[How accurate is the correlation between clinical and pathological TNM stages in renal tumours?]

In clinical practice the tumour size measured in the histopathological examination of the operative specimen is used both to determine tumour stage. We have investigated the agreement between tumour size determined by preoperative computed tomography (CT) and pathological tumour size.

Between 2000 and 2007 a total of 444 consecutive patients was diagnosed with a renal tumour and treated operatively at our clinic. A total of 276 patients was eligible and thus included in the study.

There were 62% men and 38% women with a median age of 65 years. There were 255 renal cell carcinomas, 7 oncocytomas, 3 angiomyolipomas, and 11 tumours of other histology. Mean tumour size was 65 mm in preoperative radiographic estimates and thereby a mean of 3 mm smaller than the mean pathological tumour size (62 mm, p = 0.0000066). In the radiographic estimate only 67% of the tumours were in the range of a 1 cm size difference of the postoperatively determined tumour size and in only 53% of the cases did the clinical and pathological TNM stages match. In 28/276 cases (10%) the clinical tumour stage was ≥ T2 but the histopathological examination showed a pTNM stage < T2.

Different tomographs as well as observers are probably the main causes for the present results. Standardisation should be established to provide an accurate basis for a differentiated discussion about therapeutic options. This is especially true for low tumour stages where tumour size is the only criterion for staging.