Introduction and objective
Renal mass biopsy (RMB) has been increasingly used as the initial management of small renal masses. However, little is known about whether surgical delay after the positive biopsy results increases the risk of upstaging for small renal cell carcinomas (RCCs).
Patients with clinical T1aN0M0 RCCs (≤4cm) diagnosed between 2010 and 2016 who underwent RMB and then partial nephrectomy (PN) or radical nephrectomy (RN) were identified from the National Cancer Database (NCDB). Surgical delay time (SDT) was defined as days between RMB and definitive surgical resection (PN or RN). SDT was categorized into five groups: 1-30 days, 31-60 days, 61-90 days, 91-120 days, and 121-180 days. Upstaging to pT3a was used as the primary outcome of interest. Positive surgical margin (PSM) was used as a secondary outcome and analyses were restricted to PN cohort only.
A total of 4,340 patients were included and 237 (5.5%) patients had pT3a upstaging. Of the 2,874 patients who had PN, PSM rate was 8.2%. pT3a upstaging and PSM rates stratified by SDT is shown in the Figure. Multivariable logistic regression showed that compared with SDT of 1-30 days, SDT of 31-60 days (odds ratio [OR]=1.04, P= 0.833), 61-90 days (OR=1.17, P= 0.481), and 91-120 days (OR=1.14, P= 0.631) were not associated with increased odds of pT3a upstaging. Patients with SDT of 121-180 days had a higher risk of pT3a upstaging (OR= 1.93, P=0.016). When STD was ≤ 120 days, multivariable logistic regression with SDT considered as a continuous variable showed increased SDT was also not associated with higher odds of pT3a upstaging (OR=1.002, P=0.461). In the PN cohort, multivariable logistic regressions showed no significant associations between SDT and PSM with SDT either considered as a categorical or continuous variable.
In this NCDB study, increased SDT from RMB to definitive surgical resection of cT1aN0M0 RCCs was not associated with worse oncologic outcomes within 120 days after the RMB but patients with SDT > 120 days might have increased risk of upstaging. These findings have significant implications for patient counseling regarding active surveillance, RMB, and definitive surgical resection for small renal masses.
Source of funding