Sentinel node navigation surgery in cervical cancer: a systematic review and metaanalysis

Sentinel node navigation surgery (SNNS) is used in clinical practice for the treatment of cervical cancer. This study aimed to elucidate the appropriate sentinel lymph node (SLN) mapping method and assess the safety and benefits of SNNS. We searched the PubMed, Ichushi, and Cochrane Library databases for randomized controlled trials (RCT) and studies on SLN in cervical cancer from January 2012 to December 2020. Two authors independently assessed study quality and extracted data. We quantitatively analyzed the detection rate, sensitivity/specificity, and complications and reviewed information, including the survival data of SLN biopsy (SLNB) without pelvic lymphadenectomy (PLND). The detection rate of SLN mapping in the unilateral pelvis was median 95.7% and 100% and in the bilateral pelvis was median 80.4% and 90% for technetium-99 m (Tc) with/without blue dye (Tc w/wo BD) and indocyanine green (ICG) alone, respectively. The sensitivity and specificity of each tracer were high; the area under the curve of each tracer was 0.988 (Tc w/wo BD), 0.931 (BD w/wo Tc), 0.966 (ICG), and 0.977 (carbon nanoparticle). Morbidities including lymphedema, neurological symptoms and blood loss were associated with PLND. One RCT and five studies all showed SNNS without systematic PLND does not impair recurrence or survival in early-stage cervical cancer with a tumor size ≤ 2-4 cm. Both Tc w/wo BD and ICG are appropriate SLN tracers. SNNS can reduce the morbidities associated with PLND without affecting disease progression in early-stage cervical cancer.

What's New with Endoscopic Treatments for Early Gastric Cancer in the "Post-ESD Era"?

BACKGROUND

Endoscopic treatments for gastric cancers have still been progressing even after the great success of endoscopic submucosal dissection (ESD).

SUMMARY

In further advancements of ESD, safe and less-invasive procedures are challenged by managing postoperative bleeding, one of the major adverse events in ESD. Covering the mucosal defect after removal of lesions appears reasonable and effective for preventing delayed bleeding from the post-ESD ulcers. Shielding with biodegradable sheets is attempted on clinical trials, which show equivocal results. Although suturing of the mucosal rims is technically challenging, pilot studies demonstrate favorable outcomes for avoiding post-ESD bleeding even in cases at high risk. In cases after noncurative resection of ESD, the selection of patients who truly require additional gastrectomy with lymph node dissection is important to provide necessary surgery. Risk stratification of lymph node metastases and surgery has been developed, which offers tailor-made management to each patient considering the risks and benefits. In surgery, function-preserving gastrectomy to minimize the resection area in both lymphadenectomy and the primary site is clinically introduced. The sentinel node navigation surgery is promising to realize the minimally invasive gastrectomy, and it should strongly fit ESD as well as laparoscopic endoscopic cooperative surgery or endoscopic full-thickness resection, although nonexposure approaches are desirable. Key Message: Development for less-invasive managements on gastric cancer will be continued in step with the advancement of endoscopic treatments.

Recent updates and current issues of sentinel node navigation surgery for early gastric cancer

With the increase in the incidence of early gastric cancer (EGC), several endoscopic and laparoscopic approaches, such as endoscopic submucosal dissection and function-preserving gastrectomy, have been accepted as standard treatments. Sentinel node navigation surgery (SNNS) is an ideal surgical option for preservation of most parts of the stomach and consequent maintenance of normal gastric function to improve quality of life in patients with EGC. Although many previous studies and clinical trials have demonstrated the safety and feasibility of the sentinel node concept in gastric cancer, the clinical application of SNNS is debatable. Several issues regarding technical standardization and oncological safety need to be resolved. Recently several studies to resolve these problems are being actively performed, and SNNS might be an important surgical option in the treatment of gastric cancer in the future.

[Combined laparoscopy-endoscopy local resection for early gastric cancer]

The surgical treatment of early gastric cancer (EGC) is undergoing the development of minimally invasive, precise and individualized treatment. The concept is changing from simple emphasis on radical treatment to giving consideration to both radical treatment and functional preservation. Combined laparoscopy-endoscopy local resection can achieve accurate resection of the lesions of EGC and solve the problem of lymph node dissection which cannot be performed in endoscopic mucosal dissection (ESD). At present, there are several methods of combined laparoscopy-endoscopy local resection for EGC, such as laparoscopy-assisted endoscopic full-thickness resection (EFTR), endoscopy-assisted wedge resection (EAWR), combined laparoscopic and endoscopic approach for neoplasia with a non-exposure technique (CLEAN-NET), and non-exposed endoscopic wall-inversion surgery (NEWS). These methods of local resection have the advantages of minimal invasion, shorter operation time, and less blood loss compared to conventional gastrectomy. Concerning the issue of lymph node dissection in combined laparoscopy-endoscopy surgery, sentinel node navigation can be the solution, although cumbersome intraoperative lymph node tracing, operative failure and false negative still exist. As a developing treatment for EGC, combined laparoscopy-endoscopy local resection will have a good application prospect in the future.

Evaluation of postoperative quality of life by PGSAS-45 following local gastrectomy based on the sentinel lymph node concept in early gastric cancer

BACKGROUND

The usefulness of sentinel node navigation surgery (SNNS) for early gastric cancer has been demonstrated in a multicenter prospective study. However, quality of life (QOL) after local resection remains unclear. This present study investigated QOL after local resection and distal gastrectomy.

METHODS

We examined 69 patients who underwent laparoscopic distal gastrectomy (LADG) (n = 44) and laparoscopic local resection (LLR) (n = 25) in our hospital between September 2011 and May 2018. We conducted a combination of laparoscopic and endoscopic approaches to neoplasia with non-exposure technique (CLEAN-NET) with SNNS as LLR. All patients had pStage I or II and none had received adjuvant chemotherapy. We evaluated QOL using the postgastrectomy syndrome assessment scale questionnaire (PGSAS-45) 1, 6, and 12 months after surgery.

RESULTS

In PGSAS-45, no significant differences were observed between LLR and LADG at 1 and 6 months after surgery. At 12 months, the LLR group scored better for some of the subscales (SS). In the endoscopic evaluation, the LLR group showed significant improvements in residual gastritis at 6 months (P = 0.006) and esophageal reflux and residual gastritis at 12 months (P = 0.021 and P = 0.017). A significant difference was observed in the prognostic nutritional index, which was assessed using serum samples, between the two groups at 6 months (P = 0.028). The body weight ratio was better in the LLR group than in the LADG group at 6 and 12 months (P = 0.041 and P = 0.007, respectively).

CONCLUSIONS

CLEAN-NET with SNNS preserved a better QOL and nutrition status than LADG in patients with early gastric cancer.

Burgeoning study of sentinel-node analysis on management of early gastric cancer after endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) represents an organ-preserving alternative to surgical resection of early gastric cancer. However, even with ESD yielding en-bloc resection specimens, there are concerns regarding tumor spread such as with larger lesions, ulcerated lesions, undifferentiated pathology and submucosal invasion. Sentinel node navigational surgery (SNNS) when combined with ESD offers a minimally invasive alternative to the traditional extended gastrectomy and lymphadenectomy if lack of lymph node spread can be confirmed. This would have a clear advantage in terms of potential complications and quality of life. However, SNNS, though useful in other malignancies such as breast cancer and melanoma, may not have a sufficient sensitivity for malignancy and negative predictive value in EGC to justify this as standard practice after ESD. The results of SNNS may improve with greater standardization and more involved dissection, technological innovations and more experience and validation such that the paradigm for post-ESD resection of EGC may change and include SNNS.

Potential for local resection with sentinel node basin dissection for early gastric cancer based on the distribution of primary sites

BACKGROUND

Based on the sentinel node (SN) concept, function-preserving surgery with SN basin dissection (SNBD) can be performed for SN-negative early gastric cancers. Particularly, a resection area can be minimized when the SN basin and primary site are closely localized. The aim of this study was to compare probabilities of being candidates for local resection with SNBD based on tumor location among patients with early gastric cancer.

METHODS

We retrospectively analyzed 358 patients who underwent surgery with SN mapping for gastric cancer in our institution from November 1999 to April 2014. The proportion of patients who had a localized single basin and the distributions of the SN basins and primary sites were investigated. Patients with single basin drainage excluding remote sentinel node basin were considered as candidates for local resection with SNBD.

RESULTS

Of the 358 patients, 191 (53%) patients were considered eligible for local resection with SNBD. Patients with tumors located in the upper third of the stomach were more likely candidates for local resection than those with tumors in other locations (upper third, 68%; middle third, 50%; and lower third, 51%), whereas patients with tumors located in the anterior wall were less likely candidates than those with tumors other locations (anterior wall, 31%; posterior wall, 58%; greater curvature, 55%; and lesser curvature, 57%).

CONCLUSION

We found that > 50% of the patients indicated for SN navigation surgery, particularly those with tumors in the upper third of the stomach, potentially could undergo partial resection with SNBD.

Quantitative assessment of fluorescence intensity of ICG in sentinel nodes in early gastric cancer

BACKGROUND

The sentinel node (SN) detection by dual tracer method using indocyanine green (ICG) and a radioisotope (RI) has been recommended for early gastric cancer. However, institutions are limited due to radioactivity in the RI method. The greatest advantage of the RI method is that it objectively assesses RI uptake as a numerical value. The aim of the present study was to verify the usefulness of ICG fluorescence intensity in SN.

METHODS

Seventeen patients with early gastric cancer were enrolled in this study. RI uptake by each lymph node was measured using Navigator GPS and fluorescence nodes were identified using the hyper eye medical system (HEMS). Fluorescence intensity in fluorescence nodes was evaluated using ICG intensity imaging software (Mizuho, Japan) of the HEMS.

RESULTS

The total number of dissected lymph nodes was 227, with an average of 13.3 per patient. The numbers of HN, FN-S, and FN-B were 64, 77, and 34. RI uptake was significantly greater by FN-S than by non-FN-S (P = 0.0016). The median fluorescence intensity value was higher in HN than in non-HN (P < 0.001). A correlation was observed between RI uptake and fluorescence intensity. Dissecting FNs with fluorescence intensity levels of 1-6 resulted in 92.1% dissection of HNs.

CONCLUSION

It is possible that the evaluation of fluorescence intensity is useful for selected SNs instead of RI tracer. If fluorescence intensity is measurable in surgery, an infrared fluorescence method using ICG may be useful and safe for the detection of SN in early gastric cancer.

Sentinel node navigation surgery using near-infrared indocyanine green fluorescence in early gastric cancer

BACKGROUND

The aim of this study was to evaluate the feasibility of indocyanine green (ICG) fluorescent method for sentinel lymph node detection in early gastric cancer.

METHODS

Between December 2012 and December 2014, 28 cases of pilot examination were performed at Seoul National University Bundang Hospital. Advanced version of multispectral fluorescence organoscope was used to identify sentinel node by quantitative estimation of ICG fluorescent signal intensity. Sensitivity, specificity, false positive value were analyzed and compared with dual tracer method.

RESULTS

A total of 443 lymph nodes in 28 cases were examined and 184 sentinel nodes (41.5%) were identified by dual tracer method. The sensitivity using near-infrared ICG method was 98.9%. The specificity was 76.0% and false positive rate was 25.4% compared with dual tracer method. The adequate threshold for sentinel node detection was considered as 10% of maximum signal intensity.

CONCLUSION

New near-infrared ICG fluorescent method could be a promising protocol for sentinel node navigation surgery in early gastric cancer.

Prognostic outcome and complications of sentinel lymph node navigation surgery for early-stage cervical cancer

BACKGROUND

To evaluate the prognostic outcome and surgical complications in patients with early-stage cervical cancer who underwent sentinel node navigation surgery (SNNS) for hysterectomy or trachelectomy.

METHODS

A total of 139 patients who underwent SNNS using ^99mTc phytate between 2009 and 2015 were evaluated. No further lymph node dissection was performed when intraoperative analysis of the sentinel lymph nodes (SLNs) was negative for metastasis. We compared the surgical complications between the SNNS group and 67 matched patients who underwent pelvic lymph node dissection (PLND) after SLN mapping between 2003 and 2008. We also examined the clinical outcomes in the SNNS group.

RESULTS

The mean number of detected SLNs was 2.5 per patient. Fourteen of the 139 patients in the SNNS group underwent PLND based on the intraoperative SLN results. The amount of blood loss, the operative time, and the number of perioperative complications were significantly less in the SNNS group than in the matched PLND group. There was no recurrence during a follow-up period ranging from 2 to 88 months (median 40 months) in the SNNS group.

CONCLUSIONS

Using SNNS for early-stage cervical cancer is safe and effective and does not increase the recurrence rate. A future multicenter trial is warranted.

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

Although a number of feasibility studies for sentinel node (SN) concepts in gastric cancer have been conducted since 2000, there remains a debate regarding detailed detection techniques and oncological safety. Two important multicenter phase II clinical trials were performed in Japan that used different methods and reached different conclusions; one confirmed acceptable results with a false-negative rate of 7%, and the other showed an unacceptably high false-negative rate of 46.4%. The Sentinel Node Oriented Tailored Approach (SENORITA) trial is a multicenter randomized controlled phase III trial being performed in Korea. Patient enrollment is now complete and the long-term results are currently awaited. Recently, an image-guided SN mapping technique using infrared ray/fluorescence was introduced. This method might be a promising technology because it allows the clear visualization of SNs. With regard to the primary tumor, the non-exposed endoscopic wall-inversion surgery technique and non-exposure endolaparoscopic full-thickness resection with simple suturing technique have been reported. These methods prevent abdominal infection and tumor seeding and can be good alternatives to conventional laparoscopic gastric wedge resection. For indications, SN navigation surgery can be extended to patients who underwent non-curative endoscopic resection. Although a few studies have been performed on these patients, sentinel concepts may be beneficial to patients as they omit the need for additional gastrectomy. SN navigation surgery can lead to actual organ-preserving surgery and plays a key role in improving the quality of life of patients with early gastric cancer in the future.

Laparoscopic sentinel node navigation surgery for early gastric cancer: a prospective multicenter trial

BACKGROUND

Prospective multicenter trials have shown the feasibility of sentinel node (SN) navigation surgery using a dual tracer of dye and radioisotope for early gastric cancer. However, comparable trials using the indocyanine green (ICG) and the infrared ray laparoscopic system (IRLS) have not been reported. On the basis of our cohort studies, we assumed that the ICG imaging with the IRLS is as effective as the dual tracer in detecting SNs. Therefore, we conducted a prospective multicenter trial to assess the effectiveness and generalizability of the infrared ICG technique in patients with early gastric cancer.

PATIENTS AND METHODS

Patients with previously untreated cT1 gastric adenocarcinomas less than 4 cm in gross diameter were eligible for inclusion in this study. SN mapping was performed by using ICG combined with IRLS technique. Following biopsy of the identified SNs, D2 or modified D2 laparoscopic gastrectomy was performed according to the current Japanese Gastric Cancer Association guidelines.

RESULTS

Among the 47 patients who gave written informed consent, 44 were eligible from the surgical findings, for whom SN biopsy was performed. The detection rate of the lymphatic basin by the ICG with IRLS was 100% (44/44). The accuracy was also 100% (7/7) for detecting metastatic lymph node, which was verified on the permanent pathologic examination. Following the median follow-up of 114 months (range, 60 to 120 months), no recurrence (0/40) was observed. Although the number of patients was unequally distributed among the hospitals participating in the trial, the detection rates of SNs in low-volume hospitals were comparable to those in high-volume hospitals. Consequently, there was no learning curve in this trial.

CONCLUSION

The infrared ICG imaging accurately detected the lymphatic basin and SNs with occult metastasis in SN-navigated gastrectomy for gastric cancer. This method was feasible even for low-volume surgeons and hospitals.

Prediction of lymph node metastasis and sentinel node navigation surgery for patients with early-stage gastric cancer

Accurate prediction of lymph node (LN) status is crucially important for appropriate treatment planning in patients with early gastric cancer (EGC). However, consensus on patient and tumor characteristics associated with LN metastasis are yet to be reached. Through systematic search, we identified several independent variables associated with LN metastasis in EGC, which should be included in future research to assess which of these variables remain as significant predictors of LN metastasis. On the other hand, even if we use these promising parameters, we should realize the limitation and the difficulty of predicting LN metastasis accurately. The sentinel LN (SLN) is defined as first possible site to receive cancer cells along the route of lymphatic drainage from the primary tumor. The absence of metastasis in SLN is believed to correlate with the absence of metastasis in downstream LNs. In this review, we have attempted to focus on several independent parameters which have close relationship between tumor and LN metastasis in EGC. In addition, we evaluated the history of sentinel node navigation surgery and the usefulness for EGC.

Endoscopic Submucosal Dissection (ESD) and Related Techniques as Precursors of "New Notes" Resection Methods for Gastric Neoplasms

Endoscopic full-thickness resection for subepithelial tumors is one of the more attractive proposed methods for less-invasive transluminal surgery but remains challenging in terms of safety and feasibility. Currently, laparoscopic endoscopic cooperative surgery is thought to be a more clinically acceptable approach. In targeting cancers, however, more advanced nonexposure techniques are required to avoid the risk of iatrogenic tumor seeding. By combining these techniques with possible regional lymphadenectomy using sentinel node navigation surgery, an ideal minimally invasive, function-preserving gastric resection can be achieved even in possible node-positive cancers. Further development for this type of advanced endoscopic surgery is expected.

Sentinel node navigation surgery with indocyanine green fluorescence-guided method for metachronous early gastric carcinoma arising from reconstructed gastric tube after esophagectomy

A 67-year-old man who had undergone a thoracoscopic esophagectomy and posterior mediastinal gastric tube reconstruction for thoracic esophageal cancer 9 years previously was endoscopically diagnosed as having gastric carcinoma arising from the reconstructed gastric tube. No evidence of metastasis was seen in imaging examinations, and the depth of tumor invasion was suspected to be the submucosal layer. Based on these results, we decided that surgery, rather than endoscopic resection, was indicated. The tumor was located in the upper abdomen. Therefore, we performed a partial resection of the gastric tube. Sentinel nodes (SN) were identified using the Hyper Eye Medical System II. Metastasis was not observed in any of the selected SN. While the treatment strategy for gastric tube cancer after an esophagectomy remains controversial, minimally invasive surgery with sentinel node navigation surgery appears to be clinically useful. However, the method of SN dissection should be investigated with due consideration given to arterial preservation.

Cutting edge of endoscopic full-thickness resection for gastric tumor

Recently, several studies have reported local full-thickness resection techniques using flexible endoscopy for gastric tumors, such as gastrointestinal stromal tumors, gastric carcinoid tumors, and early gastric cancer (EGC). These techniques have the advantage of allowing precise resection lines to be determined using intraluminal endoscopy. Thus, it is possible to minimize the resection area and subsequent deformity. Some of these methods include: (1) classical laparoscopic and endoscopic cooperative surgery (LECS); (2) inverted LECS; (3) combination of laparoscopic and endoscopic approaches to neoplasia with non-exposure technique; and (4) non-exposed endoscopic wall-inversion surgery. Furthermore, a recent prospective multicenter trial of the sentinel node navigation surgery (SNNS) for EGC has shown acceptable results in terms of sentinel node detection rate and the accuracy of nodal metastasis. Endoscopic full-thickness resection with SNNS is expected to become a treatment option that bridges the gap between endoscopic submucosal dissection and standard surgery for EGC. In the future, the indications for these procedures for gastric tumors could be expanded.

Sentinel lymph node navigation surgery for early stage gastric cancer

We attempted to evaluate the history of sentinel node navigation surgery (SNNS), technical aspects, tracers, and clinical applications of SNNS using Infrared Ray Electronic Endoscopes (IREE) combined with Indocyanine Green (ICG). The sentinel lymph node (SLN) is defined as a first lymph node (LN) which receives cancer cells from a primary tumor. Reports on clinical application of SNNS for gastric cancers started to appear since early 2000s. Two prospective multicenter trials of SNNS for gastric cancer have also been accomplished in Japan. Kitagawa et al reported that the endoscopic dual (dye and radioisotope) tracer method for SN biopsy was confirmed acceptable and effective when applied to the early-stage gastric cancer (EGC). We have previously reported the usefulness of SNNS in gastrointestinal cancer using ICG as a tracer, combined with IREE (Olympus Optical, Tokyo, Japan) to detect SLN. LN metastasis rate of EGC is low. Hence, clinical application of SNNS for EGC might lead us to avoid unnecessary LN dissection, which could preserve the patient's quality of life after operation. The most ideal method of SNNS should allow secure and accurate detection of SLN, and real time observation of lymphatic flow during operation.

Sentinel node navigation surgery for gastric cancer: Overview and perspective

The sentinel node (SN) technique has been established for the treatment of some types of solid cancers to avoid unnecessary lymphadenectomy. If node disease were diagnosed before surgery, minimal surgery with omission of lymph node dissection would be an option for patients with early gastric cancer. Although SN biopsy has been well ascertained in the treatment of breast cancer and melanoma, SN navigation surgery (SNNS) in gastric cancer has not been yet universal due to the complicated lymphatic flow from the stomach. Satisfactory establishment of SNNS will result in the possible indication of minimally invasive surgery of gastric cancer. However, the results reported in the literature on SN biopsy in gastric cancer are widely divergent and many issues are still to be resolved, such as the collection method of SN, detection of micrometastasis in SN, and clinical benefit. The difference in the procedural technique and learning phase of surgeons is also varied the accuracy of SN mapping. In this review, we outline the current status of application for SNNS in gastric cancer.

Sentinel lymph node navigation surgery for early stage gastric cancer

We attempted to evaluate the history of sentinel node navigation surgery (SNNS), technical aspects, tracers, and clinical applications of SNNS using Infrared Ray Electronic Endoscopes (IREE) combined with Indocyanine Green (ICG). The sentinel lymph node (SLN) is defined as a first lymph node (LN) which receives cancer cells from a primary tumor. Reports on clinical application of SNNS for gastric cancers started to appear since early 2000s. Two prospective multicenter trials of SNNS for gastric cancer have also been accomplished in Japan. Kitagawa et al reported that the endoscopic dual (dye and radioisotope) tracer method for SN biopsy was confirmed acceptable and effective when applied to the early-stage gastric cancer (EGC). We have previously reported the usefulness of SNNS in gastrointestinal cancer using ICG as a tracer, combined with IREE (Olympus Optical, Tokyo, Japan) to detect SLN. LN metastasis rate of EGC is low. Hence, clinical application of SNNS for EGC might lead us to avoid unnecessary LN dissection, which could preserve the patient's quality of life after operation. The most ideal method of SNNS should allow secure and accurate detection of SLN, and real time observation of lymphatic flow during operation.

Current status and future perspectives on minimally invasive esophagectomy

Esophageal cancer has one of the highest malignant potentials of any type of tumor. The 3-field lymph node dissection is the standard procedure in Japan for surgically curable esophageal cancer in the middle or upper thoracic esophagus. Minimally invasive esophagectomy is being increasingly performed in many countries, and several studies report its feasibility and curability; further, the magnifying effect of the thoracoscope is another distinct advantage. However, few studies have reported that minimally invasive esophagectomy is more beneficial than open esophagectomy. A recent meta-analysis revealed that minimally invasive esophagectomy reduces blood loss, respiratory complications, the total morbidity rate, and hospitalization duration. A randomized study reported that the pulmonary infection rate, pain score, intraoperative blood loss, hospitalization duration, and postoperative 6-week quality of life were significantly better with the minimally invasive procedure than with other procedures. In the future, sentinel lymph node mapping might play a significant role by obtaining individualized information to customize the surgical procedure for individual patients' specific needs.