Lymphatic mapping and sentinel node biopsy in the colonic mesentery by Natural Orifice Transluminal Endoscopic Surgery (NOTES)

Sentinel lymph node mapping procedure in T1 colorectal cancer: A systematic review of published studies

OBJECTIVE

to investigate the role of sentinel lymph node mapping procedure in T1 Colorectal cancer.

BACKGROUND

The incidence of T1 Colorectal cancer is increasing thanks to screening and awareness campaigns. The issue concerning T1 is when to consider a local treatment curative or when it is necessary a radical resection. The histopathological features of resected polyps are able to predict the nodal spread but the value of specificity is increasingly a problem of these predictors. The sentinel lymph node procedure could be a solution.

METHODS

A systematic review was performed following PRISMA guidelines and using "sentinel node", "lymph nodes", and "colorectal cancer" as search terms in PubMed and Embase databases. References from included studies, review articles, and editorials were cross-checked. The risk of bias and quality of the included studies were assessed using the QUADAS-2 tool. The primary outcome was sentinel lymph node accuracy rate and the secondary outcome was sentinel lymph node detection rate for T1 Colorectal cancer.

RESULTS

A total of 12 studies (108 patients) met inclusion and exclusion criteria, 8 were monocentric cohort studies and 4 were multicentric cohort studies. The rate of sentinel lymph node accuracy in T1 colorectal cancer varies from 89% to 100%. Only 1 false negative was found. In 7 of these 12 studies (71 patients) the detection rate of T1 colorectal cancer was reported and showed a variation from 92% to 100%. Even in this case, only 1 case of failed procedure was found.

DISCUSSION

The literature on this topic agrees on that sentinel lymph node mapping, differently from breast cancer and melanomas should not be used for therapeutic purposes in colorectal cancer, but mainly to refine staging. The reason is the low sensitivity of this procedure with an accompanying high false negative rate. However, the data refers mainly to advanced stages of the disease because there are few data available on the earlier stages and in particular related to T1. Isolating the data related only to T1, the false negative rate seems to be very low. Additional studies are necessary, but a decisional role of sentinel lymph node mapping on the treatment of T1 Colorectal cancer is possible in the future.

Ex vivo sentinel lymph node mapping in colorectal cancer using a magnetic nanoparticle tracer to improve staging accuracy: a pilot study

AIM

Nodal status is the most important prognostic factor in colorectal cancer (CRC). Small occult metastases may remain undetected on conventional histopathological examination, potentially resulting in undertreatment. Ex vivo sentinel lymph node mapping (SLNM) can be used to improve the accuracy of nodal staging, but the currently used tracers suffer from drawbacks, which hamper implementation of the technique in routine clinical practice. Magnetic tracers are the optimal size for sentinel lymph node (SLN) retention and allow objective quantitative selection of SLNs; they therefore have great potential for SLNM in CRC. The study evaluates the feasibility of ex vivo magnetic SLNM and compares the performance of this technique with blue dye SLNM.

METHOD

Twenty-eight ex vivo SLNM procedures were performed in 27 histological node-negative patients with CRC using a magnetic tracer and blue dye. A magnetometer was used to select magnetic SLNs after formalin fixation of the CRC specimen. Both magnetic and blue SLNs were subjected to serial sectioning and immunohistochemical staining to reveal occult metastases.

RESULTS

At least one SLN was successfully identified in 27/28 (96%) and 25/28 (89%) of the cases with the magnetic technique and blue dye. Isolated tumour cells were detected in 10 patients. This was predicted with 100% sensitivity and accuracy using the magnetic technique, and with 91% sensitivity and 96% accuracy using the blue dye technique.

CONCLUSION

This study demonstrates that ex vivo magnetic SLNM is a feasible technique for use in routine clinical practice, improving nodal staging accuracy of CRC patients.

Current innovations in endoscopic therapy for the management of colorectal cancer: from endoscopic submucosal dissection to endoscopic full-thickness resection

Endoscopic submucosal dissection (ESD) is accepted as a minimally invasive treatment for colorectal cancer. However, due to technical difficulties and an increased rate of complications, ESD is not widely used in the colorectum. In some cases, endoscopic treatment alone is insufficient for disease control, and laparoscopic surgery is required. The combination of laparoscopic surgery and endoscopic resection represents a new frontier in cancer treatment. Recent developments in advanced polypectomy and minimally invasive surgical techniques will enable surgeons and endoscopists to challenge current practice in colorectal cancer treatment. Endoscopic full-thickness resection (EFTR) of the colon offers the potential to decrease the postoperative morbidity and mortality associated with segmental colectomy while enhancing the diagnostic yield compared to current endoscopic techniques. However, closure is necessary after EFTR and natural transluminal endoscopic surgery (NOTES). Innovative methods and new devices for EFTR and suturing are being developed and may potentially change traditional paradigms to achieve minimally invasive surgery for colorectal cancer. The present paper aims to discuss the complementary role of ESD and the future development of EFTR. We focus on the possibility of achieving EFTR using the ESD method and closing devices.

Sentinel node navigation surgery in patients with early gastric cancer

Clinical application of sentinel node (SN) mapping in patients with early gastric cancer has been a controversial issue for years. However, a recent meta-analysis and a prospective multicenter trial of SN mapping for early gastric cancer have shown acceptable SN detection rates and accuracy of determination of lymph node status. A dual-tracer method that utilizes radioactive colloids and blue dyes is currently considered the most reliable method for the stable detection of SNs in patients with early gastric cancer. However, new technologies such as indocyanine green infrared or fluorescence imaging might revolutionize the SN mapping procedures in gastric cancer. For early-stage gastric cancer such as cT1N0, for which a better prognosis can be potentially achieved through conventional surgical approaches, the establishment of individualized, minimally invasive treatments that may retain the patients' quality of life should be the next surgical challenge. Although there are many unresolved technical issues, laparoscopic SN biopsy with laparoscopic minimized gastrectomy or endoscopic mucosal resection/endoscopic submucosal dissection could be a promising strategy to achieve this goal.

Perirectal Oncologic Gateway to Retroperitoneal Endoscopic Single-Site Surgery (PROGRESSS): a feasibility study for a new NOTES approach in a swine model

INTRODUCTION

A transanal, posterior, retrorectal approach has been demonstrated as a feasible natural orifice transluminal endoscopic surgery (NOTES) total mesorectal excision (TME) procedure. The aim was to assess the feasibility of a transrectal approach with a completely retroperitoneal mobilization of the left colon and mesenteric vessels in an acute porcine model.

MATERIALS AND METHODS

Eight pigs were used. A purse-string suture was made 3 cm above the anal sphincter. Next, the retroperitoneal, perirectal space was entered with an endoscope through a single (or twin) anterior lateral, transrectal viscerotomy. A retroperitoneal tunnel was created using pneumodissection or endoscopically guided dissection to the inferior mesenteric artery (IMA). The IMA was skeletonized and lymph nodes retrieved using the IsisScope or other instruments. The IMA was divided with the Ligasure, clips, or ligature performed with the IsisScope. The rectum was dissected transanally in the "Holy" plane. After achieving mobilization using a completely retroperitoneal approach, the peritoneal attachments were then divided and the rectosigmoid specimen exteriorized through the anus. An explorative laparoscopy was then performed to evaluate the quality of the mobilization.

RESULTS

The procedure was successfully completed and the IMA correctly identified and ligated in all cases. In all but one case, no further mobilization was possible, even by a laparoscopic approach.

CONCLUSIONS

Perirectal oncologic gateway to retroperitoneal endoscopic single-site surgery for left-sided colonic resections using both flexible and rigid surgical endoscopic platforms was feasible and reproducible in an acute porcine model. This technique might represent a step toward pure NOTES left-sided colorectal procedures.

Interventional endoscopy and single incision surgery

The following on interventional endoscopy and single incision surgery contains commentaries on transluminal endoscopic esophageal surgery, flexible endoscopy, triangulation, advanced flexible operating platforms, experimental transesophageal procedures, and para- and intra-esophageal endoscopic surgery.

Natural orifice transluminal endoscopic surgery (NOTES) and colorectal cancer?

Surgical techniques and technologies are rapidly evolving. In the field of colorectal surgery the transanal video-assisted approach was introduced by Buess, 30 years ago, with transanal endoscopic microsurgery (TEM). In more recent years different techniques and technologies have been proposed, including natural orifice specimen extraction (NOSE), natural orifice transluminal endoscopic surgery (NOTES) and single-access surgery. Furthermore, a better understanding of the prognostic and risk factors of rectal cancer has allowed TEM to expand its indications to local resection of selected tumours, and more recently there have been proposals for sentinel node biopsy in colon and rectal cancer.

Ex vivo sentinel lymph node mapping in laparoscopic resection of colon cancer

AIM

The study examined the feasibility and potential benefit of ex vivo sentinel lymph node (SLN) mapping, including multilevel sectioning (MLS) and immunohistochemistry (IHC) in colon cancer patients undergoing laparoscopic colectomy. The secondary goals were (i) to identify patient and tumour characteristics that might influence the success of the SLN technique, (ii) to investigate the extent of lymphadenectomy required to encompass tumour-positive nonsentinel lymph nodes (NSLN) and (iii) to ascertain the association of SLN status with oncological outcomes.

METHOD

SLN mapping was performed after specimen extraction using 1% Isosulfan blue. The SLNs were analysed with H&E staining after MLS, and if negative, IHC was performed. NSLNs were grouped by distance either greater than or less than 4 cm from the tumour.

RESULTS

Seventy-one patients completed the study between 2003 and 2007. Using H&E with MLS, the accuracy of SLN mapping was 76%, sensitivity was 52% and the false-negative rate was 48%. Excluding patients with clinically positive lymph nodes resulted in a significant improvement in accuracy to 81% and decreased the false-negative rate to 30%. Furthermore, as the only positive NSLN > 4 cm from the tumour was grossly positive, SLN mapping with a 4-cm mesenteric cuff would have given 100% sensitivity in patients without macroscopically involved nodes.

CONCLUSIONS

SLN mapping may be of value in selected patients. It may be possible to accurately stage patients with a 4-cm cuff of mesentery, although further validation of this proposal is required.

Natural orifice transluminal endoscopic surgery (NOTES) in animals

Natural orifice transluminal endoscopic surgery (NOTES) is a modern technique of performing surgical procedures developed worldwide. In the last few years, series of NOTES operations were performed in animals and humans. This article describes some surgical procedures performed in animals with use of this new technique.

The ANUBIS™ project

The aims of the ANUBIS™ project developed in IRCAD-Strasbourg were to evaluate the concept and the potentialities of natural orifices transluminal endoscopic surgery (NOTES), to develop a specific instrumentation, to translate the research work into clinical settings and to provide education and training. To achieve these goals, an intensive collaboration was established between IRCAD, which comprises medical staff (surgeons, gastroenterologists, gynaecologists), computer scientists and robotics engineers, and industrial partners. Between 2005 and 2008, more than 400 experimental procedures were performed on inanimate models, ex-vivo tissues, animal models and human cadavers. Cholecystectomy was defined as the procedure that would realize the translation of experimental work into the clinical setting. The first human transvaginal cholecystectomy was performed at the end of the second year of the project. Transgastric cholecystectomy followed six months later. A new concept of therapeutic flexible endoscope (Anubiscope™, Storz Endoskope,Tutlingen, Germany) was developed, and different modalities of closure of the viscerotomies were elaborated. Implementation of the experimental program into the clinical setting and translation of technological research into a finalized industrial product were achieved thanks to a rigorous, extensive and stepwise study of the potentialities of NOTES. Education and training were organized and 500 participants attended the specific courses and hands-on sessions organized at IRCAD-EITS.

Hybrid transureteral natural orifice translumenal endoscopic nephrectomy: a feasibility study in the porcine model

BACKGROUND AND PURPOSE

Natural orifice approaches for nephrectomy have included access via the stomach, vagina, bladder, and rectum. The use of the ureter as a natural orifice for natural orifice translumenal endoscopic surgery (NOTES) nephrectomy has not been previously reported. The purpose of this study is to test the feasibility of transureteral laparoscopic NOTES nephrectomy.

MATERIALS AND METHODS

Three female farm pigs (29.2-30.8 kg) were placed into the lithotomy position. A cystoscopically placed extra-stiff guidewire was used to place a prototype dilating sheath into the left ureter. After dilation of the ureter and urethra, the sheath was exchanged for a 12-mm bariatric laparoscopic trocar. A 10.5-inch long 10-mm offset operating laparoscope with an internal 5-mm working port was used for the nephrectomy. One 2-mm and one 2/3-mm port were placed transabdominally to facilitate in situ morcellation. The kidney was cut into slices using the bipolar device and extracted via the ureteral port using the housing of a 12-mm bariatric stapling device.

RESULTS

All three transureteral nephrectomies were successfully completed. The total mean operative time was 220 minutes (range 113-346 min). Component portions of the procedure were: Ureteral access (mean 21 min), nephrectomy (mean 70 min), and kidney morcellation (mean 103 min). Mean estimated blood loss was 20 mL (range 5-50 mL). There were no intraoperative complications.

CONCLUSIONS

This nonsurvival porcine feasibility study demonstrates the successful performance of transureteral nephrectomy. This approach shows promise as a way to decrease the invasiveness of NOTES nephrectomy by using the ureteral orifice as an access site.

Natural orifice transluminal endoscopic surgery and localized resection for colorectal neoplasia

Modern methods of surgical intervention have the potential to provide effective, definitive management of early stage colorectal neoplasia by truly minimally invasive means. Margin-free clearance of early colonic neoplasia from within the intestinal lumen can already now be effected by endoscopic submucosal dissection in the colon and transluminal endoscopic microsurgery (TEM) in the rectum. Natural orifice transluminal endoscopic surgery (NOTES) offers the potential for providing transmural, full thickness excision as TEM does but at sites in the colon proximal to the rectum. The next conceptual advance required to make this practice an effective reality lies in evolving surgical regional staging strategies to effectively partner localized resective approaches and allow their deployment as definitive curative therapy. As the most compelling modality for nodal status ascertainment in the absence of lymphatic basin excision for other malignant disease processes, it seems timely to reconsider sentinel node biopsy in cancer of the colon and rectum. Whether by this means or indeed any other, such an ability to confidently identify patients with node negative disease would allow nascent innovative techniques flourish as definitive management for confined (N0) T1 and T2 cancers and so allow the application of available advanced technology for clinical benefit. Conversely, the development of a specific clinical niche for NOTES (whether, as here, for full thickness localized colonic excision or nodal staging alone) would greatly benefit the evolution and incorporation of this surgical strategy into clinical care paradigms.

NOTES: The question for minimal resection and sentinel node in early gastric cancer

Surgical therapy for gastric cancer involves both removal of the cancer lesion and complete lymph node dissection. Natural orifice transluminal endoscopic surgery (NOTES) is considered to represent the next revolution in surgery. Many surgeons and endoscopists believe that NOTES may be a superior alternative for early gastric cancer treatment. Sentinel node (SN) navigation surgery for gastric cancer: Single institution results of SN mapping for early gastric cancer are increasingly being considered acceptable. Furthermore, a major large-scale clinical trial of SN mapping for gastric cancer has recently been completed by The Japan Society of SN Navigation Surgery study group. They reported false negative rate of 7.0% while the sensitivity of metastasis detection based on SN status was 93%. Combination of SN biopsy and NOTES: This concept was first described by Cahill et al who proved the feasibility of lymphatic mapping and SN biopsy by NOTES. Lymphatic channel filling was immediately observable via the intraperitoneal optics. Partial resection of the stomach by hybrid NOTES: Several centers have already reported gastrectomy assisted by NOTES using the transvaginal route. However, the main problem of full-thickness resection of gastric wall remains endoscopic gastric closure. Establishing an endoscopic suturing method would be an important step toward expanding potential indications. NOTES is met with both enthusiasm and skepticism but will gain its own place as human creativity eventually provides solutions to its technical limitations. In the near future, NOTES can evolve the capacity to complement the existing armamentarium for gastric cancer surgery.

Transgastric cholecystectomy: From the laboratory to clinical implementation

After the first report by Kalloo et al on transgastric peritoneoscopy in pigs, it rapidly became apparent that there was no room for an under-evaluated concept and blind adoption of an appealing (r)evolution in minimal access surgery. Systematic experimental work became mandatory before any translation to the clinical setting. Choice and management of the access site, techniques of dissection, exposure, retraction and tissue approximation-sealing were the basics that needed to be evaluated before considering any surgical procedure or study of the relevance of natural orifice transluminal endoscopic surgery (NOTES). After several years of testing in experimental labs, the revolutionary concept of NOTES, is now progressively being experimented on in clinical settings. In this paper the authors analyse the challenges, limitations and solutions to assess how to move from the lab to clinical implementation of transgastric endoscopic cholecystectomy.

Natural orifice transluminal endoscopic surgery--here and now

Natural Orifice Transluminal Endoscopic Surgery (NOTES) has captured the attention of physicians and patients alike. Although clinical experience remains limited as technological capacity lags someway behind concept, this revolutionary approach is already prompting reassessment of conventional surgical dogma. Indeed, this very aspect may in fact represent the greatest legacy of current endeavour aimed at progressing natural orifice intervention as the biological insights so gleaned may then be used to help hone standard operations further towards perfection. As a corollary, rather than viewing it as a mere means of reformatting laparoscopic operation without the abdominal wall access component, NOTES should be investigated fully from the perspective of how it may complement (rather than compete with) current conventional techniques. In this way patients may in due course be allowed benefit by selection of the procedure of 'best fit' from an expanded array of surgical interventions. A clear focus on identifying specific clinical niches that are currently imperfectly addressed would also considerably advance the rationale for new surgical innovations such as NOTES and allow them to be engineered in the directions most likely to result in therapeutic advance. Thus while NOTES approaches for operations for neoplasia of the colon and even rectum clearly require more nuanced deliberation and care than does for example cholecystectomy for uncomplicated cholelithiasis, the gain from such investment seems likely to more considerably aid both the development and stature of NOTES as well as providing the greater likelihood of clinical progress for our patients.

Intraperitoneal virtual biopsy by fibered optical coherence tomography (OCT) at natural orifice transluminal endoscopic surgery (NOTES)

INTRODUCTION

Fibered optical coherence tomography (OCT) in conjunction with natural orifice transluminal endoscopic surgery (NOTES) could provide a facility for rapid, in situ pathological diagnosis of intraperitoneal tissues in a truly minimally invasive fashion.

MATERIALS AND METHODS

A large porcine model was established to test this hypothesis. A standard double channel gastroscope (Olympus) was used to achieve a transgastric access to the peritoneum and initiate the pneumoperitoneum. Magnetic retraction was used to display the sigmoid colon along with its mesentery. A commercially available fibered OCT probe (NIRIS system, Imalux) was inserted via a working channel of the gastroscope and used to assess intraperitoneal tissues. Separately, OCT images of human tissue specimens ex vivo were contrasted with representative standard histopathological slides.

RESULTS

Intraperitoneal OCT provided clear real-time images of both the serosal and muscularis propria mural layers as well as the submucosal-muscularis interface. Examination of mesenteric lymph nodes (including sentinel nodes) allowed visualization of their subcapsular sinus. Comparison of representative cross-sections however failed to evince sufficient resolution for confident diagnosis.

CONCLUSION

This approach is technically feasible and, if the technology is advanced and proven accurate in human patients, could potentially be used to individualize operative extent prior to definitive resection.

Sentinel node procedure of the sigmoid using indocyanine green: feasibility study in a goat model

BACKGROUND

The sentinel lymph node (SLN) procedure alter the strategy for the treatment of patients with colon cancer. New techniques emerge that may provide the surgeon with a tool for accurate intraoperative detection of the SLNs.

METHODS

An SLN procedure of the sigmoid was used in six goats. During laparoscopy, the near-infrared dye indocyanine green (ICG) was injected into the subserosa of the sigmoid via a percutaneously inserted needle during four experiments and in the submucosa during colonoscopy in two experiments. After injection, the near-infrared features of a newly developed laparoscope were used to detect the lymph vessels and SLNs. At the end of the procedure, 2 h after injection, all the goats were killed, and autopsy was performed. During postmortem laparotomy, the sigmoid was removed and used for confirmation of ICG node uptake.

RESULTS

In all the procedures, the lymph vessels were easily detected by their bright fluorescent emission. In the first two experiments, no lymph nodes were detected. In the subsequent four experiments, human serum albumin was added to the ICG solution before injection to enable better lymph node entrapment. In all four experiments, at least one bright fluorescent lymph node was found after the lymph vessels had been tracked by their fluorescent guidance. The mean time between injection and SLN identification was 10 min. In two cases, the SLNs were located up to 5 mm into the fat tissue of the mesentery and were not seen by regular vision of the laparoscope. By switching on the near-infrared features of the scope, a clear bright dot became visible, which increased in intensity after opening of the mesentery.

CONCLUSION

The SLN procedure for the sigmoid using near-infrared laparoscopy in the goat is a very promising technique. Achievements described in this report justify a clinical trial on the feasibility of ICG-guided SLN detection in humans.

Sentinel node biopsy for the individualization of surgical strategy for cure of early-stage colon cancer

INTRODUCTION

The requirement for nodal analysis currently confounds the oncological propriety of focused purely endoscopic resection for early-stage colon cancer and complicates the evolution of innovative alternatives such as natural orifice transluminal endoscopic surgery (NOTES) and its hybrids. Adjunctive sentinel node biopsy (SNB) deserves consideration as a means of addressing this shortfall.

METHODS

Data from two prospectively maintained databases established for multicentric studies of SNB in colon cancer that employed similar methodologies were pooled to establish technique potency selectively in T1/T2 disease (both overall and under optimized conditions) and to project potential clinical impact.

RESULTS

Of 891 patients with T1-4, M0 intraperitoneal colon cancer, 225 had T1/T2 disease. Sentinel nodes were either not found or were falsely negative in 18 patients with T1/T2 cancers (8%) as compared with 17% (112/646) in those with T3/T4 disease (P = 0.001). Negative predictive value (NPV) in the former exceeded 95%, while sensitivity [including immunohistochemistry (IHC)] was 81%. In the 193 patients with T1/T2 disease recruited from those centers contributing >22 patients, sensitivity was 89% and NPV 97%. Thus, in this cohort, SNB could have correctly prompted localized resection (obviating en bloc mesenteric dissection) in 75% (144) of patients, including 59 with T1 lesions potentially amenable to intraluminal resection alone as their definitive treatment. Forty-four patients (23.4%) would still have conventional resection, leaving three patients (1.6% overall) understaged (11% false-negative rate).

CONCLUSION

These findings support the further investigation of SNB as oncological augment for localized resective techniques. Specific prospective study should pursue this goal.

Supplementation of endoscopic submucosal dissection with sentinel node biopsy performed by natural orifice transluminal endoscopic surgery (NOTES) (with video)

BACKGROUND

Endoscopic submucosal dissection (ESD) is proving to be effective for the resection of selected early gastric and colon cancers. Its application and appropriateness could be extended if a means of determining lymphatic dissemination without recourse to a conventional operation could be provided.

OBJECTIVE

To demonstrate the feasibility of companion sentinel node biopsy (SNB) by natural orifice transluminal endoscopic surgery (NOTES) concurrent with intraluminal ESD in both the sigmoid colon and stomach.

DESIGN

Acute porcine model.

INTERVENTION

Arbitrarily selected mucosal foci were targeted for combined NOTES-SNB and ESD in the sigmoid and stomach of 2 separate anesthetized animals. NOTES peritoneal access was obtained either transgastrically or transvaginally. A second intraluminal endoscope was passed either orally or rectally, as appropriate, to perform submucosal injection for lymphatic mapping under direct vision of the NOTES endoscope. This endoscope then identified the first-order draining (sentinel) nodes and allowed their excisional biopsy. The sigmoid was retracted by magnetic assistance as required, while torque of an intraluminal gastroscope manipulated the stomach. After retrieval of the nodes, 1-cm and 1.5-cm specimens were resected from the sigmoid and stomach, respectively, by conventional ESD. At procedure end, necropsy was performed.

RESULTS

All sentinel nodes were identified, underwent biopsy, and were retrieved intact. ESD was subsequently readily performed without complication. SNB completeness and ESD quality were confirmed postprocedure.

LIMITATIONS

Experimental model with limited sample size.

CONCLUSIONS

Although not yet appropriate for human use, this proposal merits serious consideration as a potential means of augmenting the effectiveness and appropriateness of ESD techniques for GI neoplasia.

Multimedia article. Combined sentinel node biopsy and localized sigmoid resection entirely by natural orifice transluminal endoscopic surgery: a new challenge to the old paradigm

INTRODUCTION

We demonstrate localized sigmoidectomy with sentinel node biopsy performed entirely via natural orifice transluminal endoscopic surgery in a porcine model (see Video, Supplemental Digital Content 1, http://links.lww.com/A1170).

METHODS

To perform transluminal endoscopic sentinel node biopsy in the sigmoid mesocolon, a conventional double-channel gastroscope created both the gastrotomy and pneumoperitoneum enabling peritoneoscopy. The sigmoid colon was exposed by an intracolonic magnet under extracorporeal control while intraluminal colonoscopy performed lymphatic mapping via submucosal injection of methylene blue dye. After searching the mesocolon for blue-stained lymph channels, the sentinel nodes were resected and retrieved by the intraperitoneal fiberscope. Immediate thereafter localized sigmoidectomy was performed via an additional transcolonic access just above the rectosigmoid junction. With the circular stapler anvil placed early into the proximal colon, mesenteric dissection and proximal transection were performed using conventional laparoscopic instruments worked through a long standard trocar passed transanally through the colotomy. The specimen was delivered per ano (pull-through technique) and the distal margin cross-stapled extracorporeally, including the colotomy within the specimen. Stapled intestinal anastomosis was fashioned by passing a circular stapler transanally (thus returning the rectal stump to its anatomic position) and mating it with the in situ anvil. The gastrotomy was closed as previously described.

RESULTS

The operative duration was 31.4 minutes and technical success was readily achieved. Patency and integrity of the anastomosis was confirmed by sigmoidoscopy.

CONCLUSION

Oncologically propitious surgery for germinal colonic neoplasia may be encompassed by natural orifice transluminal endoscopic surgery. This provocative proposal challenges the conventional treatment paradigm for early stage colonic neoplasia although much further validation of the concepts involved is required.

Staging of gynaecological malignancies by natural orifice transluminal endoscopic surgery (N.O.T.E.S.)

Gynaecological malignancies are most often diagnosed and staged by surgery. With the expanding evidence of efficacy and benefit of neoadjuvant treatments, such tumor confirmation and assessment should be ideally done with the least associated morbidity. Thus sentinel node biopsy has already been proposed for selected indications so that the morbidity associated with formal lymphadenectomy could be avoided in those patients without nodal metastases. The era of natural orifice transluminal endoscopic surgery (N.O.T.E.S.) heralds an operative methodology of 'least invasiveness' that could be useful in gynaecological cancer. In this article, we present an overview of the staging of gynaecological malignancies with a focus on the potential applications and benefits that N.O.T.E.S. may provide in this field. In particular, we believe that performing sentinel lymph node dissection with N.O.T.E.S. could associate the low morbidity rate of the former technique with the minimal invasiveness of the latter one and therefore consolidate the potential of this technique.

N.O.T.E.S.: the progression of a novel and emerging technique

Natural Orifice Transluminal Endoscopic Surgery (NOTES) is the latest and perhaps most significant innovation in surgery since Phillipe Mouret of France performed the first laparoscopic cholecystectomy in 1987. This new "minimum-invasive" concept that promises scar-free surgery is steadily gathering momentum. It is another milestone in our quest to eliminate surgical trauma, speed patient recovery time and decrease surgical wound-related complications. On 22 July 2005, the Natural Orifice Surgery Consortium for Assessment and Research (NOSCAR) published a white paper highlighting the barriers to NOTES development, which included the need for appropriate selection of access points, effective closure of the enterotomy site, innovative tools, stable platforms and improved endoscopic orientation. These are just some of the many issues that need to be resolved before the NOTES concept and technique could become a common feature of modern surgery. The publication of the white paper ushered in the beginning of multiple research projects using animal models to test the application of NOTES and its newly developed instruments. The success in animal models was followed by several highly selected successful human trials. National and international surgical innovation departments should now be created where medical industry personnel including inventors, designers and engineers can work together with the medical and surgical providers to address all the limitations affecting NOTES progress.

Could lymphatic mapping and sentinel node biopsy provide oncological providence for local resectional techniques for colon cancer? A review of the literature

BACKGROUND

Endoscopic resectional techniques for colon cancer are undermined by their inability to determine lymph node status. This limits their application to only those lesions at the most minimal risk of lymphatic dissemination whereas their technical capacity could allow intraluminal or even transluminal address of larger lesions. Sentinel node biopsy may theoretically address this breach although the variability of its reported results for this disease is worrisome.

METHODS

Medline, EMBASE and Cochrane databases were interrogated back to 1999 to identify all publications concerning lymphatic mapping for colon cancer with reference cross-checking for completeness. All reports were examined from the perspective of in vivo technique accuracy selectively in early stage disease (i.e. lesions potentially within the technical capacity of endoscopic resection).

RESULTS

Fifty-two studies detailing the experiences of 3390 patients were identified. Considerable variation in patient characteristics as well as in surgical and histological quality assurances were however evident among the studies identified. In addition, considerable contamination of the studies by inclusion of rectal cancer without subgroup separation was frequent. Indeed such is the heterogeneity of the publications to date, formal meta-analysis to pool patient cohorts in order to definitively ascertain technique accuracy in those with T1 and/or T2 cancer is not possible. Although lymphatic mapping in early stage neoplasia alone has rarely been specifically studied, those studies that included examination of false negative rates identified high T3/4 patient proportions and larger tumor size as being important confounders. Under selected circumstances however the technique seems to perform sufficiently reliably to allow it prompt consideration of its use to tailor operative extent.

CONCLUSION

The specific question of whether sentinel node biopsy can augment the oncological propriety for endoscopic resective techniques (including Natural Orifice Transluminal Endoscopic Surgery [NOTES]) cannot be definitively answered at present. Study heterogeneity may account for the variability evident in the results from different centers. Enhanced capacity (perhaps to the level necessary to consider selective avoidance of en bloc mesenteric resection) by its confinement to only early stage disease is plausible although not proven. Specific study of the technique in early stage tumors is clearly essential before proffering this approach.