[PDF] Methylene Blue–Assisted Lymph Node Dissection in Colon

View - Download Methylene Blue–Assisted Lymph Node Dissection in Colon

Previous PDF

Next PDF

Am J Clin Pathol 2008;130:913-919 913

913 DOI: 10.1309/AJCPVAPB5APABJNX 913

© American Society for Clinical Pathology

Anatomic Pathology / Methylene Bl u e-Assisted lyMp h no d e stAg i n g Methylene Blue-Assisted Lymph Node Dissection in Colon Specimens

A Prospective, Randomized Study

1

Therese G. Kerwel, MD,

2 1

Daniel Oruzio, MD,

3

Hans M. Arnholdt, MD,

1 2

Matthias Anthuber, MD,

2 and Hanno Spatz, MD 2 Key Words: Methylene blue; Fat clearance; Colon cancer; Lymph node staging

DOI: 10.1309/AJCPVAPB5APABJNX

Recently, we introduced ex vivo intra-arterial

methylene blue injection into the inferior mesenteric artery as a novel method to improve lymph node (LN)

harvest in rectal cancer. We have now adapted this method to the other segments of the colon. A total of

60 cases were enrolled. Primary LN dissection was

followed by fat clearance and a secondary dissection. The mean ± SD primary LN harvest differed highly significantly with 35 ± 18 and 17 ± 10 LNs in the methylene blue-stained and unstained groups,

respectively. Primary insufficient LN harvest occurred in 8 cases of the unstained group and in only 1 case of

the methylene blue-stained group (P = .0226). After secondary dissection, upstaging was seen exclusively in the unstained group. The time/LN ratio differed significantly with 0.9 and 0.6 min/LN in the unstained and methylene blue-stained groups, respectively. Intra- arterial methylene blue injection is recommended as a routine technique in the histopathologic study of colon cancer.

Lymph node (LN) assessment is a crucial part of the histopathologic staging of colon cancer. Stage I and II cases

need no further therapy after oncologic resection. In contrast, stage III cancers, which are defined by LN metastases, are generally treated with adjuvant chemotherapy. 1,2

The 5-year

survival rates drop from 83% for stage II to 60% for stage III cancers. 3 This decrease highlights the importance of accurate LN assessment. Despite that, the optimal method for staging LNs continues to be debated. There is a lack of consensus in the literature on how many LNs should be assessed.4-7 To further complicate the issue, multiple advanced techniques for LN staging have been developed; however, their roles are not clearly defined. Other strategies include techniques such as fat clearance to increase the LN harvest 8-10 and newer methods that are used to improve the detection rate of metastases. Recent developments include techniques such as sentinel node biopsy,

11 immunohistochemical analysis, and

polymerase chain reaction. 8,12

Widespread use of these tech-

niques, however, is limited by an increase in time effort, costs, and the need for special facilities. Despite an emphasis on accurate LN staging, the reality is that the minimal 12 LNs as recommended by the International Union Against Cancer for a colorectal specimen is often not achieved in practice.

7,13-15

We recently published a pilot study with a novel tech- nique to increase LN harvest in rectal cancer by intra-arterial injection of methylene blue.

16 This technique was originally

developed to assess the integrity of the mesorectal fascia after total mesorectal resection. 17

During routine assessment of

such rectal specimens, we observed that LNs were stained blue within the fat and, therefore, were very easy to detect. After demonstrating improved LN harvests in rectal specimens, we

adapted this method for the other colon segments. The present Downloaded from https://academic.oup.com/ajcp/article/130/6/913/1760355 by guest on 22 September 2023

914 Am J Clin Pathol 2008;130:913-919

914 DOI: 10.1309/AJCPVAPB5APABJNX

© American Society for Clinical Pathology

study was performed to compare this novel method with the standard technique in a prospective and randomized manner, with special consideration of the time and technical aspects.

Materials and Methods

We prospectively enrolled 60 consecutive cases in 9 months and randomized them to the methylene blue-stained or the unstained group. The inclusion criterion was a curative resection of any part of the colon and the upper rectum for histologically proven or suspected malignancies. Exclusion criteria were palliative and emergency resections. All specimens were brought to pathology immediately after resection in a fresh and unfixed state. Depending on the result of randomization, the specimens were immediately opened, washed, and stretch-fixed in 10% buffered formalin overnight or injected with methylene blue followed by fixa- tion Figure 1. Injection was carried out by 2 pathologists in the department (B.M. and H.J; B.M. had previous experience with approximately 30 specimens, and H.J. had no experience at the start of the study). The learning curve is very small for left colon specimens and requires a few cases for right colon specimens. For the injection, the main artery was identified and the clip or ligature was cut off. The artery was opened longitudinally for a length of about 10 mm to facilitate can- nulation with a standard 16- or 17-gauge intravenous catheter without a steel mandrin. To seal the catheter in the artery, a clamp was fixed beside the artery in parallel orientation. The success of the gentle injection of 15 to 20 mL of methylene blue solution (50 mg diluted with 0.9% saline; ratio, 1:3) can be observed by instantaneous blue staining of the specimen's serosal layer Image 1. The time for this procedure was mea- sured and the performance judged in 4 categories: (1) easy, (2) minor difficulties, (3) major difficulties but successful, or (4) not successful. Following injection, the specimens were handled in the same way as in the unstained group. After fixing, representative sections of the tumor region were cut out and embedded. The paracolic fat was then dis- sected. Larger LNs detectable by palpation were cut out immediately. Next, the fat was sliced and stretched to reach thin layers. The cut surfaces were then screened for LNs. LNs in the methylene blue-stained group were stained blue and, therefore, easy to detect (Image 1). A second LN preparation was done in all cases after fat dehydration with increasing concentrations of isopropanol (70% and 100%) and clearance in xylene. Time for the primary and secondary LN preparation was measured. After paraffin embedding, 3-µm thin sections were cut and stained with H&E. The slices were then screened for metastases. Maximum diameters of LNs and metastases were measured using a digital camera with a calibrated soft- ware system (Progress C10, Jenoptik, Jena, Germany) and grouped into 6 categories (<1 mm, 1-4 mm, >4-6 mm, >6-8 mm, >8-10 mm, and >10 mm). The significance of differences between groups was calculated by using the Mann-Whitney rank sum test for mea- sured values with failed normality and the 2 test for clinical characteristics. All data were processed using SigmaStat 3.5 software (Systat Software, Richmond, CA). A P value of less than .05 was considered significant.

Results

Comparison of group characteristics Table 1 showed a nonsignificant higher frequency of male sex (23 vs 16) and locally advanced cases (24 vs 19) in the methylene blue- stained group. The other parameters, including the distribu- tion of cancer location, were well balanced.

Methylene Blue Injection

Methylene blue injection was successfully performed in all but 1 case. An extravasate of the dye caused by an arterial leakage occurred in a right hemicolon specimen. Because the staining of the LNs failed, the case was excluded from further analysis. The conventional investigation was not influenced negatively. Minor difficulties arose in 3 right hemicolon resections,

2 sigmoid specimens, and 1 left hemicolon specimen. The

difficulties were due to problems with finding the main artery

Randomization

Formalin fixing

Lymph node dissection (primary)

Fat clearance

Lymph node dissection (secondary)Methylene

InjectionUnstainedPathology

specimen in fresh stat e Figure 1 Algorithm of different steps. The clock indicates

time measurements.Downloaded from https://academic.oup.com/ajcp/article/130/6/913/1760355 by guest on 22 September 2023

Am J Clin Pathol 2008;130:913-919 915

915 DOI: 10.1309/AJCPVAPB5APABJNX 915

© American Society for Clinical Pathology

Anatomic Pathology / originAl Ar t i c l e

CD EF AB Image 1 Methylene blue injection technique in sigmoid colon specimen and staini ng results. A, Longitudinal opening of the

artery over 10 mm after removing the clip or the ligature. B, Cannulation of the artery using a 16-gauge intravenous catheter

without steel mandrin. C, Advancing the catheter and sealing in the artery with a clamp that is fixed beside the artery in

parallel orientation. D, Connecting the syringe with the catheter and injection of the methylen e blue solution. The serosal layer

turns blue during the injection. E, Two blue-stained lymph nodes on cut surface with diameter of 2-3 mm (

arrows). F, Further

improved visibility of blue-stained lymph nodes after fat clearance.Downloaded from https://academic.oup.com/ajcp/article/130/6/913/1760355 by guest on 22 September 2023

916 Am J Clin Pathol 2008;130:913-919

916 DOI: 10.1309/AJCPVAPB5APABJNX

© American Society for Clinical Pathology

and inhomogeneous staining results. Because of the inhomo- geneous staining, a second injection was done into a distal artery. Major problems occurred in only 1 case in which the injection procedure was prolonged and took 7 minutes in a right hemicolon specimen.

Primary LN Dissection

The mean ± SD numbers of LNs in the primary dissec- tion differed highly significantly (P < .001) with 35 ± 18 LNs (range, 10-101) in the methylene blue-stained group and

17 ± 10 LNs (range, 1-42) in the unstained group Figure

2. The greatest differences were seen in the 3 smallest size

groups (<6 mm) with total LN numbers of 832 and 391 in the unstained and methylene blue-stained groups, respectively (P < .001) Figure 3. Insufficient LN harvest with less than

12 detected LNs occurred significantly (P = .026) more often

in the unstained group, with 8 cases compared with only 1 case in the methylene blue-stained group. Two of these cases were T stage 1, 2 were stage 2, and the remaining 5 cases were stage 3. Metastases were found in 8 and 10 cases of 28 malignant cases in the methylene blue-stained and unstained groups, respectively. Of these total 18 cases, 3 (17%) showed insufficient LN harvest. The total numbers of metastasized LNs were 34 and 30 in the methylene blue-stained and unstained groups, respectively. Of the metastasized LNs, 62% of the methylene blue-stained group and 57% of the unstained group were smaller than 6 mm. No metastases were found in

LNs smaller than 1 mm.

Secondary LN Dissection

The mean ± SD additional LN yield after fat clearance was 8 ± 7 (range, 0-28) and 5 ± 4 (range, 0-18) in the meth- ylene blue-stained and unstained groups, respectively (P > .05) (Figure 2). Additional metastases were found in 1 case in the methylene blue-stained group compared with 4 cases in the unstained group. Upstaging occurred exclusively in the unstained group. A total of 3 cases were upstaged: 1 case changed from N0 to N1, and 2 cases were upstaged form N1quotesdbs_dbs26.pdfusesText_32

[PDF] Bleue judo - Anciens Et Réunions

[PDF] Bleuet nain Avertissement N° 7 – 16 juin 2015 ALTISE

[PDF] Bleyle - Langenargen

[PDF] Blick am Abend National - Anciens Et Réunions

[PDF] Blick auf Oberleuken

[PDF] Blick in d speicher Volksbanken der Region wollen

[PDF] Blick ins Buch - Eulenspiegel Verlagsgruppe

[PDF] Blickpunkt Ausgabe 21-2012

[PDF] Blickpunkt Wirtschaft Volksbank

[PDF] blickpunkt • ost - Herz Jesu - Diözese Rottenburg Stuttgart

[PDF] blicos 05. Asociaciones del Sector

[PDF] BLIGH ISLAND MARINE PROVINCIAL PARK

[PDF] BLIKI Serge Alphonse - Anciens Et Réunions

[PDF] Blin Michel - Centre d`histoire du travail, Nantes

[PDF] blind 1 : profils des talents - Anciens Et Réunions