Ki-67 expression in stage III cervical squamous cell carcinoma and its correlation with sensitivity to chemoradiotherapy

Abstract

To investigate the expression of proliferating cell nuclear antigen (Ki-67) in stage III cervical squamous cell carcinoma (SCC) and its correlation with the effect of chemotherapy on sensitivity to radiotherapy. In 50 patients with stage III cervical squamous cell carcinoma (SCC), 25 patients were treated with radiotherapy and 25 patients were treated with chemoradiotherapy. The expression of Ki-67 in the biopsy specimens of cervical SCC was detected by immunohistochemistry at diagnosis and after 10 Gy radiotherapy. The correlation of Ki-67 positive cells percentage and chemotherapy with sensitivity to radiotherapy was analyzed. In 25 patients with more than 48% Ki-67 positive cells at diagnosis, the rate of complete response (CR) was 72.0% (18/25). In 25 patients with less than 48% Ki-67 positive cells at diagnosis, the CR rate was 40.0% (10/25), with a significant difference between them (P = 0.023). In 26 patients with more than 31% decrease of Ki-67 positive cells after 10 Gy radiotherapy, the CR rate was 84.6% (22/26). In 24 patients with less than 31% decrease of Ki-67 positive cells after 10 Gy radiotherapy, the CR rate was 25.0% (6/24), showing a significant difference between the two groups (P < 0.001). In the cases of Ki-67<48%, decrease of Ki-67 positive cells of chemoradiotherapy group after 10 Gy radiotherapy was significantly higher than that of the radiotherapy group (P = 0.023). In the cases of Ki-67 ≥ 48%, no difference in the decease of Ki-67 positive cells between the chemoradiotherapy and radiotherapy groups was found (P = 0.173). For the radiotherapy-sensitive patients with CR recently, the 2-year progression free survival (PFS) rate and overall survival (OS) rate were 85.7% and 92.9%, respectively, both were significantly higher than those of radiotherapy-insensitive patients (18.2% and 40.9%, P < 0.05 for both). In stage III cervical SCC, the expression of Ki-67 before and after treatment with 10 Gy radiotherapy may be used as a biomarker to predict tumor response to radiation, and guide the choice of therapeutic strategies. Yet, the effect of chemotherapy as a radiosensitizer is unconspicuous.