Computed-tomography based scoring system predicts outcome for clinical lymph node-positive patients undergoing radical cystectomy

Abstract

Purpose: Contrast-enhanced CT scan is the standard staging modality for patients with bladder cancer undergoing radical cystectomy (RC). Involvement of lymph nodes (LN) determines prognosis of patients with bladder cancer. The detection of LN metastasis by CT scan is still insuffi cient. Therefore, we investigated various CT scan characteristics to predict lymph node ratio (LNR) and its impact on survival. Also, pre-operative CT scan characteristics might hold potential to risk stratify cN+ patients. Materials and Methods: We analyzed preoperative CT scans of patients undergoing RC in a tertiary high volume center. Retrospectively, local tumor stage and LN characteristics such as size, morphology (MLN) and number of loco-regional LN (NLN) were investigated and correlation to LNR and survival was analyzed. CT scan characteristics were used to develop a risk stratifi cation using Kaplan-Maier and multivariate analysis. Results: 764 cN0 and 166 cN+ patients with complete follow-up and imaging data were included in the study. Accuracy to detect LN metastasis and locally advanced tumor stage in CT scan was 72% and 62%. LN larger than 15mm in diameter were signifi cantly associated with higher LNR (p=0.002). Increased NLN correlated with decreased CSS and OS (p=0.001: p=0.002). Furthermore, CT scan based scoring system precisely differentiates low-risk and high-risk profi les to predict oncological outcome (p <0.001). Conclusion: In our study, solely LN size >15mm signifi cantly correlated with higher LNR. Identifi cation of increased loco-regional LN was associated with worse survival. For the fi rst time, precise risk stratifi cation based on computed-tomography fi ndings was developed to predict oncological outcome for clinical lymph node-positive patients undergoing RC.

Vascular Enlargement as a Predictor of Nodal Involvement in Bladder Cancer

“…Conversely, Caglic et al [ 31 ] suggest a cut-off of 8 mm for the short axis of the positive LN in bladder cancer, confirmed by the European Association of Urology (EAU) [ 6 ]. However, Eismann et al [ 35 ] used a cut-off of 15 mm without any significant correlation with the clinical outcomes (cancer-specific survival and overall survival). In the case series of Thoeny et al [ 7 ], 68/88 LNs had a short axis ≤ 3 mm, 13/88 had a short axis > 3 to 5 mm, 5/88 had a short axis > 5 to 8 mm, and 2/88 had a short axis > 8 mm.…”

Management of Bladder Cancer Patients with Clinical Evidence of Lymph Node Invasion (cN+)

“…This is probably one of the primal causes of low accuracy in detection of LNI, mainly due to the relative common presence of metastases in normal sized LNs [16]. As a solution, different additional criteria, such as LN shape, internal architecture, number of loco-regional LNs and utilization of new contrast agents were proposed [42,47]. However, they have not gained widespread use so far.…”

Management of Bladder Cancer Patients with Clinical Evidence of Lymph Node Invasion (cN+)

“…This is probably one of the primal causes of low accuracy in detecting LNI, mainly due to the relatively common presence of metastases in normal-sized LNs [ 17 ]. As a solution, additional criteria were proposed, such as LN shape, internal architecture, number of loco-regional LNs, and utilization of new contrast agents [ 37 , 38 ]. However, they have not gained widespread use so far.…”