Sentinel lymph node biopsy in muscle-invasive bladder cancer: single-center experience

Intra-operative lymphatic mapping and sentinel node biopsy in laryngeal carcinoma using radiotracer injection

OBJECTIVE

The purpose of this study was to determine the value of sentinel lymph node biopsy (SLNB) in the laryngeal SCC, using intra-operative peri-tumoral injection of Tc-99m-phytate.

METHODS

Patients with biopsy-proven squamous cell carcinoma of the larynx were included. On the day of surgery, after anesthesia induction, suspension laryngoscopy was performed to inject 74 MBq/0.4 ml Tc-99m-phytate in four aliquots into the sub-mucosal peri-tumoral location. After a 10-min wait, a portable gamma probe was used to locate sentinel nodes. Subsequently, all patients underwent laryngectomy and neck dissection. Both sentinel nodes and non-sentinel nodes were examined using hematoxylin and eosin (H&E) staining.

RESULTS

Twenty-six patients with a diagnosis of laryngeal carcinoma were included in the study. The SLN detection rate was 65.4%, with a 100% detection rate in the supraglottic region and a 52.6% detection rate for glottis/transglottic patients. Permanent pathology results showed lymph node involvement in four patients, but only one patient had a negative result in the SLNB, resulting in an overall false negative rate of 25%. The sensitivity of the SLN technique was 75% overall, 100% in the supraglottic region, and 67% in the glottis/transglottic region.

CONCLUSION

The accuracy and feasibility of SLNB may be related to the location of the tumors in the larynx. For supraglottic tumors, the technique seems to be feasible with a low false negative rate. For glottis/transglottic tumors, both the detection rate and false negative rate seem to be suboptimal. Further studies are needed to validate our results.

Near-infrared fluorescence lymph node template region dissection plus backup lymphadenectomy in open radical cystectomy for bladder cancer using an innovative handheld device: A single center experience

BACKGROUND

The extent of pelvic lymphadenectomy (PLND) as part of radical cystectomy (RC) for bladder cancer (BC) remains unclear. Sentinel-based and lymphangiographic approaches could lead to reduced morbidity without sacrificing oncologic safety.

OBJECTIVE

To evaluate the feasibility and diagnostic value of fluorescence-guided template sentinel region dissection (FTD) using a handheld near-infrared fluorescence (NIRF) camera in open radical cystectomy.

DESIGN, SETTING, AND PARTICIPANTS

After peritumoral cystoscopic injection of indocyanine green (ICG) 21 patients underwent open RC with FTD due to BC between June 2019 and June 2021. Intraoperatively, the FIS-00 Hamamatsu Photonics® NIRF camera was used to identify and resect fluorescent template sentinel regions (FTRs) followed by extended pelvic lymphadenectomy (ePLND) as oncological back-up.

OUTCOME MEASUREMENT AND STATISTICAL ANALYSIS

Descriptive analysis of positive and negative results per template region.

RESULTS AND LIMITATIONS

FTRs were identified in all 21 cases. Median time (range) from ICG injection to fluorescence detection was 75 (55-125) minutes. On average (SD), 33.4 (9.6) lymph nodes were dissected per patient. Considering template regions as the basis of analysis, 67 (38.3%) of 175 resected regions were NIRF-positive, with 13 (7.4%) regions harboring lymph node metastases. We found no metastatic lymph nodes in NIRF-negative template regions. Outside the standard template, two NIRF-positive benign nodes were identified.

CONCLUSION

The concept of NIRF-guided FTD proved for this group all lymph node metastases to be found in NIRF-positive template regions. Pending validation in a larger collective, resection of approximately 40% of standard regions may be sufficient and may result in less morbidity.

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.

Evaluation of the Hybrid Tracer Indocyanine Green- 99m Tc-Nanocolloid for Sentinel Node Biopsy in Bladder Cancer-A Prospective Pilot Study

RATIONALE

In muscle-invasive bladder cancer (MIBC), lymph node invasion has proven to be an independent predictor of disease recurrence and cancer-specific survival. We evaluated the feasibility of targeting the sentinel node (SN) for biopsy in MIBC patients using the hybrid tracer indocyanine green (ICG)- 99m Tc-nanocolloid for simultaneous radioguidance and fluorescence guidance.

METHODS

Twenty histologically confirmed cN0M0 MIBC patients (mean age, 63.3 years; range, 30-82 years), scheduled for radical cystectomy with SN biopsy and extended pelvic lymph node dissection (ePLND), were prospectively included. Twelve patients were operated on following neoadjuvant chemotherapy. The patients received lymphoscintigraphy as well as SPECT/CT after 4 transurethral injections of ICG- 99m Tc-nanocolloid (mean, 208 MBq; range, 172-229 MBq) around the tumor/scar in the detrusor muscle of the bladder on the day before radical cystectomy. Sentinel node resection was performed under radioguidance and fluorescence guidance.

RESULTS

Nineteen patients could be analyzed. On preoperative imaging, SNs could be identified in 10 patients (53%; mean, 1.6 SN/patient), which revealed drainage pathways outside the ePLND in 20% of the patients. Interesting to note is that 2 patients (10%) with preoperative nonvisualization displayed fluorescent and radioactive SNs during surgery. Location of the primary tumor near the left lateral side of the bladder seemed to be a factor for nonvisualization. Nodal harvesting with ePLND varied among patients (mean, 23.3). Histopathology confirmed tumor-positive nodes in 4 (21%) of all patients. In the 2 patients where an SN could be identified, the ePLND specimens were tumor-negative. All patients with tumor-positive nodes had advanced disease (stage III).

CONCLUSION

Sentinel node biopsy in bladder cancer using the hybrid tracer ICG- 99m Tc-nanocolloid is feasible, and preoperative imaging is predictive for the ability to perform SN biopsy in 83% of the patients who displayed an SN. In patients with a successful preoperative SN mapping using lymphoscintigraphy and SPECT/CT, the intraoperative SN guidance and detection were effective, even outside the ePLND area. As such, this study underscores the critical role that preoperative imaging plays in challenging image-guided surgery applications.

Methods of Sentinel Lymph Node Detection and Management in Urinary Bladder Cancer—A Narrative Review

Introduction: Detection of lymph node status in bladder cancer significantly impacts clinical decisions regarding its management. There is a wide range of detection modalities for this task, including lymphoscintigraphy, computed tomography, magnetic resonance imaging, single-photon emission computed tomography, positron emission tomography, and fluoroscopy. We aimed to study the pre- and intraoperative detection modalities of sentinel lymph nodes in urinary bladder cancer. Method: This narrative review was performed by searching the PubMed and EMBASE libraries using the following search terms: (“Transitional cell carcinoma of the bladder” OR “urothelial cancer” OR “urinary bladder cancer” OR “bladder cancer”) AND ((“sentinel lymph node”) OR (“lymphatic mapping”) OR (“lymphoscintigraphy”) OR (“lymphangiography”) OR (“lymph node metastases”)). Studies analysing the effectiveness and outcomes of sentinel lymph node detection in bladder cancer were included, while non-English language, duplicates, and non-article studies were excluded. After analysing the libraries and a further manual search of bibliographies, 31 studies were included in this paper. We followed the RAMESES publication standard for narrative reviews to produce this paper. Results: Of the 31 studies included, 7 studies included multiple detection methods; 5 studies included lymphoscintigraphy; 5 studies included computed tomography and/or single-photon emission computed tomography; 5 studies included fluoroscopy; 4 studies included magnetic resonance imaging; and 5 studies included positron emission tomography. Discussion: Anatomical, radioactive, and functional detection modalities have been studied independently and in combination. The consensus is that preoperative detection with imaging helps guide surgical management and intraoperative detection methods help capture any lymph nodes that may have been missed. Each of these types of detection represent their own set of benefits and drawbacks, but there is currently limited evidence to support any change in overall practice to replace conventional staging.

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.