The prognostic value of semiquantitative nuclear grading in endometrial carcinomas.

The objective of this study was to evaluate the prognostic value of a convenient nuclear grading system based on only the proportion of nuclei measuring more than 10 microm in length at the shortest axis in endometrial carcinomas. Of the 235 cases reviewed, 9 serous and 5 clear cell adenocarcinomas and 2 small cell carcinomas were eliminated, resulting in a study population of 219 cases of endometrial adenocarcinoma. The architectural grade was determined by the FIGO system. The criteria for nuclear grade were as follows: grade 1, no nucleus measuring more than 10 microm in length at the shortest axis; grade 2, nuclei measuring more than 10 microm in length at the shortest axis seen in percentages ranging between 0 and 10% of tumor cells in active areas; and grade 3, more than 10% of tumor cells in active areas with nuclei measuring more than 10 microm in length at the shortest axis. The criteria for combined grades were as follows: the tumors were graded according to the architectural grade, but high-grade nuclear abnormalities increased the grade by one for architectural grade 1 and 2 tumors. The cumulative 10-year survival rates for architectural grades 1, 2, and 3 were 92.4, 82.6, and 65.2%, respectively (chi2 = 17.9, P = 0.001). The survival rates for nuclear grades 1, 2, and 3 were 96.2, 76.1, and 70.1%, respectively (chi2 = 21.6, P < 0.001), while for combined grades 1, 2, and 3 the survival rates were 98.3, 83.2, and 65.2%, respectively (chi2 = 26.9, P < 0.001). Even when the cases were limited to the 147 stage I endometrial carcinomas examined, the prognostic value of the combined grading system was still found to be superior to that of the architectural grading system. Our observations therefore supported the FIGO recommendation for nuclear grade not only in stage I endometrial carcinomas, but also in all stages of endometrial carcinomas.