Sentinel lymph node in oesophageal cancer-a systematic review and meta-analysis

[Evidence for the extent and oncological benefit of lymphadenectomy for esophageal cancer]

The prognosis for esophageal cancer is determined in particular by the depth of infiltration (T stage) and lymph node metastasis (N status). In patients with locally advanced tumors, surgical resection is the current standard. The extent of the lymphadenectomy depends on the localization of the tumor, analogous to the choice of surgical technique. For adequate tumor staging and achievement of pN0 status, seven lymph nodes without tumor metastases are necessary by definition but the current guidelines recommend 20 lymph nodes as a benchmark in an expert consensus. Despite the importance of the lymph node status for the prognosis of the patient and the already standardized use of targeted imaging of sentinel lymph nodes in other oncological disciplines, there is neither a validated method nor sufficient evidence for the benefit of lymph node mapping in esophageal cancer. The discussion about the prognostic advantage of lymphadenectomy is particularly interesting in T1 early stage cancer. Due to the technical advances of interventional endoscopy in recent years, organ preservation using endoscopic submucosal dissection (ESD) or endoscopic mucosal resection (EMR) has not only become possible but also safe to carry out and thus established as the standard with better functional results; however, if one or more risk factors are present, endoscopic ablation is no longer defined as curative and should be supplemented by further treatment, usually non-organ-preserving resection. The step from organ-preserving interventional treatment with a low complication rate to a surgical procedure with significant mortality and morbidity as well as functional limitations seems immense and requires optimization, especially in view of the technical developments of surgery in recent years. This can either aim to identify the risk of lymph node metastases more precisely or to minimize the morbidity/mortality and functional limitations of additive treatment procedures. Approaches to this are currently the subject of research and have already been safely applied in individual pilot projects.

Semaphorin 3F (SEMA3F) influences patient survival in esophageal adenocarcinoma

In esophageal adenocarcinoma, the presence of lymph node metastases predicts patients' survival even after curative resection. Currently, there is no highly accurate marker for detecting the presence of lymph node metastasis. The SEMA3F/NRP2 axis was initially characterized in axon guidance and recent evidence has revealed its significant involvement in lymphangiogenesis, angiogenesis, and carcinogenesis. Hence, the objective of this study was to elucidate the roles of SEMA3F and its receptor NRP2 in esophageal adenocarcinoma. We conducted an immunohistochemical evaluation of SEMA3F and NRP2 protein expression in 776 patients with esophageal adenocarcinoma who underwent Ivor-Lewis esophagectomy at the University Hospital of Cologne. Total and positive cancer cell counts were digitally analyzed using QuPath and verified by experienced pathologists to ensure accuracy. Positive expression was determined as a cell percentage exceeding the 50th percentile threshold. In our cohort, patients exhibiting SEMA3F positive expression experience significantly lower pT- and pN-stages. In contrast, positive NRP2 expression is associated with the presence of lymph node metastases. Survival analyses showed that the expression status of NRP2 had no impact on patient survival. However, SEMA3F positivity was associated with a favorable patient survival outcome (median OS: 38.9 vs. 26.5 months). Furthermore, SEMA3F could be confirmed as an independent factor for better patient survival in patients with early tumor stage (pT1N0-3: HR = 0.505, p = 0.014, pT1-4N0: HR = 0.664, p = 0.024, pT1N0: HR = 0.483, p = 0.040). In summary, SEMA3F emerges as an independent predictor for a favorable prognosis in patients with early-stage esophageal adenocarcinoma. Additionally, NRP2 expression is linked to a higher risk of lymph node metastases occurrence. We hypothesize that low SEMA3F expression could identify patients with early-stage tumors who might benefit from more aggressive treatment options or intensified follow-up. Furthermore, SEMA3F and its associated pathways should be explored as potential tumor-suppressing agents.

Evolution of the treatment of esophageal cancer: artificial intelligence and the role of sentinel lymph node assessment in esophageal cancer

Sentinel lymph node (SLN) biopsy has revolutionized the staging and prognosis of breast cancer and melanoma. Because of the complicated lymphatic network around the esophagus, the utility of SLN biopsy for esophageal cancer is less clear. The accuracy of SLN mapping in esophageal cancer depends on tumor site, disease stage, use of neoadjuvant therapy, and patient characteristics. SLN biopsy may improve staging and result in less morbidity in patients with early esophageal cancer, compared with radical lymphadenectomy and esophagectomy. A recent study that investigated hybrid tracers in sentinel node navigation surgery (SNNS) demonstrated promising results for the detection of peritumoral SLNs. However, evidence that firmly establishes the concept of the SLN for esophageal cancer is still lacking. Big data analytics and artificial intelligence have been associated with improvements in the detection and prognosis of esophageal cancer. This review considers the roles of the evolving technologies of SLN biopsy and artificial intelligence, which together have the potential to further improve prognoses and outcomes for patients with esophageal cancer. Additional investigation is necessary to establish standardized protocols and to determine the long-term effectiveness of these approaches in settings involving neoadjuvant therapy and advanced-stage disease.

Extensive lymphadenectomy may improve survival in node negative oesophageal cancer

Lymph node metastases are a major prognostic factor in survival of patients with oesophageal cancer. The number of lymph nodes removed during oesophagectomy has been previously proven to be associated with improved survival. The aim of this study was to examine the effect of lymph node harvest on survival specifically in pathologically node negative (pN0) patients with oesophageal cancer. Data were extracted from a prospectively populated single-surgeon database of oesophageal resections for cancer. All consecutive patients with pN0 were included. Patient-specific risk adjusted analysis of overall and disease-free survival was performed to identify the number of lymph nodes associated with improved survival. Inclusion criteria were met by 137 patients (49 squamous cell carcinoma and 88 adenocarcinoma). Adjusted for cancer stage, tumour (histological type, degree of differentiation, lympho-vascular invasion, neo-adjuvant therapy) and patient related factors (age, sex), increased lymph node number was associated with significant improvement in overall (P = 0.045) and disease free (P = 0.030) survival. Lymph node count ≥ 17 was associated with improved overall and disease-free survival. In this cohort of patients with pathologically node-negative oesophageal cancer, lymph node count of 17 or above was associated with significantly improved survival.

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.

Sentinel node navigation surgery in esophageal cancer

Over the last 20 years, the sentinel node (SN) concept has been widely applied to the surgical staging of both breast cancer and melanoma. However, the validity of this concept has been controversial for esophageal cancer, because SN mapping for esophageal cancer is not considered to be technically easy because of the complicated multidirectional lymphatic networks of the esophagus and mediastinum. Nevertheless, studies including meta-analyses indicated that SN mapping may be feasible in early esophageal cancer. Transthoracic esophagectomy with three-field lymphadenectomy was developed as a potential curative procedure for thoracic esophageal cancer. However, this highly invasive procedure might increase morbidity and reduce patients' quality of life (QOL) after esophagectomy. Although further validation based on multicenter trials using the standard protocol of SN mapping for esophageal cancer is required, SN navigation surgery would enable us to carry out personalized and limited lymph node dissection which might reduce morbidity and maintain patients' QOL.

Identification of the Lymphatic Drainage Pattern of Esophageal Cancer with Near-Infrared Fluorescent Imaging

OBJECTIVE

Nodal status is one of the most important long-term prognostic factors for esophageal cancer. The aim of this study was to evaluate the ability of near-infrared (NIR) light fluorescent imaging to identify the lymphatic drainage pattern of esophageal cancer.

METHODS

Patients with distal esophageal cancer or esophagogastric junction cancer scheduled for esophagectomy were enrolled in this study. Before surgery, an endoscopy was performed with submucosal injection of 2 cc of indocyanine green (ICG) around the tumor. Real-time NIR images from the surgical field were obtained for each patient to visualize the lymphatic ICG drainage.

RESULTS

A total of nine patients were included in this study. Ivor Lewis esophagectomy was performed in all cases. ICG drainage was visualized to first drain along the left gastric nodes in eight patients (88.9%) and toward the diaphragmatic nodes in one patient (11.1%). The median number of resected nodes was 32. Three patients (33.3%) presented nodal involvement. All of them had positive nodes in the first nodal station identified with ICG.

CONCLUSIONS

Evaluation of the lymphatic drainage pattern with real-time NIR light fluorescent technique is feasible. Distal and esophagogastric junction tumors showed to drain first in the left gastric nodes in most of the cases.

Lymphadenectomy and health-related quality of life after oesophageal cancer surgery: a nationwide, population-based cohort study

OBJECTIVE

The purpose of this study was to clarify whether more extensive surgical lymph node resection during oesophageal cancer surgery influences patients' health-related quality of life (HRQOL).

SETTING

This was a nationwide Swedish population-based study.

PARTICIPANTS

A total of 616 patients who underwent curatively intended oesophageal cancer surgery in 2001-2005 were followed up at 6 months and 5 years after surgery.

OUTCOME MEASURES

HRQOL was assessed with the validated European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core-30 (EORTC QLQ-C30) and the oesophageal cancer-specific module (EORTC QLQ-OES18). The number of removed lymph nodes in relation to HRQOL was analysed using multivariable linear regression, providing mean score differences in HRQOL scores with 95% CIs. The results were adjusted for age, comorbidity, body mass index, tumour stage, tumour histology, postoperative complications and surgeon volume.

RESULTS

The study included 382 and 136 patients who completed the EORTC questionnaires at 6 months and 5 years following surgery, respectively. In general, HRQOL remained stable over time, with only improvements in role function and appetite loss. A larger number of removed lymph nodes did not decrease the HRQOL measure at 6 months or 5 years after surgery.

CONCLUSIONS

More extensive lymphadenectomy during oesophageal cancer surgery might not decrease patients' short-term or long-term HRQOL, but larger studies are needed to establish this potential lack of association.

Retrograde Lymphatic Spread of Esophageal Cancer: A Case Report

The concept of the retrograde lymphatic spread of cancer cells appears to account for a subset of the essential mechanisms of cancer metastasis in various organs. However, no adequate data currently exist to illustrate the pathology of the retrograde lymphatic metastasis of cancer cells in human bodies. To shed light on this phenomenon, we report a case of a 63-year-old Japanese man who underwent an esophagectomy and lymph node dissection for early-stage esophageal cancer.The patient's clinical information was evaluated by board-certified surgeons and internists. Surgically excised materials were histopathologically evaluated by attending pathologists.Postoperative pathological examination revealed that the patient's tumor was a well-differentiated squamous cell carcinoma with negative surgical margins (T1N0M0, stage I). Apart from the primary lesion, a single lymphatic vessel invasion was found between the lamina propria and lamina muscularis of the esophagus where intralymphatic cancer cells had spread against the direction of backflow prevention valves and skipped beyond these valves without destroying them.The present case demonstrated that the retrograde lymphatic spread of cancer cells can occur in valve-equipped lymphatic vessels. Our study may not only provide a scientific basis for the concept of retrograde lymphatic metastasis but also explain a portion of the complexities associated with the lymphogenous metastasis of esophageal cancer.