# Impact of timing of computed tomography staging and patient factors on the detection of ‘true’ cN+ bladder cancer

## TL;DR

This study finds that the timing of CT scans relative to bladder tumor surgery does not affect the accuracy of lymph node staging in bladder cancer patients.

## Contribution

The study is the first to show that lymphovascular invasion at TURBT is a strong predictor of lymph node metastasis in clinically node-positive bladder cancer.

## Key findings

- Timing of CT scans before or after TURBT does not impact staging accuracy for bladder cancer lymph nodes.
- Lymphovascular invasion at TURBT is strongly associated with pathological lymph node metastasis at radical cystectomy.
- About half of patients with clinically node-positive bladder cancer were found to have no lymph node metastasis at surgery.

## Abstract

To evaluate whether computed tomography (CT) scans should be performed before or after transurethral resection of bladder tumour (TURBT) for accurate lymph node staging in clinically lymph node‐positive bladder cancer (BCa). Additionally, to identify patient factors that can aid in predicting lymph node metastasis.

In this retrospective, multicentre study, we analysed patients with cN+ M0 BCa staged by CT and treated with upfront radical cystectomy (RC) and pelvic lymph node dissection. We stratified patients by the interval between TURBT and CT into three groups: (1) before TURBT; (2) within 30 days after TURBT; and (3) more than 30 days post‐TURBT. Staging accuracy, defined as concordance between clinical and pathological lymph node status, was evaluated. We utilised logistic regression analyses to identify patient factors, including the optimal timing of staging, in predicting pathological lymph node status at RC.

Among 183 patients with cN+ disease, 90 (49%) had pN0 disease at RC. Of these, 40, 36 and 14 were staged before TURBT, within 30 days after TURBT, and more than 30 days post‐TURBT, respectively (P = 0.2). Pathological downstaging was most common in cN1 (22%) and cN2 (20%) disease. The overall concordance rate was 23%. The timing of staging did not correlate with pathological lymph node status on logistic regression (all P > 0.05). Lymphovascular invasion (LVI) at TURBT was associated with pN status (odds ratio 4.25, confidence interval 2.02–9.34; P < 0.001) at RC.

Overall, we found no association between the timing of CT‐based staging and pathological lymph node metastases in cN+ BCa. The data suggest that performing a TURBT prior to staging does not increase the finding of false‐positive nodes on imaging. LVI was the only factor at the time of TURBT associated with pathological lymph node metastasis at RC. Limitations include the multicentre retrospective design and the inclusion of only patients with clinically node‐positive disease.