Sentinel node navigation surgery in esophageal cancer

History and evidence for state of the art of lymphadenectomy in esophageal cancer surgery

The current curative multimodal treatment of advanced esophageal cancers consists of neoadjuvant or perioperative chemo(radio)therapy followed by a radical surgical resection of the primary tumor and a 2- or 3-field lymphadenectomy. One of the most important predictors of long-term survival of esophageal cancer patients is lymph node involvement. The distribution pattern of lymph node metastases in esophageal cancer is unpredictable and depends on the primary tumor location, histology, T-stage and application of neoadjuvant or perioperative treatment. The optimal extent of the lymphadenectomy remains controversial; there is no global consensus on this topic yet. Some surgeons advocate an aggressive and extended lymph node dissection to remove occult metastatic disease, to optimize oncological outcomes. Others promote a more restricted lymphadenectomy, since the benefit of an extended lymphadenectomy, especially after neoadjuvant chemoradiotherapy, has not been clearly demonstrated, and morbidity may be reduced. In this review, we describe the development of lymphadenectomy, followed by a summary of current evidence for lymphadenectomy in esophageal cancer treatment.

Esophageal cancer: Treatment advances and need for screening

ABSTRACT

Esophageal cancer is a challenging malignancy that often is diagnosed in advanced stages, resulting in a poor prognosis. This article provides a comprehensive review of the two main types of esophageal cancer, esophageal squamous cell carcinoma and esophageal adenocarcinoma, and reviews epidemiology, risk factors, pathogenesis, diagnostic modalities, staging systems, and established and emerging treatments. Recent advancements in treatment for resectable and unresectable esophageal cancer also are explored. These include immunotherapy, targeted therapy, sentinel lymph node mapping, radiogenomics, palliative measures, and screening measures.

Use of Indocyanine Green Fluorescence Imaging in Thoracic and Esophageal Surgery

BACKGROUND

Fluorescence imaging using indocyanine green in thoracic and esophageal surgery is gaining popularity because of the potential to facilitate surgical planning, to stage disease, and to reduce postoperative complications. To optimize use of fluorescence imaging in thoracic and esophageal surgery, an expert panel sought to establish a set of recommendations at a consensus meeting.

METHODS

The panel included 12 experts in thoracic and upper gastrointestinal surgery from Asia-Pacific countries. Before meeting, 7 focus areas were defined: intersegmental plane identification for sublobar resections; pulmonary nodule localization; lung tumor detection; bullous lesion detection; lymphatic mapping of lung tumors; evaluation of gastric conduit perfusion; and lymphatic mapping in esophageal surgical procedures. A literature search of the PubMed database was conducted using keywords indocyanine green, fluorescence, thoracic, surgery, and esophagectomy. At the meeting, panelists addressed each focus area by discussing the most relevant evidence and their clinical experiences. Consensus statements were derived from the proceedings, followed by further discussions, revisions, finalization, and unanimous agreement. Each statement was assigned a level of evidence and a grade of recommendation.

RESULTS

A total of 9 consensus recommendations were established. Identification of the intersegmental plane for sublobar resections, localization of pulmonary nodules, lymphatic mapping in lung tumors, and assessment of gastric conduit perfusion were applications of fluorescence imaging that have the most robust current evidence.

CONCLUSIONS

Based on best available evidence and expert opinions, these consensus recommendations may facilitate thoracic and esophageal surgery using fluorescence imaging.

Feasibility and Safety of Tailored Lymphadenectomy Using Sentinel Node-Navigated Surgery in Patients with High-Risk T1 Esophageal Adenocarcinoma

BACKGROUND

Selective lymphadenectomy using sentinel node-navigated surgery (SNNS) might offer a less invasive alternative to esophagectomy in patients with high-risk T1 esophageal adenocarcinoma (EAC). The aim of this study was to evaluate the feasibility and safety of a new treatment strategy, consisting of radical endoscopic resection of the tumor followed by SNNS.

METHODS

In this multicenter pilot study, ten patients with a radically resected high-risk pT1cN0 EAC underwent SNNS. A hybrid tracer of technetium-99m nanocolloid and indocyanine green was injected endoscopically around the resection scar the day before surgery, followed by preoperative imaging. During surgery, sentinel nodes (SNs) were identified using a thoracolaparoscopic gammaprobe and fluorescence-based detection, and subsequently resected. Endpoints were surgical morbidity and number of detected and resected (tumor-positive) SNs.

RESULTS

Localization and dissection of SNs was feasible in all ten patients (median 3 SNs per patient, range 1-6). The concordance between preoperative imaging and intraoperative detection was high. In one patient (10%), dissection was considered incomplete after two SNs were not identified intraoperatively. Additional peritumoral SNs were resected in four patients (40%) after fluorescence-based detection. In two patients (20%), a (micro)metastasis was found in one of the resected SNs. One patient experienced neuropathic thoracic pain related to surgery, while none of the patients developed functional gastroesophageal disorders.

CONCLUSIONS

SNNS appears to be a feasible and safe instrument to tailor lymphadenectomy in patients with high-risk T1 EAC. Future research with long-term follow-up is warranted to determine whether this esophageal preserving strategy is justified for high-risk T1 EAC.

Prognostic relevance of tumor-resident memory T cells in metastatic lymph nodes of esophageal squamous cell carcinoma

Tumor-resident memory T (T_RM ) cells in primary tumors are reportedly associated with a favorable prognosis in several malignancies. However, the behaviors and functions of T_RM cells in regional lymph nodes (LNs) of esophageal cancer remain poorly understood. The aim of this study was to elucidate the effects of T_RM cells in regional LNs of esophageal cancer on clinicopathological findings and prognosis. Specimens of esophageal cancer and primary metastatic LNs (recurrent nerve LNs) were obtained from 84 patients who underwent radical esophagectomy between 2011 and 2017. We performed immunohistochemistry to enumerate and analyze T_RM cells, and used flow cytometry to investigate the function of T_RM cells. T_RM cells were observed in both metastatic LNs and primary tumors. T_RM cell-rich specimens exhibited reduced lymphatic invasion and LN metastasis and prolonged survival compared with T_RM cell-poor specimens. T_RM cells in metastatic LNs were more significantly associated with enhanced survival than T_RM cells in primary tumors. T_RM cells expressed high levels of granzyme B as a cytotoxicity marker. Our results suggested that high T_RM cell infiltration in metastatic LNs improves survival even though LN metastasis is commonly associated with poor prognosis. T_RM cells possibly contribute to antitumor immunity in regional LNs.

Feasibility of sentinel node navigated surgery in high-risk T1b esophageal adenocarcinoma patients using a hybrid tracer of technetium-99 m and indocyanine green

BACKGROUND

Minimally invasive esophagectomy with two-field lymphadenectomy is standard of care for T1b esophageal adenocarcinoma (EAC) with a high risk of lymph node metastasis. Sentinel node navigation surgery (SNNS) is a well-known concept to tailor the extent of lymphadenectomy. The aim of this study was to evaluate the feasibility and safety of SNNS with a hybrid tracer (technetium-99 m/indocyanine green/nanocolloid) for patients with high-risk T1b EAC.

METHODS

In this prospective, multicenter pilot study, 5 patients with high-risk T1b EAC were included. The tracer was injected endoscopically around the endoscopic resection scar the day before surgery, followed by preoperative imaging (lymphoscintigraphy/SPECT-CT). During surgery, first the SNs were localized and resected based on preoperative imaging and intraoperative gammaprobe- and fluorescence-based detection, followed by esophagectomy. Primary endpoints were the percentage of patients with detectable SNs, concordance between preoperative and intraoperative SN detection, and the additive value of indocyanine green.

RESULTS

SNs could be identified and resected in all patients (median 3 SNs per patient, range 2-7). There was a high concordance between preoperative and intraoperative SN detection. In 2 patients additional peritumoral SNs were identified with fluorescence-based detection. None of the resected lymph nodes showed signs of (micro)metastases and no nodal metastases were detected in the surgical resection specimen.

CONCLUSIONS

SNNS using technetium-99 m/indocyanine green/nanocolloid seems feasible and safe in patients with high-risk T1b EAC. Indocyanine green fluorescence seems to be of additive value for detection of peritumoral SNs. Whether this approach can optimize selection for esophagectomy needs to be studied in future research.

Prognostic Significance of the Number and Extent of Metastatic Lymph Nodes in Patients with Esophageal Cancer: Comparison of the Union for International Cancer Control 8th Edition and Japan Esophageal Society Japanese Classification of Esophageal Cancer 11th Edition Classifications for Esophageal Cancer

BACKGROUND

The tumor, node, metastasis staging system of the Union for International Cancer Control (UICC) has been used worldwide for esophageal cancer, and, in Japan, the Japan Esophageal Society Japanese Classification of Esophageal Cancer (JES) has also been used; however, there is a big difference between the two classifications with regard to node staging. We hypothesized that these two node staging systems may lead to different outcome predictions in terms of tumor location.

METHODS

This study enrolled 409 patients who underwent esophagectomy at Keio University Hospital, Tokyo, Japan, between January 2005 and December 2017. We included those who underwent R0 or R1 resection or esophagectomy with additional organ excision, and excluded those who underwent salvage surgery. Thereafter, we investigated how the number or spread of metastatic lymph nodes affected the prognosis.

RESULTS

For all 409 patients, the 5-year overall survival rate was 64.1% and the 5-year recurrence-free survival rate was 58.4%. The concordance indices were 0.756 for UICC 8th edition pathological node staging and 0.732 for JES 11th edition pathological node staging (p = 0.06). Based on tumor location, the difference in the concordance indices between these two classifications was greatest for lower thoracic esophageal tumors (p = 0.02).

CONCLUSIONS

For all patients, the UICC 8th edition node staging system tended to reflect survival more precisely than that of the JES 11th edition. For lower thoracic esophageal tumors in particular, the former node staging system could be more useful.

Intraoperative laparoscopic detection of sentinel lymph nodes with indocyanine green and superparamagnetic iron oxide in a swine gallbladder cancer model

Mapping of sentinel lymph nodes (SLNs) can enable less invasive surgery. However, mapping is challenging for cancers of difficult-to-access visceral organs, such as the gallbladder, because the standard method using radioisotopes (RIs) requires preoperative tracer injection. Indocyanine green (ICG) and superparamagnetic iron oxide (SPIO) have also been used as alternative tracers. In this study, we modified a previously reported magnetic probe for laparoscopic use and evaluated the feasibility of detecting SLNs of the gallbladder using a laparoscopic dual tracer method by injecting ICG and SPIO into five swine and one cancer-bearing swine. The laparoscopic probe identified SPIO nanoparticles in the nodes of 4/5 swine in situ, the magnetic field counts were 2.5-15.9 μT, and fluorescence was detected in SLNs in all five swine. ICG showed a visual lymph flow map, and SPIO more accurately identified each SLN with a measurable magnetic field quite similar to the RI. We then developed an advanced gallbladder cancer model with lymph node metastasis using recombination activating gene 2-knockout swine. We identified an SLN in the laparoscopic investigation, and the magnetic field count was 3.5 μT. The SLN was histologically determined to be one of the two metastatic lymph nodes. In conclusion, detecting the SLNs of gallbladder cancer in situ using a dual tracer laparoscopic technique with ICG and SPIO was feasible in a swine model.

Current status and challenges in sentinel node navigation surgery for early gastric cancer

As an optimal surgical procedure to accurately evaluate lymph node (LN) metastasis during surgery with minimal surgical resection, we have been developing sentinel node (SN) biopsy for early gastric cancer since the 1990s. Twelve institutions from the Japanese Society of Sentinel Node Navigation Surgery (SNNS), including Keio University Hospital, conducted a multicenter prospective trial to validate the SN concept using the dual-tracer method with blue dye and a radioisotope. According to the results, 397 patients were included in the final analysis, and the overall accuracy in detecting LN metastasis using SN biopsy was 99% (383 of 387). Based on the validation study, we are targeting cT1N0 with a primary tumor of ≤4 cm in diameter as an indication for SN biopsy for gastric cancer. We are currently running a multicenter nonrandomized phase III trial to assess the safety and efficacy of SN navigation surgery. The Korean group has reported the result of a multicenter randomized phase III trial. Since meticulous gastric cancer in the remnant stomach was rescued by subsequent gastrectomy, the disease-specific survival was comparable between the two techniques, implying that SN navigation surgery can be an alternative to standard gastrectomy. With the development of SN biopsy procedure and treatment modalities, the application of SN biopsy will be expanded to achieve an individualized minimally invasive surgery.

Indocyanine green fluorescence imaging via endoscopic nasal biliary drainage during laparoscopic deroofing of liver cysts

Laparoscopic deroofing of liver cysts is widely accepted as the treatment of symptomatic huge liver cysts. As bile leakage is a common complication of this procedure, indocyanine green (ICG) imaging has played an active role in detecting intrahepatic biliary tract. However, infusion ICG imaging needs time rag after injection due to moving from bloodstream to bile, and also, additional injection is needed when the fluorescent imaging is not clear. To cover this weakness of ICG imaging, we first applied ICG imaging via 5-Fr endoscopic nasal biliary drainage (ENBD) during laparoscopic deroofing of liver cysts. This technique promptly gives us ICG imaging after ICG injection from ENBD; in addition, direct ICG imaging sometimes reveals minor leakage from sealing line and staple lines; therefore, we believe that direct ICG imaging via ENBD helps us to prevent post-operative bile leakage.

Sentinel node mapping for post-endoscopic resection gastric cancer: multicenter retrospective cohort study in Japan

BACKGROUND

Standard gastrectomy with systematic lymphadenectomy as an additional surgery after endoscopic resection (ER) causes a deterioration in long-term quality of life. If the sentinel lymph node (SN) basin concept can be applied in post-ER gastric cancer, minimal surgery can be applied without reducing the curability. This retrospective multicenter cohort study aimed to verify the validity of the SN basin concept in post-ER gastric cancer.

PATIENTS AND METHODS

Individual data of 132 patients who underwent SN mapping after ER were collected from 8 university hospitals in Japan from 2001 to 2016. Tracers were injected endoscopically in the submucosal layer at four sites around the post-ER scar. We compared the SN basin distribution of post-ER gastric cancer with that of 275 patients with non-ER gastric cancer.

RESULTS

Two cases of SN were unidentified, both involving a single tracer (SN detection rate: 98.5%). Nine cases (6.8%) of lymph node metastasis were found, of which eight had a metastatic lymph node within the SNs and one had a non-SN metastasis within the SN basin. The diagnostic sensitivity of SN mapping for lymph node metastasis was 88.9% in post-ER group and 95.7% in non-ER group (P = 0.490); the accuracy was 99.2% and 99.6% (P = 0.539), respectively. Regarding the SN basin, no significant intergroup differences were found regardless of the primary tumor location.

CONCLUSIONS

Our findings clarified the feasibility of SN mapping based on the SN basin concept in patients with gastric cancer who previously underwent ER.

Past, present, and future of three-field lymphadenectomy for thoracic esophageal cancer

In spite of repeated appeal of the effectiveness of three-field lymphadenectomy (3FL) by Japanese esophageal surgeons, it has not been accepted worldwide as a standard therapeutic measure for thoracic esophageal cancer. In this review, a concise summary of the history of 3FL, its present position, and its future perspective is discussed. Although a lack of randomized controlled trial (RCT) is one of the largest criticisms of 3FL, it seems difficult to make 3FL world-standard even if a RCT with a positive result was made. The essence of 3FL has revealed the fact that bilateral cervical paraesophageal nodes and nodes in the bilateral supraclavicular fossae are regional nodes of thoracic esophageal cancer. To let the world admit this essence should be the real endpoint of "3FL issue" without RCT. In the era of new modalities, Japanese surgeons should be free from the idea that 3FL is indispensable though the essence of 3FL should remain.

Assessment of Nonradioactive Multispectral Optoacoustic Tomographic Imaging With Conventional Lymphoscintigraphic Imaging for Sentinel Lymph Node Biopsy in Melanoma

Importance

The metastatic status of sentinel lymph nodes (SLNs) is the most relevant prognostic factor in breast cancer, melanoma, and other tumors. The conventional standard to label SLNs is lymphoscintigraphy with technetium Tc 99m. A worldwide shortage and known disadvantages of Tc 99m have intensified efforts to establish alternative, nonradioactive imaging techniques.

Objective

To assess a new nonradioactive method using multispectral optoacoustic tomographic (MSOT) imaging in comparison with conventional lymphoscintigraphic imaging for SLN biopsy (SLNB) in melanoma.

Design, Setting, and Participants

Analysis of a cross-sectional study was conducted at the University Hospital-Essen, Skin Cancer Center, Essen, Germany. Between June 2, 2014, and February 22, 2019, 83 patients underwent SLNB with an additional preoperative indocyanine green (ICG) application. Sentinel lymph node basins were preoperatively identified by MSOT imaging, and ICG-labeled SLNs were intraoperatively detected using a near-infrared camera. The surgeons were blinded to the lymphoscintigraphic imaging results in the beginning of the SLNB. Use of a γ probe was restricted until the SLNB procedure was attempted by the nonradioactive method.

Main Outcomes and Measures

Concordance of SLN basins and SLNs identified by MSOT imaging plus near-infrared camera vs lymphoscintigraphic imaging plus single-photon emission computed tomographic or computed tomographic imaging was assessed.

Results

Of the 83 patients (mean [SD] age, 54.61 [17.53] years), 47 (56.6%) were men. In 83 surgical procedures, 165 SLNs were excised. The concordance rate of ICG-labeled and Tc 99m-marked detected SLN basins was 94.6% (n = 106 of 112). Intraoperatively, 159 SLNs were detected using a near-infrared camera and 165 were detected by a γ probe, resulting in a concordance rate of 96.4%. Multispectral optoacoustic tomographic imaging visualized SLNs in all anatomic regions with high penetration depth (5 cm).

Conclusions and Relevance

The findings of this study suggest that nonradioactive SLN detection via MSOT imaging allows identification of SLNs at a frequency equivalent to that of the current radiotracer conventional standard. Multispectral optoacoustic tomographic imaging appears to be a viable nonradioactive alternative to detect SLNs in malignant tumors.