Validation of sentinel lymph node (SLN) mapping (M) in colon cancer (Cca) over three continents: An international experience

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Background: Lymph node (LN) status is the most important prognostic factor in colon cancer (Cca). In various trials, the average nodal positivity of conventional surgery in Cca is about 33%. Ultrastaging of SLNs results in higher and more accurate nodal staging of patients (pts) with Cca. However, some recent publications of SLNM in Cca have shown variable results with differing conclusions. Hence, prospective data from 3 continents were analyzed to study the international experience of SLNM in Cca. Methods: Only centers with experience of 40 or more cases of SLNM in Cca were included in the study. SLNM was performed by peri-tumoral injections of 1–3 ml of 1% lymphazurin. First 1–4 blue nodes marked as SLNs were ultrastaged by multilevel microsections for H&E and IHC. Data for calculating the success rate, accuracy, skip metastases (mets), sensitivity, negative predictive value; nodal positivity and upstaging were collected from each center. Results: Our study included a total of 1,216 Cca pts from 9 centers over 3 continents. SLNM was successful in 92.9% pts ( Table 1 ). The average number of LN/pt was 18.5 and the average number of SLN/pt was 2.7. The overall sensitivity, accuracy rate and negative predictive value were 78.3%, 89.4% and 82.8% respectively. Nodal mets were found in 52.9% pts. Of these, SLNs were the exclusive site for mets in 30.1% pts while 18.3% pts were upstaged by SLNM. Skip mets were seen in 21.7% pts (range 9.5% - 44.1%). Conclusions: SLNM is highly successful in Cca when performed by experienced surgeons worldwide. Nodal positivity was found to be much higher in pts undergoing SLNM compared to conventional surgery. Upstaged pts may benefit from adjuvant chemotherapy. Though the variation of skip mets was wide, the clinical impact of skip mets in Cca is negligible compared to that in melanoma and breast cancer, since all pts undergo standard lymphadenectomy and all node positive pts (true +ve & skip mets) are usually treated with adjuvant chemotherapy.

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No significant financial relationships to disclose.

Benefits, limitations and pitfalls of sentinel lymph node (SLN) mapping (M) for colorectal carcinoma (CRCa): A multicenter trial

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Background: Clinical application of SLNM in CRCa patients (pts) is controversial due to the variable results in the literature for its success, skip metastases (mets) and accuracy. Hence prospective data from 5 institutions were analyzed to identify the factors associated with failure and skip mets in CRCa pts undergoing SLNM. Methods: SLNM was performed by peri-tumoral injections of 1–3 ml of 1% lymphazurin subserosally. First 1–4 blue nodes marked as SLNs were examined by 4 sections with H & E and 1 for cytokeratin. Rate of failure and skip mets rate along with age, sex, tumor site, size, grade, T & N stages were analyzed. Results: 549 consecutive CRCa pts underwent SLNM; 453 colon (C) and 96 rectal (R) pts. M: F ratio was 48%: 52% and median age of 72 years. The average no. of LNs was 14.5. SLNM failed in 1% of C and 8% of R pts ( Table ). Of the 8 R failures, 7 had neoadjuvant therapy. No correlation was found between failure, size or T-stage. Overall nodal positivity (+ve) rate was 48%. Of the 466 invasive CRCa pts with successful SLNM, rate of skip mets was 7% in C and 4% in R. Age, sex, grade and neoadjuvant therapy had no correlation with skip mets. Of 28 skip mets pts, 79% had tumors >3cm and 93% had advanced (T3, T4) tumors. Higher skip mets also was found in the transverse colon tumor. The success, accuracy, and sensitivity rates were 98%, 95%, and 88% respectively. Of node +ve pts, 47% had mets found only in the SLNs. SLNM upstaged 35% of C and 36% of R pts with micromets. Conclusions: In CRCa, SLNM is highly successful and accurate in predicting the presence or absence of nodal mets. Submucosal fibrosis of the lymphatics due to neoadjuvant therapy may result in higher failure rates for R pts. Skip mets are higher in transverse C tumors and increase in frequency as the T-stage increases. Pts upstaged by SLNM may benefit from adjuvant chemotherapy.

[Table: see text]

No significant financial relationships to disclose.

Compliance of the L5-S1 spinal unit: a comparative study between an unconstrained and a partially constrained system

A comparison between an unconstrained and a partially constrained system for in vitro biomechanical testing of the L5-S1 spinal unit was conducted. The objective was to compare the compliance and the coupling of the L5-S1 unit measured with an unconstrained and a partially constrained test for the three major physiological motions of the human spine. Very few studies have compared unconstrained and partially constrained testing systems using the same cadaveric functional spinal units (FSUs). Seven human L5-S1 units were therefore tested on both a pneumatic, unconstrained, and a servohydraulic, partially constrained system. Each FSU was tested along three motions: flexion-extension (FE), lateral bending (LB) and axial rotation (AR). The obtained kinematics on both systems is not equivalent, except for the FE case, where both motions are similar. The directions of coupled motions were similar for both tests, but their magnitudes were smaller in the partially constrained configuration. The use of a partially constrained system to characterize LB and AR of the lumbosacral FSU decreased significantly the measured stiffness of the segment. The unconstrained system is today's "gold standard" for the characterization of FSUs. The selected partially constrained method seems also to be an appropriate way to characterize FSUs for specific applications. Care should be taken using the latter method when the coupled motions are important.

Navigation an der Brust- und Lendenwirbelsäule mit dem 3D-Bildwandler

The mobile SIREMOBIL Iso-C(3D) C-arm (Siemens, Erlangen, Germany) is the first device permitting intraoperative, three-dimensional representation of bone structures. A high-resolution, isotropic 3D data cube in the isocenter with sides of approximately 12 cm is calculated simultaneously. The SIREMOBIL Iso-C(3D) is linked to the navigation system. This makes it possible to transfer the generated 3D data directly to the linked navigation system without the need for surgeon-dependent registration. In this prospective clinical trial, we evaluated the accuracy of pedicle screw placement using this device. In 61 patients, a total of 302 pedicle screws were placed. Only in five cases (1.7%) were misplacements of > or =2 mm shown in postoperative control CT. The average fluoroscopy time was 1.28+/-0.56 min, and the average operative duration was 103.26+/-23.3 min. There were no postoperative neurological complications in any of the 30 patients. From these data, we conclude that Iso-C(3D) navigation is a very accurate method for the placement of pedicle screws.

Technical details of sentinel lymph node mapping in colorectal cancer and its impact on staging

BACKGROUND

Sentinel lymph node (SLN) mapping for melanoma and breast cancer has greatly enhanced the identification of micrometastases in many patients, thereby upstaging a subset of these patients. The purpose of this study was to see if SLN mapping technique could be used to identify SLNs in colorectal cancer and to assess its impact on pathological staging and treatment.

METHODS

At the time of surgery, 1 ml of Lymphazurin 1% was injected subserosally around the tumor without injecting into the lumen. The first to fourth blue nodes identified were considered the SLNs, which have the highest probability to contain metastases. A standard oncological resection of the bowel was then performed. Multilevel microsections of the SLNs, including a detailed pathological examination of the entire specimen, was performed.

RESULTS

SLN was successfully identified in 85 (98.8%) of 86 patients. In 85 patients, there were 1,367 (16 per patient) lymph nodes examined, of which 140 (1.6 per patient) were identified as SLNs. In 53 (95%) of 56, of whom the SLNs were without metastases (negative), all other non-SLNs also were negative. In 29 (34% of 85) patients, SLNs were positive for metastases; in 14 of the 29 patients, other non-SLNs also were positive in addition to the SLNs. In the other 15 of the 29 patients (18% of 85 patients), SLNs were the only site of metastases, and all other non-SLNs were negative. In 7 patients (8.2% of 85 patients), micrometastases were identified only in 1 or 2 of the 10 sections of a single SLN. In five of seven patients, such micrometastases were detected by hematoxylin and eosin staining and immunohistochemistry; in the other two patients, it was detected only by immunohistochemistry. In patients with negative SLNs, the rate of occurrence of micrometastases in non-SLNs was 5 (0.4%) of 1,184 lymph nodes.

CONCLUSIONS

SLN mapping can be performed easily in colorectal cancer patients, with an accuracy of more than 95%. The identification of submicroscopic lymph node metastases by this technique may have upstaged these patients (18%) from stage I/II to stage III disease, who may then benefit from further adjuvant chemotherapy.