Prognostic flow cytometric information in cervical squamous cell carcinoma: a multivariate analysis of 307 patients

In a prospective study of 307 patients with invasive squamous cell carcinoma of the uterine cervix, the prognostic impact of flow cytometric parameters (ploidy level and the fraction of S-phase cells) and clinical variables was evaluated using univariate and multivariate analyses (Cox model). Mean follow-up time as 39 (4-84) months. A total of 93 patients died from their disease during the follow-up. The S-phase fraction was evaluable in 242 cases. By means of univariate models, lethality rate was found to increase significantly with increasing age, postmenopausal status, advancing stage, and increasing S-phase fraction. In a multivariate analysis of the clinical variables of age, stage, and grade, only clinical stage was prognostic. The inclusion of ploidy level in the analysis gave no additive prognostic information. In a multivariate analysis including all variables mentioned above, stage was the strongest predictor of survival. S-phase fraction was significantly related to survival both when studied as a continuous variable (P = 0.006) and when studied as a categorized variable (10, 15, 20% as cutoff points), and in this special analysis ploidy level was of prognostic interest with a poorer survival for near-diploid cases. The outcome was poorer with increasing age. The prognostic impact of the S-phase fraction remained highly significant in separate analyses of the clinically interesting stages Ib-IIb (P less than 0.001). We conclude that measurement of the S-phase fraction is of prognostic interest and may be used for the identification of high-risk patients within a given stage, whereas ploidy level yields little information.