Ki-67 staining index predicts distant metastasis and survival in locally advanced prostate cancer treated with radiotherapy: An analysis of patients in Radiation Therapy Oncology Group Protocol 86-10

Rile Li, Kateri Heydon, M. Elizabeth Hammond, David J. Grignon, Mack Roach, Harvey B. Wolkov, Howard M. Sandler, William U. Shipley, Alan Pollack

Research output: Contribution to journalArticle

78 Scopus citations

Abstract

Purpose: Proliferative activity defined by Ki-67 staining index (SI) has been correlated with progression and prognosis in a number of malignant tumors including prostate cancer. However, few studies have examined Ki-67 SI in pretreatment diagnostic material from patients treated with definitive radiotherapy. In a prior study, we found that a Ki-67 SI of >3.5% was associated with poorer patient outcome. The goals of this analysis were to validate the prognostic value of Ki-67 SI and this cut point. Experimental Design: Of 456 assessable patients in Radiation Therapy Oncology Group Protocol 86-10, diagnostic material from 108 patients was available for Ki-67 analysis using MIB-1 antibody. Sixty patients were treated with external beam radiotherapy (EBRT) alone, and 48 patients were treated with short-term androgen deprivation + EBRT. Median follow-up was 9 years for those living. The relationship of Ki-67 with distant metastasis (DM), disease-specific survival (DSS), and overall survival (OS) was examined. Results: The median Ki-67 SI was 7.1% (range, 0.2-45.5%). The 7.1% cut point was associated with DM and DSS; however, the 3.5% cut point was as strong a determinant and was the focus of this analysis. In Cox proportional hazards regression, Ki-67 SI was independently associated with DM and DSS. When the Ki-67 SI was independently associated with DM and DSS. When the Ki-67 SI was ≤3.5% and >3.5%, the 5-year risk of DM was 13.5% and 50.8% (P = 0.0005), respectively, and the 5-year risk of DSS was 97.3% and 67.7% (P = 0.0039), respectively. No association of Ki-67 SI with OS was observed. Conclusions: Higher Ki-67 SI was significantly associated with a greater risk of DM and DSS in locally advanced prostate cancer after definitive EBRT or AD + EBRT.

Original languageEnglish (US)
Pages (from-to)4118-4124
Number of pages7
JournalClinical Cancer Research
Volume10
Issue number12 I
DOIs
StatePublished - Jul 15 2004
Externally publishedYes

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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