Bax to Bcl-2 ratio and Ki-67 index are useful predictors of neoadjuvant chemoradiation therapy in bladder cancer.

OBJECTIVE: In this study, locally advanced bladder cancer was treated by radiation combined with cisplatin therapy and a retrospective analysis was conducted to predict the clinical response to chemoradiotherapy (CRT) based on the immunohistochemistry of apoptosis-related proteins.

METHODS: Sixty-two patients (median age, 68 years; range, 45-89 years) with transitional cell carcinoma of the bladder (pT1G3-pT4M0) treated with CRT (median dose: 40.5 Gy of radiation and 230 mg of cisplatin) were studied. Mucosal biopsy was performed before and after CRT. Paraffin-embedded tumor specimens were examined with TUNEL and were immunostained for Ki-67, p53, Bcl-2 and Bax; the Bax/Bcl-2 ratio and apoptosis index (AI) were calculated. Clinical features of the patients and response to CRT were compared with data obtained from examination of the tumors.

RESULTS: The 62 patients had a median follow-up period of 34 months (range, 3-84 months). Responses to CRT were as follows: CR, 34%; PR, 45%; NC, 21%. The survival rate of patients with Ki-67-positive tumors was significantly lower than those of patients with Ki-67-negative tumors (P < 0.05). No significant correlation was observed between the expression of any protein, the AI and the clinical response. However, the Bax/Bcl-2 ratio showed a significant association with the CR rate (P = 0.0289).

CONCLUSIONS: The results of this study suggest that the combined assessment of Bcl-2 and Bax protein expression may be used to predict a clinical response to CRT based on the Bax/Bcl-2 ratio determined before therapy. The Ki-67 index may be a useful predictor of prognosis in patients treated by CRT.