Influence of tumor size on oncological outcomes of pathological T3aN0M0 renal cell carcinoma treated by radical nephrectomy
March
Influence of tumor size on oncological outcomes of pathological T3aN0M0 renal cell carcinoma treated by radical nephrectomy
Luyao Chen 0 1
Xin Ma 0 1
Hongzhao Li 0 1
Liangyou Gu 0 1
Xintao Li 0 1
Yu Gao 0 1
Yongpeng Xie 0 1
Xu Zhang 0 1
0 State Key Laboratory of Kidney Diseases, Department of Urology, Chinese PLA General Hospital , Beijing, China, 2 Medical School, Nankai University , Tianjin , China
1 Editor: Renato Franco, Seconda Universita degli Studi di Napoli , ITALY
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Data Availability Statement: All relevant data are
within the paper and its Supporting Information
files.
Funding: The authors received no specific funding
for this work.
Competing interests: The authors have declared
that no competing interests exist.
Objective
To evaluate the prognostic significance of tumor size in pathological T3aN0M0 renal cell carcinoma (RCC) treated by radical nephrectomy.
Materials and methods
Patients who underwent radical nephrectomy for sporadic RCC with pathological T3aN0M0
RCC at our institution between January 2006 and June 2015 were identified. The entire
cohort was divided into two groups according to the cutoff of tumor size obtained from
receiver operating characteristic (ROC) curve. Clinicopathological variables were
retrospectively collected and compared. Kaplan-Meier analysis and multivariate Cox regression were
conducted to evaluate the effect of tumor size on survival outcomes.
Results
163 pT3aN0M0 RCC patients were included with a median follow-up period of 31 months.
The optimal cutoff for tumor size was 7 cm according to the ROC curve. 90 cases (55.2%)
presented tumors which measured 7 cm or less, and 73 cases (44.8%) showed tumor size
greater than 7 cm. Patients with larger tumors tended to exhibit higher rates of symptoms
and higher Fuhrman grades; they also indicated more necrosis features, and were more
likely to invade the collecting system and renal vein. Compared with patients who exhibited
tumor size of 7 cm, those with tumor size>7 cm were associated with shorter estimated
five-year cancer-specific survival (CSS, 46.6% versus 75.0%, P = 0.003) and five-year
recurrence-free survival (RFS, 35.6% versus 62.7%, P = 0.011). Multivariate Cox analysis
revealed that tumor size was retained as an independent factor for CSS (HR = 2.506, 95%
CI 1.169±5.373, P = 0.018).
Conclusions
The tumor size significantly affected the survival outcomes of pT3aN0M0 RCC treated by radical nephrectomy, and a cutoff size of 7 cm can help enhance the prognostic
discrimination. Thus, the tumor size may be considered in the future TNM classification
of stage pT3a.
Introduction
Renal cell carcinoma (RCC), which is the third most common urologic tumor, accounts for
approximately 3% of all reported human cancers worldwide [
1
]. With approximately 20%±
30% of patient relapse after surgical resection [
2
], RCC patients should be closely followed up
and stratified into categories with different recurrence and survival risks. The currently most
useful determinant of RCC classification is the tumor, node, and metastasis (TNM) staging
system [
3
], which provides critical prognostic and therapeutic information for patients. This
golden standard system has been revised in recent decades to improve its prognostic accuracy
and predictive ability [
4, 5
]. According to the latest AJCC 2010 TNM system[6], pathologic
stage T1 and T2 RCC are classified depending solely on tumor size ( 7 cm for T1 and >7 cm
for T2), whereas T3a is defined on the basis of anatomic tumor extension including vein or fat
invasion, regardless of tumor size. Consequently, the neglected results in small and large
masses are classified together, which may indicate further T3a classification modification.
The tumor size has been demonstrated as a very important prognostic factor among RCC
patients [7±9]; however, the prognostic effect of tumor size in stage T3a has attracted relatively
minimal attention in past studies. In 2007, Lam et al. [
10
] performed a retrospective analysis of
623 T3a RCC cases and concluded that the tumor size is an important predictor of
cancer-specific outcomes among T3a RCC patients with fat invasion alone. Recently Suer et al. [
11
] also
found that pT3a tumors larger than 7 cm demonstrated the worse prognosis compared to
other smaller tumors after a retrospectively review of 338 consecutive patients with
pT13aN0M0 RCC, involving 63 pT3a tumors,. These interesting findings indicate that the
prognostic role of tumor size may apply to not only low (T1 and T2) but also high (T3a) tumor
stages.
In the present study, we retrospectively analyzed the records of pT3aN0M0 RCC patients in
the database of our institution. We also evaluated the significance of tumor size by assessing its
effect on patient survival outcomes and its association with other clinicopathological factors.
Materials and methods
Patient selection and data collection
After obtaining approval from the ethical committee of t (...truncated)