Clinical staging accuracy of renal tumors

Objective: To evaluate the reliability of measurements obtained using standard imaging techniques (ultrasound and CT scan) vs pathological measurements and the relationship between clinical staging and the choice of the type of surgery. We also analyzed the relationship between cancer parameters (size, site, type of surgery) and prognosis. Materials and Methods: A retrospective analysis was conducted to examine a series of 140 patients with kidney cancer, all of whom underwent preoperative staging with abdominal ultrasound scan US and CT scan. To assess agreement between US and CT measurements and the pathologic size of renal tumors, we calculated the mean difference between the techniques, Pearson’s correlation coefficient and Bland-Altman test. Results: The comparison between imaging and pathological findings revealed a good classification of tumor dimensions between the two imaging methods and pathologic size (correlation coefficients all over 0.8), and with limits of agreement of ± 2.2 cm for US measurement and of ± 2.3 cm for CT measure. We observed that the range in which the measurement error is lowest is over 6 cm: in other words, when smaller lesions are present there is a greater likelihood of committing measurement errors. As expected, logistic regression analysis shows that the size of the tumors significantly influenced the surgical approach and survival at five years follow-up. Conclusions: The imaging methods used in clinical staging of renal tumors currently allow us to select the most appropriate surgical option with a certain amount of confidence. Tumor size continues to be one of the most important factors in prognosis and it can influence both the surgical approach and cancer-specific survival.