PREDICTION OF TUMOR-CONTROL IN PATIENTS WITH CERVICAL-CANCER - ANALYSIS OF COMBINED VOLUME AND DYNAMIC ENHANCEMENT PATTERN BY MR-IMAGING

OBJECTIVE. Quantitative analysis of either tumor volume or dynamic enh ancement pattern using MR imaging has been reported as useful in the p rediction of response to radiation therapy in cancer of the cervix. Be cause data for both analyses can be obtained in a single MR examinatio n, the purpose of this study was to evaluate whether combining both an alyses can further improve the efficacy of using MR imaging to predict tumor control after radiation therapy, MATERIALS AND METHODS. Twenty patients with bulky carcinomas of the cervix, stages bulky 1B (n = 2), IIB (n = 6), UTA (n = 1), IIIB (n = 9), IVA (n = 1), and recurrent (n = 1), were studied. Initial tumor volumes were calculated by outlinin g the area of tumor in each slice on T2-weighted images and multiplyin g by the slice profile. Two dynamic contrast-enhanced MR studies were obtained in each patient immediately before the start of radiation the rapy and after 20-22 Gy in 2 weeks of radiation therapy, Dynamic enhan cement imaging was performed at 3-sec intervals in the sagittal plane for 120 sec after rapid (9 ml/sec) IV injection of MR contrast agent ( 0.1 mmol/kg of gadoteridol) using a power injector, Time and signal in tensity curves reflecting the relative signal intensity of contrast en hancement in the tumor region were generated, and the relative signal intensity of the tumor region during the early plateau phase was calcu lated. Median follow-up was 25 months (range, 11-35 months). RESULTS. The combined analysis did not improve the prediction rate of local rec urrence in small-sized tumors, which responded well to radiation thera py regardless of their dynamic enhancement pattern. However, the combi ned analysis did improve the prediction rate of local recurrence in in termediate-and large-sized tumors (75% and 80%, respectively) over ass essment by either volume analysis (33% and 60%, respectively) or dynam ic enhancement pattern analysis (64% and 64%, respectively), The combi ned analysis was most useful in intermediate-sized tumors (40-99 cm(3) ; 33% recurrence), significantly improving differentiation between hig h-risk (80% recurrence) and low-risk (0% recurrence) patients (p = .01 0). CONCLUSION, Our preliminary results suggest that the combined data of both tumor morphologic (volume) and microcirculatory (dynamic enha ncement pattern) parameters allow more accurate prediction of local fa ilure in patients with advanced cervical cancer than does each individ ual parameter alone. Combined data appear to have the greatest potenti al in patients with intermediate-sized turners, who constitute most pa tients (60%) and remain a challenge for outcome prediction and managem ent.