[Sentinel lymph node mapping in gastric and esophageal carcinomas]

Accuracy of sentinel node biopsy in esophageal carcinoma: a systematic review and meta-analysis of the pertinent literature

The use of sentinel node surgery for esophageal carcinoma is still under investigation. We evaluated the data available in the literature on this topic, and herein present the results in a systematic review format. PUBMED, SCOPUS, the ISI web of knowledge and the information from the annual meetings of the Japan Esophageal Society were searched using the search terms: "(esophagus OR esophageal) AND sentinel". The outcomes of interest were the detection rate and sensitivity. Overall, 18 studies were included. The pooled detection rate was 89.2% [82.6-93.5]. Patients with T1 and two tumors had a 17% higher detection rate compared to those with T3 and four tumors. The pooled sensitivity was 84% [78-88%]. The sensitivity was higher for adenocarcinoma compared to squamous cell carcinoma (SCC) (91 vs. 81%). In the SCC patients, there was a trend toward decreased sensitivity associated with an increasing tumor depth (T1:88%, T2:76%, T3:50%). Our analysis indicated that sentinel node biopsy is useful in adenocarcinoma patients. For SCC patients, including only cN0 patients (preferably T1 and 2) would increase the detection rate and sensitivity. Due to the limited number of high-quality studies, drawing any more definite conclusions is impossible. Large cohort studies with a standardized and consistent design will be needed in the future.

Gastric cancer: surgery in 2011

BACKGROUND

Treatment of gastric cancer is more and more becoming an individualized decision. The choice of the optimal approach is based on prognostic factors, on the anatomic site of the tumor, and on expectations about the response to neoadjuvant treatment. Early gastric cancer that is limited to the mucosal layer is the domain of endoscopic resections. As soon as the submucosal layer is invaded, surgical strategies with adequate lymphadenectomy become necessary.

DISCUSSION

In many East Asian Centers and some other centers in the world, these tumors are resected by a laparoscopic approach. With a high experience, this can be done with excellent quality and outcome. In locally advanced gastric cancer, multimodal treatment can improve survival in comparison to surgery alone. However, the strategies differ significantly around the world. While adjuvant chemoradiotherapy is standard in the USA, in Europe, perioperative chemotherapy is the first choice, and in Japan, adjuvant chemotherapy is recommended. In Europe, three randomized phase III studies on the value of preoperative chemotherapy have been performed. Two of them have shown that perioperative chemotherapy does significantly improve the survival of patients with adenocarcinoma of the stomach and of the esophagogastric junction. The one including only preoperative chemotherapy failed to show a survival benefit for the combined treatment arm but showed excellent outcomes in both the surgery alone and the preoperative chemotherapy arms. Based on these studies, patients with stage II or stage III disease are now treated with perioperative chemotherapy. Additionally, it is generally accepted for more than 10 years now that responding patients have a significantly improved prognosis compared to nonresponding patients. The percentage of responding patients varies depending on the applied regimen between 20% and 45%. Therefore, early response evaluation or response prediction is an utmost important field of research. Proximal tumors are treated with a transhiatal extended gastrectomy, tumors in the middle third with a total gastrectomy, and distal tumors with a subtotal gastrectomy, if possible. Modified D2 lymphadenectomy avoiding splenectomy is now accepted as the standard procedure, providing improved prognosis for certain subgroups of patients. Individualized resection and lymphadenectomy techniques for early tumor stages and response-based neoadjuvant concepts for locally advanced tumors are the challenge for the future.

Current status of sentinel lymph node biopsy in adenocarcinoma of the distal esophagus, gastric cardia, and proximal stomach

The resection of the adenocarcinoma of the esophagogastric junction should be considered to the extent of the lymphatic drainage. This, on the other hand, depends on the possible lymphatic metastasizing. As an adenocarcinoma of the esophagogastric junction is located along the borderline between two visceral cavities (mediastinal/abdominal), it can, in principle, metastasize in both cavities. There is not, however, an imaging (CT, MRI, PET) that can adequately assure the detection of a beginning lymph node metastasis in particular. The sentinel lymph node biopsy could provide the beginning of a solution in this case. The initial results, with all of the necessary accompanying technical work, have been encouraging. The paper presented here provides an introduction to the challenge of the SLNB and the background of a specialized surgical therapy of the AEG. If a lymph nodal metastasis can be definitely confirmed or ruled out, many patients could be spared an unnecessary lymphadenectomy. This is especially important at the AEG because minimizing the evasiveness of the surgery with adequate radical oncological resection (e.g., without thoracotomy) would mean a substantial reduction of postoperative mortality.

Sentinel lymph node in esophageal cancer before neoadjuvant therapy

The technique of sentinel lymph node identification and biopsy has become a new popular technique for surgeon to improve staging of malignant diseases. It may also reduce the risk of complication related to standard lymphadenectomy. The method is still in experimental phase in case of esophageal cancer. A possible complication for employment of the method in this tumor is neoadjuvant therapy. The authors developed the technique for identifying and obtaining the sentinel lymph node in esophageal cancer using minimally invasive surgical technique before neoadjuvant therapy. The sentinel lymph node is detected using 99mTc-labelled nanocolloid. The authors report and discuss possible difficulties of the method in the case of a patient with detected sentinel lymph node in this way.

CONCLUSION

It is possible to identify and obtain a sentinel lymph node before neoadjuvant therapy in esophageal cancer. On the other hand, the clinical significance and applicability of the method of sentinel lymph node still remains controversial in this kind of a tumor.

Multimodal treatment of gastrointestinal tract tumors: consequences for surgery

Formerly an exclusive business of surgery, gastrointestinal (GI) tumors are nowadays increasingly approached with multimodal strategies. Neoadjuvant concepts have had a particularly far-reaching impact on surgery and have contributed to improved survival. Modern pre-treatment staging and risk assessment provide the basis for decision on one of three general treatment concepts (1) Early cancers, confined to the mucosal/submucosal layers, are approached with primary surgery, without prior antineoplastic therapy. (2) Systemically metastasized tumors receive merely palliative treatment. (3) Locally advanced cancers are increasingly approached with neoadjuvant strategies. The benefit from these preoperative protocols is proven for diverse entities, but is evidently confined to a specific subgroup patients, i.e., the responders to neoadjuvant treatment. These are the ones benefiting most from subsequent surgical resection, which is required to ensure complete removal of the residual tumor tissue, as complete tumor regression occurs very rarely and cannot be proven without a specimen. The fact that responders will benefit and non-responders will not benefit or will even deteriorate during the neoadjuvant treatment makes early response prediction most demanding. An amazing new approach is the use of position emission tomography with fluro-desoxyglucose (FDG-PET) to assess the "metabolic response," which is possible as early as 14 days after initiation of the neoadjuvant protocol. This strategy offers the chance for modulating the surgical approach in accord i.e., with such metrobolic response termination of the protocol and proceeding to resection in the case of nonresponse. The future of GI cancer surgery is multimodal therapy in a response-based fashion and requires reponse-based trials for further evaluation.