Fewer tumour draining sentinel nodes in patients with progressing muscle invasive bladder cancer, after neoadjuvant chemotherapy and radical cystectomy

Sentinel Lymph Node Techniques in Urologic Oncology: Current Knowledge and Application

Lymph node (LN) metastases have a significant negative impact on the prognosis of urological malignancies. Unfortunately, current imaging modalities are insufficient when it comes to detecting micrometastases; thus, surgical LN removal is commonly used. However, there is still no established ideal lymph node dissection (LND) template, leading to unnecessary invasive staging and the possibility of missing LN metastases located outside the standard template. To address this issue, the sentinel lymph node (SLN) concept has been proposed. This technique involves identifying and removing the first group of draining LNs, which can accurately stage cancer. While successful in breast cancer and melanoma, the SLN technique in urologic oncology is still considered experimental due to high false-negative rates and lack of data in prostate, bladder, and kidney cancer. Nevertheless, the development of new tracers, imaging modalities, and surgical techniques may improve the potential of the SLN procedures in urological oncology. In this review, we aim to discuss the current knowledge and future contributions of the SLN procedure in the management of urological malignancies.

A prospective multicenter study of visual response-evaluation by cystoscopy in patients undergoing neoadjuvant chemotherapy for muscle invasive urinary bladder cancer

PURPOSE

To evaluate a method of transurethral visual response-staging in patients with urothelial muscle-invasive urinary bladder cancer (MIBC), undergoing neoadjuvant chemotherapy (NAC) and radical cystectomy (RC).

METHODS

A prospective study at four Swedish cystectomy centers, cystoscopy was performed after final NAC-cycle for MIBC. Fifty-six participants underwent cystoscopy for visual staging of the tumor immediately pre-RC. Visual assessments were correlated to pathoanatomical outcomes post-RC.

RESULTS

Seventeen tumors were classified as complete response (CR), i.e. pT0. Twenty-five patients had residual MIBC and 14 had non-muscle invasive residual tumors (NMIBC). Of the 39 patients with residual tumor, 25 were correctly identified visually (64%). Eleven patients were pN+. The diagnostic accuracy of cystoscopy to correctly identify complete response or remaining tumor was 70% (CI = 56-81%) with a sensitivity of 64% (CI = 47-79%), specificity 82% (CI = 57-96%), PPV 89% (CI = 74-96%) and NPV 50% (CI =38-61%). Twenty-eight cystoscopy evaluations showed signs of residual tumors and 3/28 (11%) were false positive. In 4/14 patients assessed having residual NMIBC the estimates were correct, 8/14 had histopathological MIBC and 2/14 had CR. In 11/14 patients (79%), the suggested visual assessment of MIBC was correct, 2/14 had NMIBC and 1/14 had CR. Twenty-eight cystoscopies had negative findings, 14 were false negatives (50%), when cystoscopy falsely predicted pT0. Among them there were eight patients with pTa, pT1 or pTis and six MIBC-tumors. In 17 patients with histopathological pT0, 14 were correctly identified with cystoscopy (82%).

CONCLUSION

Cystoscopy after the final NAC-cycle cannot robustly differentiate between NAC-responders and non-responders. Visually, negative MIBC-status cannot be determined safely.

Occult lymph node metastases in patients without residual muscle-invasive bladder cancer at radical cystectomy with or without neoadjuvant chemotherapy: a nationwide study of 5417 patients

Purpose

Little is known about the prevalence of occult lymph node metastases (LNM) in muscle-invasive bladder cancer (MIBC) patients with pathological downstaging of the primary tumor. We aimed to estimate the prevalence of occult LNM in patients without residual MIBC at radical cystectomy (RC) with or without neoadjuvant chemotherapy (NAC) or neoadjuvant radiotherapy (NAR), and to assess overall survival (OS).

Methods

Patients with cT2-T4aN0M0 urothelial MIBC who underwent RC plus pelvic lymph node dissection (PLND) with curative intent between January 1995–December 2013 (retrospective Netherlands Cancer Registry (NCR) cohort) and November 2017–October 2019 (prospective NCR-BlaZIB cohort (acronym in Dutch: BlaaskankerZorg In Beeld; in English: Insight into bladder cancer care)) were identified from the nationwide NCR. The prevalence of occult LNM was calculated and OS of patients with <(y)pT2N0 vs. <(y)pT2N+ disease was estimated by the Kaplan–Meier method.

Results

In total, 4657 patients from the NCR cohort and 760 patients from the NCR-BlaZIB cohort were included. Of 1374 patients downstaged to  <(y)pT2, 4.3% (N = 59) had occult LNM 4.1% (N = 49) of patients with cT2-disease and 5.6% (N = 10) with cT3-4a-disease. This was 4.0% (N = 44) in patients without NAC or NAR, 4.5% (N = 10) in patients with NAC, and 13.5% (N = 5) in patients with NAR but number of patients treated with NAR and downstaged disease was small. The prevalence of  <(y)pT2N+ disease was 4.2% (N = 48) in the NCR cohort and 4.6% (N = 11) in the NCR-BlaZIB cohort. For patients with  <(y)pT2N+ and  <(y)pT2N0, median OS was 3.5 years (95% CI 2.5–8.9) versus 12.9 years (95% CI 11.7–14.0), respectively.

Conclusion

Occult LNM were found in 4.3% of patients with cT2-4aN0M0 MIBC with (near-) complete downstaging of the primary tumor following RC plus PLND. This was regardless of NAC or clinical T-stage. Patients with occult LNM showed considerable worse survival. These results can help in counseling patients for bladder-sparing treatments.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-021-03839-7.