pT1 clear cell renal cell carcinoma: a study of the association between MIB-1 proliferative activity and pathologic features and cancer specific survival.
BACKGROUND
The majority of patients with pT1 clear cell renal cell carcinoma (RCC) are cured with nephrectomy. However, a few patients will die of RCC. In several studies, MIB-1 proliferative activity was identified as an independent predictor of survival in patients with RCC. The objective of the current study was to examine MIB-1 proliferative activity in a large series of patients with pT1 clear cell RCC who were treated uniformly with radical nephrectomy, and to examine the association between proliferative activity and cancer specific survival in a multivariate model incorporating tumor size, nuclear grade, and tumor necrosis.


METHODS
Patients with solitary pT1 clear cell RCC who underwent radical nephrectomy between 1970-1997 were eligible for the current study. For each of the 40 patients who died of RCC, a stratified random sample of at least 3 year-matched patients who still were alive or had died of other causes at the time of last follow-up was selected. Patient age at nephrectomy, patient gender, tumor size, nuclear grade, and tumor necrosis were evaluated, and the MIB-1 proliferative activity was assessed using digital image analysis. Univariate and multivariate Cox proportional hazards models were fit to assess the features associated with cancer specific survival. The associations between MIB-1 proliferative activity and pathologic features were assessed using the Wilcoxon rank sum test.


RESULTS
The mean MIB-1 value for those patients who died of clear cell RCC was 6.5% compared with 3.6% for those patients who died of other causes or were still alive at the time of last follow-up. Patients whose tumor had an MIB-1 proliferative activity > o r = 5.0% were more than twice as likely to die of RCC than patients whose tumors had a MIB-1 activity < 5% (P = 0.02). However, after adjusting for tumor size, nuclear grade, and necrosis, MIB-1 proliferative activity was not found to be associated significantly with cancer specific survival. There was a significant association between MIB-1 proliferative activity and tumor size, nuclear grade, and necrosis.


CONCLUSIONS
After adjusting for tumor size, nuclear grade, and necrosis, MIB-1 proliferative activity was not found to be an independent predictor of outcome in patients with pT1 clear cell RCC who were treated with radical nephrectomy. There was a significant association between MIB-1 and other well established pathologic prognostic features of pT1 clear cell RCC.
Cheville
John C
JC
Department of Pathology and Laboratory Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA. cheville.john@mayo.edu
Zincke
Horst
H
Lohse
Christine M
CM
Sebo
Thomas J
TJ
Riehle
Darren
D
Weaver
Amy L
AL
Blute
Michael L
ML
D000911:Antibodies, Monoclonal; D034961:Antigens, Nuclear; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002292:Carcinoma, Renal Cell / Q000378:metabolism* / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D002455:Cell Division; D015331:Cohort Studies; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D019394:Ki-67 Antigen; D007680:Kidney Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D009336:Necrosis; D009367:Neoplasm Staging; D009392:Nephrectomy; D009687:Nuclear Proteins / Q000378:metabolism*; D011379:Prognosis; D015996:Survival Rate; D013997:Time Factors
D000911:Antibodies, Monoclonal; D034961:Antigens, Nuclear; D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen; D009687:Nuclear Proteins