method is used, the grading is correct on average in 90% or
more of the cases, but dependant on the cutoff point. The over-all gra
ding efficiency of the M/V(V) index method was at least 85% at all cut
points in both series. The GE-value of the M/V(V) index method was com
parable to that obtained from published S-phase fraction data on breas
t cancer specimens from three independed laboratories. We conclude tha
t the M/V(V) index in breast cancer analysis is a sufficiently reprodu
cible method in mitosis counting, and that it can be used with subject
ive or point count estimation of the area fraction of neoplastic epith
elium.