Study Type – Prognosis (case series)
Level of Evidence 4
What's known on the subject? and What does the study add?
We had known from former studies of RCC that the risks of high grade tumours increased with tumour size and probability of localized tumour decreased with tumour size increasing. Our study had provided large and detailed data about pathologic features of RCC. We also examined the exactly changing of probabilities of different subtypes with diameter increasing and evaluated the effects of hemorrhage, necrosis and cystic degeneration on pathologic subtypes.
- • To investigate the correlation between tumour size and histopathological characteristics of renal cell carcinoma (RCC).
PATIENTS AND METHODS
- • A total of 1867 patients who underwent surgical operation between January 2002 and March 2010 due to RCC were included. According to 1997 WHO recommendation about Fuhrman nuclear grading of RCC which criteria we used, tumours were stratified by the largest pathologic diameter into 5 groups, the discrepancy of tumour grade between different groups and whether tumour size could predict histological subtype were analyzed.
- • The largest diameter (mean ±sd) of G1, G2, and G3 tumours were 3.27 ± 1.46 cm,4.87 ± 2.23 cm, and 7.39 ± 3.11 cm, respectively. The percentage of extracapsular extension tumours in 2 cm or less, 2.1 and 4.0 cm, 4.1 to 7 cm, 7.1 to 10 cm, and more than 10 cm group were 0.5%, 4.3%, 19.8%, 57.9%, and 91.9%, respectively. The distribution of G1 tumours shows a decreasing trend with the diameter becoming larger, while the G3 tumours shows an opposite trend (P < 0.05). Logistic regression analysis predicted that the odds of papillary, chromophobe, and other types vs clear cell decreased with increase in tumour size. If the tumour was complicated with hemorrhage or necrosis, the chance of being chromophobe was higher, while the probability of being papillary and chromophobe decreased when a tumour with cystic degeneration.
- • There was a significant correlation between tumour size and tumour grade and stage; Larger tumours were prone to have higher grade and stage, and the probability of being clear cell carcinoma grew higher as the tumour size increased.