Nisen et al reported the Renal Tumor Invasion Index (RTII) for evaluating a patient with a renal tumor prior to partial nephrectomy. The index is associated with postoperative complications. The authors are from Helsinki University Central Hospital and the University of Helsinki.
Patient selection: renal tumor, being evaluated for partial nephrectomy
Parameters:
(1) tumor invasion depth in cm (distance from the deepest point of tumor invasion to where the surface would be if there was no tumor)
(2) parenchymal thickness just next to the tumor in cm
renal tumor invasion index =
= (invasion depth) / (parenchymal thickness)
Interpretation:
• The maximum RTII is given as 3.8 in Figure 2.
• Most patients have an RTI <= 1.2.
• The higher the index the greater the risk of 30-day urological complications.
• Measurement of invasion depth needs to be standardized to prevent variation based on how the measurement is taken. The need is evident in Figure 1B.
Performance:
• The area under the ROC curve was 0.64.
