Introduction & Objectives
Recently, the EAU Guidelines Panel on Renal Cell Carcinoma (RCC) proposed a renewed classification for clinical TNM staging of patients with suspected RCC with the aim of improving decision-making regarding selection for non-surgical options (active surveillance and ablative therapies), especially for small renal masses. Yet, this proposal has not been validated. Aiming to provide insights to refine current decision-making schemes for patients with localized renal masses, in this study we sought to evaluate whether and how the newly-proposed TNM classification would have reclassified patients treated with surgery.
Materials & Methods
After Institutional Review Board approval, we retrospectively queried a multi-institutional database promoted by the EAU Young Academic Urologists (YAU) Renal Cancer working group to select patients with a single cT1-2N0M0 renal mass treated with either partial or radical nephrectomy at 13 referral centers worldwide from 2015 to 2022. Renal masses were classified according to the currently recommended 2017 TNM system (cT1a vs cT1b vs cT2a vs cT2b) and to the newly-proposed scheme (cT1a if £30 mm vs cT1b if 30-70 mm vs cT2 if >70 mm). Then, we focused on the distribution of clinical and pathological features in the cT1a population. The cohort was randomly split in two cohorts and each cohort was assigned either to the current TNM or the newly-proposed TNM.
Results
Overall, 8189 patients were included. Median age was 61years (IQR 52-70); 65.4% were male. cT stage distribution was as follows: cT1a 4902 (59.9%) patients, cT1b 2502 (30.6%), cT2a 586 (7.2) and cT2b 199 (2.4%). According to the newly proposed TNM, cT stage was as follows cT1a 4029 (49.2%), cT1b 3375 (41.2%) and cT2 785 (9.6%). Among cT1a patients, 873 (17.8%) were reclassified as cT1b. After random selection, 4094 patients were assigned to the current TNM vs 4095 to the newly-proposed. After selecting cT1a RCC, 2463 patients vs 1991 remained, respectively. No significant differences in terms of benign rates (13.2 vs 13.4%), histology type and grade at final pathology were reported between the two groups. However, a consistent and significant higher proportion of cT1a RCCs were upstaged to pT1b (15 vs 13.8%), pT2 (2.5 vs 1.7%) and pT3 (1.4 vs 1.1%) in the current TNM.
Conclusions
Our data demonstrate that both the current and the newly-proposed TNM correctly stratified patients with suspected localized RCC, especially those with small renal masses. Although no differences were observed in terms of benign/malignant and less/more aggressive tumors, the newly-proposed TNM classification had lower rates of upstage at final pathology. This observation suggests a better identification of “true” T1a RCCs for whom alternative to surgery may be safely considered and suggested to patients during shared decision-making.
