AbstractIn a prospective study involving 158 patients with carcinoma of the uterine cervix, DNA content, S‐phase fraction (SPF), and Ki‐67 proliferative index were evaluated in fresh tissue using flow cytometry and immunocytochemical analysis. Of all tumors, 57.1% were aneuploid. In this subgroup, 25% of tumors had a DNA index between 1.6 and 1.8. SPF values ranged from 0.5 to 57.2% and were significantly higher (P<0.0001) in tumors with an abnormal DNA content (aneuploid). Ki‐67 labeling index ranged from 1.7 to 65.0%. No association was found between any of the above‐mentioned parameters and clinical stage or histological type of tumor. When analyzing overall survival, a statistically significant difference was found between stage IIB patients with aneuploid and diploid DNA content. In 39 carcinomas evaluated after 1 week of radiotherapy, irradiation induced a significant decrease in Ki‐67 index. In 7 aneuploid tumors where cell cycle analysis was feasible, a significant increase in G2 + M phase fraction was observed (P<0.02). We suggest these parameters are therefore useful to monitor radiation‐induced alterations in cell cycle and proliferation. © 1995 Wil