The role of Ki67 proliferation assessment in predicting local control in bladder cancer patients treated by radical radiation therapy.
OBJECTIVE
To assess whether tumour proliferation as measured by Ki67 immunostaining has any predictive value for local control in bladder cancer patients treated by radiotherapy.


METHODS
Fifty-five patients suffering from infiltrating bladder carcinoma recommended for radical radiotherapy (66 Gy/6-7 weeks) were included in this study. Paraffin-embedded pre-treatment tumour sections were stained with the Ki67 antibody. The percentage of Ki67-positive nuclei was correlated with established prognostic factors, local control and survival.


RESULTS
The Ki67 index was not related to local control in our patients when the median was selected as the cut-off value. Patients with tumours with a very low (<27%) Ki67 index had better local control at 5 years (69%) than patients with tumours with greater (>27%) Ki67 expression indices (31.5%) (P<0.05; log-rank test).


CONCLUSIONS
Ki67 immunostaining was a feasible method to estimate tumour proliferation. Patients with very low proliferating tumours seemed to achieve better local control after fractionated radiotherapy compared to other patients. Further studies are needed with a greater number of patients to accurately define the role of Ki67 expression in predicting tumour repopulation during fractionated radiotherapy.
Department of Radiation Oncology, Hospital Nuestra Señora del Pino, Las Palmas de Gran Canaria, Spain.
P C
PC
Lara
A
A
Rey
C
C
Santana
J L
JL
Afonso
J M
JM
Diaz
G J
GJ
González
R
R
Apolinario
D014408:Biomarkers, Tumor / Q000097:blood; D002295:Carcinoma, Transitional Cell / Q000097:blood / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D002455:Cell Division / Q000528:radiation effects; D005500:Follow-Up Studies; D006801:Humans; D019394:Ki-67 Antigen / Q000096:biosynthesis / Q000097:blood*; D015588:Observer Variation; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D001749:Urinary Bladder Neoplasms / Q000097:blood / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen