Predictive value of Ki-67 expression confirmed in patients with bladder cancer

NEW YORK (Reuters Health) - Ki-67 expression is strongly predictive of increased risk for disease progression in patients treated with radical cystectomy for bladder urothelial carcinoma, according to findings published in the January 21st issue of the Journal of the National Cancer Institute.

"We showed previously," Dr. Shahrokh F. Shariat, of Memorial Sloan-Kettering Cancer Center, New York, and colleagues write, "in a cohort of 226 consecutive patients treated with radical cystectomy at a single academic center, that high Ki-67 labeling index was independently associated with disease recurrence and bladder cancer-specific mortality."

The researchers sought to validate their previous findings by assessing Ki-67 expression in tumor tissue from 713 patients treated with radical cystectomy and bilateral lymphadenectomy at six institutions. The team defined Ki-67 as being positive when samples demonstrated 20% or greater reactivity.

Among the 713 patients, bladder cancer recurred in 318 (44.6%). A total of 395 patients (55.4%) had died at the time of the analysis, 274 (38.4%) from metastatic bladder cancer.

An independent association was observed between Ki-67 overexpression and disease recurrence. A high Ki-67 labeling index was also associated with bladder cancer-specific mortality.

"We found that addition of the Ki-67 status to a standard multivariable model, which included tumor stage, grade, nodal status, and the presence of lymphovascular invasion, enhanced its predictive accuracy by 2.9% for disease recurrence and 2.4% for cancer-specific survival," Dr. Shariat and colleagues report.

Routine determination Ki-67 expression status "has the potential to improve identification of patients who are at increased risk for disease progression after radical cystectomy and thus may benefit from perioperative systemic chemotherapy," the team concludes.

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