Nuclear Shape Analysis for Assessment of Prognosis in Renal Cell Carcinoma

Abstract

Clinically localized renal cell carcinoma is cured by radical nephrectomy in 47% [stage T3a (II)] to 65% [stage T1, T2 (I)] of the patients. Local recurrence and metastatic disease probably result from undetectable microscopic metastases present at operation. Chemotherapy and immunotherapy may improve cure rates if administered adjuvantly. The outcome of individual patients who share surgical stage cannot be predicted reliably by tumor histology, pathological grading and/or nuclear deoxyribonucleic acid analysis. Two groups of 10 patients with clinically localized renal cell carcinoma were similar by sex distribution (5 men and 5 women), surgical stage (stages T1 in 1, T2 in 6 and T3a in 3 patients) and age (54.3 .+-. 15.2 standard deviation versus 55.8 .+-. 8.7 years). Group 1 had no recurrences with a minimum followup of 5 years and a mean followup of 10 years. Group 2 died of metastatic renal cell carcinoma after a mean of 5 years. All neoplastic areas of each paraffin-embedded operative specimen were randomly sampled and the nuclear perimeter of 150 cancerous cells was digitized. There were 25 shape descriptors calculated for each nucleus. All shape descriptors for each patient were described by 19 statistical tests. Nuclear perimeter and area as well as mean nuclear roundness factor failed to separate the 2 groups. Range median quartiles of ellipticities by Fourier analysis, coefficients of variation of chain code minimums and relative means of largest 10 convexity values produced greatest separation (Mann-Whitney-Wilcoxon test p less than 0.001, and varience normalized difference 3.21, 3.29 and 2.83, respectively). These descriptors normalized and summed provided near perfect separation (Mann-Whitney-Wilcoxon test p less than 0.001 and variance normalized difference 3.59). We developed a quantitative nuclear morphometric analysis system that permitted the correct assignment of outcome in 19 of 20 patients. Accurate prediction of prognosis in patients with clinically localized renal cell carcinoma by nuclear shape analysis may allow for selection of patients for adjuvant therapy who have clinically undetectable metastatic disease.