Nuclear grading of primary pulmonary adenocarcinomas: correlation between nuclear size and prognosis.

BACKGROUND

According to the World Health Organization Classification of Tumors, the prognostic value of morphometric cytologic atypia has not been assessed in pulmonary adenocarcinoma.

METHODS

Primary tumors of 133 pulmonary adenocarcinomas <or=2 cm were analyzed using an image processor for analytical pathology. The results were evaluated using receiver operator characteristic curve analysis, and survival curves were drawn by the Kaplan-Meier method. Furthermore, the results were applied to routine histological diagnosis. Four pathologists evaluated the nuclear factors relative to the size of small lymphocytes as a standard.

RESULTS

By using the nuclear area and nuclear major axis dimension, lung adenocarcinomas were divisible into 2 groups showing extremely favorable prognosis and fairly favorable prognosis, without considering histological features or classification. A nuclear area level of <67 microm(2) was correlated with longer survival (P < .0001), and the 5-year survival rate was 90.4%. Similarly, a nuclear diameter level of <0.7 microm was correlated with longer survival (P = .0002), and the 5-year survival rate was 88.6%. The mean (+/-standard deviation [SD]) value of the kappa statistic for the 4 pathologists who evaluated the cases using the size of small lymphocytes as a standard was 0.58 +/- 0.10, and the mean (+/-SD) value of the accuracy metric was 0.66 +/- 0.10.

CONCLUSIONS

Nuclear area and nuclear major dimension are 2 useful independent markers for evaluating the prognosis of lung adenocarcinoma.