Clinical stage I carcinoma of the cervix: value of MR imaging in determining degree of invasiveness.

The depth of tumor invasion measured at histologic examination is the most important prognostic factor in early-stage carcinoma of the uterine cervix. The ability of MR to estimate the depth of tumor invasion was studied in 47 patients who subsequently underwent radical hysterectomy. In two patients, MR failed to detect tumors with infiltration depths of 2 and 4 mm. The maximum sagittal tumor length along the axis of the cervix (D) and the maximum tumor area on sagittal (S) and axial (A) images were measured with MR. The depth of tumor infiltration determined histologically (I) correlated with the degree of infiltration noted on MR images. The univariate correlation coefficients for log I vs log D, log S, and log A were .87, .84, and .77, respectively. By stepwise inclusion of the variables in a multivariate analysis, the contributions to the coefficient of determination from including log S and log A after log D were less than 1%. The regression analysis showed that the best estimate for the depth of invasion was close to half of the sagittal tumor length measured on MR, I = D/2. Our experience shows that MR is valuable in determining the degree of invasiveness in clinical stage I tumors.