Pathological evaluation of mesocolic resection quality and ex vivo methylene blue injection: what is the impact on lymph node harvest after colon resection for cancer?

The impact of methylene blue in colon cancer: a retrospective multicentric study

INTRODUCTION

Discussions about the optimal lymph node (LN) count and its therapeutic consequences have persisted over time. The final LN count in colorectal tissues is affected by a variety of variables (patient, tumor, operation, pathologist, immune response). Methylene blue (MB) intra-arterial injection is a simple and inexpensive procedure that can be used to enhance lymph node count.

AIM

Analyze whether there is a statistically significant difference between intra-arterial methylene blue injection and conventional dissection for the quantification of lymph nodes and determine if there is a variation in the quality of lymph node acquisition.

METHODS AND RESULTS

Between 2015 and 2022, we conducted a retrospective analysis of colon cancer specimens. Data on the tumor's features, the number of lymph nodes, the number of lymph nodes that were positive, and other factors had been collected. The number of identified lymph nodes was highly significantly improved in the study group (P < 0.05). There is not a significant statistical difference between groups regarding the metastatic lymph node harvest. The group with injection of intra-arterial methylene blue shows a significantly decreased (P < 0.05) of the of cases with less than 12 lymph nodes recovered comparing with the control group.

CONCLUSION

Colon cancer specimens can be easily evaluated concerning lymph nodes using the methylene blue method. Therefore, we strongly advise this approach as a standard procedure in the histological evaluation of colon cancer specimens in order to maximize the identification of lymph nodes. However, the detection of metastatic lymph nodes was unaffected significantly.

The impact of methylene blue in colorectal cancer: Systematic review and meta-analysis study

PURPOSE

In patients with colorectal cancer (CRC), the most important factor to decide the need of adjuvant chemotherapy is the histological lymph node (LN) evaluation. Our work aimed to give a broad view over the use of methylene blue and its consequences in the number of lymph node harvest.

METHODS

PUBMED, WEB OF SCIENCE and EMBASE databases were consulted, retrieving clinical trials, which mentioned the used of intra-arterial methylene blue in patients with colorectal cancer.

RESULTS

Eighteen clinical trials analyzing the use of intra-arterial methylene blue in specimens of colorectal cancer were selected. The articles show a statistical difference between the use of methylene blue and the classical dissection in both variable at study. The results of the statistical analysis of the lymph node harvest variable demonstrate a significant statistical difference between the group that received methylene blue injection and the group that underwent conventional dissection. There is a significant statistical difference between the experimental and control groups for the ideal lymph node harvest (lymph node harvest count greater than 12).

CONCLUSION

The use of intra-arterial methylene blue revealed a high potential for the quantification of lymph nodes, considering the increase of lymph node harvest and the higher percentage of cases with more than 12 lymph nodes count, albeit the high heterogeneity between the studies in terms of reported results. Future investigations with controlled double blinded studies obtaining better categorized results should be conducted in order to better evaluate this technique and compare it to the current paradigm.

Standard Lymphadenectomy for Esophageal and Lung Cancer: Variability in the Number of Examined Lymph Nodes Among Pathologists and Its Survival Implication

AIM

We compared variability in number of examined lymph nodes between pathologists and analyzed survival implications in lung and esophageal cancer after standardized lymphadenectomy.

METHODS

Outcomes of 294 N2 dissected lung cancer patients and 132 2-field dissected esophageal cancer patients were retrospectively examined. The primary outcome was difference in reported lymph node count among pathologists. Secondary outcomes were overall and disease-specific survival related to this count and survival related to the 50% probability cut-off value of detecting metastasis based on the number of examined lymph nodes.

RESULTS

The median number of examined lymph nodes in lung cancer was 13 (IQR 9-17) and in esophageal cancer it was 22 (18-29). The pathologist with the highest median number of examined nodes had > 50% higher lymph node yield compared with the pathologist with the lowest median number of nodes in lung (15 vs. 9.5, p = 0.003), and esophageal cancer (28 vs. 17, p = 0.003). Survival in patients stratified by median reported lymph node count in both lung (adjusted RMST ratio < 14 vs. ≥ 14 lymph nodes 0.99, 95% CI 0.88-1.10; p = 0.810) and esophageal cancer (adjusted RMST ratio < 25 vs. ≥ 25 lymph nodes 0.95, 95% CI 0.79-1.15, p = 0.612) was similar. The cut-off value for 50% probability of detecting metastasis by number of examined lymph nodes in lung cancer was 15.7 and in esophageal cancer 21.8. When stratified by this cut-off, no survival differences were seen.

CONCLUSION

The quality of lymphadenectomy based on lymph node yield is susceptible to error due to detected variability between pathologists in the number of examined lymph nodes. This variability in yield did not have any survival effect after standardized lymphadenectomy.

Advanced Lymph Node Staging With Ex Vivo Intra-arterial Indigo Carmine Injection After Transanal Total Mesorectal Excision for Rectal Cancer: A Retrospective Cohort Study

BACKGROUND

Exact lymph node staging is essential in rectal cancer therapy.

OBJECTIVE

The aim of the study was to assess the impact of intra-arterial indigo carmine injection after transanal total mesorectal excision on the number of retrieved lymph nodes.

DESIGN

This was a retrospective, nonrandomized study.

SETTINGS

The study was conducted at a tertiary hospital by a multidisciplinary team.

PATIENTS

Patients who underwent transanal total mesorectal excision for suspected rectal cancer between 2013 and 2019 were included.

INTERVENTIONS

Rectal cancer specimens received ex vivo intra-arterial indigo carmine injection to stain lymph nodes.

MAIN OUTCOME MEASURES

Outcome measures included the number of retrieved lymph nodes with or without staining.

RESULTS

Specimens of 189 patients were analyzed, of which 108 (57.1%) were stained with indigo carmine. A mean of 19.8 ± 6.1 lymph nodes was identified in stained samples compared to 16.0 ± 4.9 without staining ( p < 0.001). Multivariable analysis showed that 3.2 additional lymph nodes were found in stained specimens (95% CI: 1.0 to 5.3; p = 0.02). In stained specimens the adequate lymph node count (≥12) was increased in univariable (odds ratio: 3.24, 95% CI: 1.13 to 10.65; p = 0.03) but not in multivariable analysis. Indigo carmine injection had no effect on the number of positive lymph nodes or the nodal stage. Chemoradiotherapy reduced the lymph node count by 2.5 ( p = 0.008). After staining, 95.0% of patients with chemoradiotherapy had ≥12 lymph nodes retrieved. The median follow-up of patients was 24.2 months with a local recurrence rate of 3.3%.

LIMITATIONS

The study is limited by its retrospective design and the nonrandomized allocation.

CONCLUSIONS

Ex vivo intra-arterial indigo carmine injection increases the number of isolated lymph nodes after transanal total mesorectal excision regardless of neoadjuvant chemoradiotherapy. Indigo carmine injection is not associated with nodal upstaging or an increased number of tumor-positive lymph nodes. See Video Abstract at http://links.lww.com/DCR/B839 .

ESTADIFICACIN AVANZADA DE LOS GANGLIOS LINFTICOS CON INYECCIN INTRAARTERIAL EX VIVO,DE NDIGO CARMN,DESPUS DE LA ESCISIN TOTAL DEL MESORRECTO POR VA TRANSANAL PARA CNCER DE RECTO UN ESTUDIO DE COHORTE RETROSPECTIVO

ANTECEDENTES:La estadificación exacta de los ganglios linfáticos es esencial en la tratamiento del cáncer de recto.OBJETIVO:El objetivo del estudio fue evaluar el impacto de la inyección intraarterial de índigo carmín después de la escisión total del mesorrecto por vía transanal con relación al número de ganglios linfáticos recuperados en el espécimen quirúrgico..DISEÑO:Estudio retrospectivo no aleatorizado.AJUSTE:El estudio se llevó a cabo en un hospital de tercer nivel por un equipo multidisciplinario.PACIENTES:Pacientes a quienes se les practicó escisión total del mesorrecto por vía transanal por sospecha de cáncer de recto entre 2013 y 2019.INTERVENCIONES:Al espécimen quirúrgico que se obtuvo, se le practicó inyección intraarterial ex vivo, de índigo carmín para teñir los ganglios linfáticos.PRINCIPALES MEDIDAS DE RESULTADO:El número de ganglios linfáticos recuperados con o sin tinción.RESULTADOS:Se analizaron muestras de 189 pacientes, de los cuales 108 (57,1%) fueron teñidos con índigo carmín. Se identificó una media de 19,8 ± 6,1 ganglios linfáticos en las muestras teñidas en comparación con 16,0 ± 4,9 sin tinción ( p < 0,001). El análisis multivariado mostró que se encontraron 3.2 ganglios linfáticos adicionales en las muestras teñidas (intervalo de confianza del 95%: 1,0 a 5,3; p = 0,02). En las muestras teñidas, el recuento adecuado de ganglios linfáticos (≥12) aumentó en el análisis univariado (razón de posibilidades: 3,24, intervalo de confianza del 95%: 1,13 a 10,65; p = 0,03) pero no en el multivariado. La inyección de índigo carmín no tuvo ningún efecto sobre el número de ganglios linfáticos positivos o el estadio ganglionar. La quimiorradioterapia redujo el recuento de ganglios linfáticos en 2,5 ( p = 0,008). Después de la tinción, en el 95,0% de los pacientes con quimiorradioterapia se recuperaron ≥12 ganglios linfáticos. La mediana de seguimiento de los pacientes fue de 24,2 meses con una tasa de recurrencia local del 3,3%.LIMITACIONES:El estudio está limitado por su diseño retrospectivo y la asignación no aleatoria.CONCLUSIONES:La inyección ex vivo de índigo carmín intraarterial aumenta el número de ganglios linfáticos aislados después de la escisión total del mesorrectal por vía transanal a pesar de la quimiorradioterapia neoadyuvante. La inyección de índigo carmín no se asocia con un aumento del estadio de los ganglios ni con un mayor número de ganglios linfáticos positivos para tumor. Consulte Video Resumen en http://links.lww.com/DCR/B839 . (Traducción-Eduardo Londoño-Schimmer ).

Role of methylene blue in detecting the sentinel lymph node in colorectal cancer: In vivo vs. ex vivo technique

The identification of sentinel lymph nodes is a valuable oncological method, which aims at mapping lymphatic drainage and has the advantage of correctly staging the disease and assessing prognosis. Lymph node invasion is an important prognostic feature. In colorectal cancer, lymphadenectomy is not influenced by the positive or negative status of the sentinel lymph node. The identification of lymph nodes with possible invasion by staining the primary tumor with methylene blue can lead to improved staging and management. In other words, the consequent administration of neoadjuvant therapy (chemotherapy) to the appropriate patients may result in lower recurrence rates. Thus, the aim of the present study was to use methylene blue to identify the sentinel node/nodes in colorectal cancer and to determine whether the dye-capturing nodes were invaded by the tumor. This is a non-randomized prospective study, in which 26 patients with colon cancer with surgical indication were enrolled. Two types of methods were utilized: in vivo (16 patients) and ex vivo (10 patients). The identification rate was 75% for the in vivo technique and 60% for the ex vivo technique, resulting in a 69.26% overall identification rate. Of 18 patients with sentinel lymph nodes identified using dye, routine histological examination detected metastases in 6 (33.33%) of these patients. In conclusion, further research should be conducted into how the clinical application of sentinel node detection can be employed in colorectal cancer.

Clinicopathological Factors Affecting Lymph Node Yield and Positivity in Left-Sided Colon and Rectal Cancers

Background

Colorectal cancer (CRC) is a significant cause of cancer‐related deaths worldwide and is the third most common cause of cancer deaths in the UK. The status of lymph node metastasis is a key factor for predicting the prognosis of a patient's CRC.

Aims

This study aimed to analyze the demographics of left-sided colonic and rectal cancers at a single institution. We looked closely at the correlation between patient age and various histological factors. We tried to find any significant difference in lymph node yield (LNY) between laparoscopic surgery (LS) and open surgery (OS). We aimed to identify any statistical correlation between LNY and lymph node positivity (LNP) with other patient, surgical and histopathological features.

Methodology

This is a retrospective, non-interventional review of consecutive patients who underwent left-sided colonic and rectal cancer resections over a three-year period between 01 April 2018 and 31 March 2021. Descriptive and inferential statistical analyses were used. Chi-squared / Fisher exact test was used on a categorical scale between two or more groups and non-parametric setting for qualitative data analysis.

Results

A total of 102 patients were included in the study. No statistical correlation was found between the age of the patient with the LNY, LNP, location of the tumor, type, and urgency of the operation. LNY ranged between one and 43 nodes (median (interquartile range (IQR)) 17, 8). There was no statistically significant difference in LNY between laparoscopic surgery (LS) and open surgery (OS) (p=0.1449). Significant statistical correlation was identified between LNP and completeness of resection (CoR) (p=0.039), vascular invasion (VI) (p<0.001), perineural invasion (PI) (p<0.001), and circumferential resectional margin involvement (CRMI) (p=0.039).

Discussion

LNY and LNP are important prognostic indices in colorectal cancer. Patient age, tumor location, the urgency of surgery, and consultant experience did not significantly impact the LNY. Our study showed a positive correlation between LNP and CRMI, VI and PI comparable to literature. Contrary to other studies, we found no statistical significance between LS vs. OS and LNY. Whether 12 nodes per patient is an appropriate level remains controversial.

A Proposal for Novel Standards of Histopathology Reporting for D3 Lymphadenectomy in Right Colon Cancer: The Mesocolic Sail and Superior Right Colic Vein Landmarks

BACKGROUND

Strong agreement exists concerning the standards of pathologic reporting for total mesorectal excision and complete mesocolic excision. It represents a quality standard that correlates with survival. However, no agreed standards of reporting are available to define D3 lymphadenectomy for right colectomy.

OBJECTIVE

The purpose of this study was to define anatomopathological standards of specimen quality obtained from the surgical specimen when an oncologic right hemicolectomy with D3 lymphadenectomy has been correctly performed.

DESIGN

This study was conducted in 2 different phases. The first part consisted of a cadaver-based study of right colon anatomy, and the second part consisted of a prospective assessment of a series of surgical specimens obtained after right hemicolectomy for cancer.

SETTINGS

The anatomic phase of the study was performed in collaboration with the University of Valencia Department of Anatomy and Embryology. The second part was performed at a colorectal unit of a tertiary hospital.

PATIENTS

Seventeen cadavers were used for the first phase, and 65 surgical specimens were examined for the second part of the study.

MAIN OUTCOME MEASURES

In each specimen, the pathologists looked for anatomic structures defined as markers of quality standards of the D3 lymphadenectomy during the first phase. Specimens were classified as complete, partial, and incomplete D3 lymphadenectomy.

RESULTS

Twenty percent of specimens were classified as incomplete D3 lymphadenectomy, 31% as partial, and 49% as complete. A median number of 14 (6-64), 22 (11-47), and 29 (14-55) lymph nodes were isolated (p = 0.01). Similarly, the median numbers of lymph nodes isolated in the area of D3 lymphadenectomy were 0 in incomplete, 1 (0-5) in Partial, and 3 (0-8) in Complete D3 lymphadenectomy specimens (p = 0.0001).

LIMITATIONS

A large multicenter study with adequate power is needed.

CONCLUSIONS

We propose the right mesocolic sail and trunk of superior right colic vein as new and reproducible anatomopathologic standards of D3 lymphadenectomy in oncologic right hemicolectomy. See Video Abstract at http://links.lww.com/DCR/B149. PROPUESTA PARA NUEVOS ESTÁNDARES HISTOPATOLÓGICOS EN LA LINFADENECTOMÍA D3 EN EL CÁNCER DE COLON DERECHO: LA VELA MESOCÓLICA Y LA VENA CÓLICA DERECHA SUPERIOR: Existe un claro acuerdo sobre los estándares de calidad patológicos para la escisión total del mesorrecto y la escisión completa del mesocolon. Son considerados "estándar de calidad" que se correlaciona con la supervivencia. Sin embargo, no se dispone de estándares de calidad para definir la linfadenectomía D3, en la colectomía derecha.Definir los estándares anatomopatológicos de calidad obtenidos de una muestra quirúrgica, cuando se ha realizado correctamente una hemicolectomía derecha oncológica, con linfadenectomía D3.Dos fases diferentes. La primera parte consistió en un estudio basado en la anatomía del colon derecho, realizado en cadáveres, y la segunda parte consistió en una evaluación prospectiva de una serie de muestras quirúrgicas obtenidas después de la hemicolectomía derecha para cáncer.La fase anatómica del estudio se realizó en colaboración con el Departamento de Anatomía y Embriología de la Universidad de Valencia. La segunda parte se realizó en la Unidad Colorrectal de un hospital terciario.Se utilizaron diecisiete cadáveres para la primera fase y se examinaron 65 muestras quirúrgicas para la segunda parte del estudio.En cada muestra, los patólogos buscaron estructuras anatómicas definidas, como marcadores de los estándares de calidad de la linfadenectomía D3, durante la primera fase. Las muestras se clasificaron como linfadenectomía D3 completa, parcial e incompleta.El veinte por ciento de las muestras se clasificaron como "Linfadenectomía D3 Incompleta", el 31% como "Parcial" y el 49% como "Completa." Se aisló una media de 14 (6-64), 22 (11-47) y 29 (14-55) ganglios linfáticos respectivamente (p = 0,01). Del mismo modo, el número medio de ganglios linfáticos aislados en el área de la linfadenectomía D3 fue 0 en "Incompleta", 1 (0-5) en "Parcial" y 3 (0-8) en muestras de "Linfadenectomía D3 Completa" (p = 0,0001).Se necesita un estudio multicéntrico con potencia adecuada.Proponemos la vela mesocólica derecha y el tronco de la vena cólica derecha superior, como estándares anatomopatológicos nuevos y reproducibles de linfadenectomía D3, en hemicolectomía derecha oncológica. Consulte Video Resumen en http://links.lww.com/DCR/B149.

Impact of perioperative transfusions and sepsis on long-term oncologic outcomes after curative colon cancer resection. A retrospective analysis of a prospective database

OBJECTIVE

Intra-abdominal septic complications (IASC) affect short-term outcomes after surgery for colon cancer. Blood transfusions have been associated with worse short-term results. The role of IASC and blood transfusions on long-term oncologic results is still debated. This study aims to assess the impact of these two variables on survival after curative colon cancer resection.

PATIENTS AND METHODS

Retrospective analysis of a prospectively maintained database of patients who underwent curative surgery for colon cancer at a university hospital, between 1993 and 2010. Cox regression was used to identify the role of IASC and transfusions (alone and combined) on local recurrence (LR), disease-free survival (DFS), and cancer-specific survival (CSS).

RESULTS

Out of the 1686 patients analyzed, 1277 fit in the inclusion criteria. Colorectal surgeons performed the procedure in 82.2% of the patients. Blood transfusions were administered to 25.8% of the patients. Thirty-day complication and mortality rates were 34.5% and 6.1%. IASC occurred in 9.9%. The mean follow-up was 66 months. The 5-year rates of LR, DFS, and CSS were 7%, 79.8%, and 85.1%. The year of surgery and pT (Hazard ratio 9.35, 95% CI 1.23-70.9, for T4) and pN (Hazard ratio 2.57, 95% CI 1.39-4.72, for N2) stages were independent risk factors for LR. The same variables, bowel obstruction and surgeries performed by surgeons not specialized in colorectal surgery, were also associated with worse DFS and CSS. IASC and blood transfusions were not associated with LR, DFS, and CSS, whether alone or combined.

CONCLUSIONS

IASC and transfusions were not associated with worse oncological outcomes after curative colon cancer surgery per se. Other factors were more important predictors of survival.

The fusion fascia of Fredet: an important embryological landmark for complete mesocolic excision and D3-lymphadenectomy in right colon cancer

BACKGROUND

The fusion fascia of Toldt is a well-known landmark used by colorectal surgeons. On the contrary, the fusion fascia of Fredet (the plane between the ascending mesocolon and the visceral duodenal-pancreatic peritoneum) still remains a neglected embryological structure. Aim of this study was to provide an anatomic description of this fascia and its application to minimally invasive D3-lymphadenectomy (D3-L) and complete mesocolic excision (CME) for right colon cancer.

METHODS

First phase: Cadaveric dissection and anatomic description of the fascia of Fredet. Second phase: prospective evaluation of its surgical application in a consecutive series of laparoscopic right hemicolectomies with CME and D3-L at a tertiary hospital.

RESULTS

The fascia of Fredet was identified and dissected in one fresh and two formalin-fixed cadavers. The trunk of Henle and the medial border of the superior mesenteric vein defined the medial limit of this embryologic plane. Seventeen patients were operated on. Laparoscopic dissection of the fascia of Fredet was possible in every patient. Median operative time was 210 (120-380) min. There were no major postoperative complications. All cases were adenocarcinomas, except one adenomatous polyp. T stage was Tis in three, T2 in two, T3 in seven, and T4 in five patients. Median number of harvested lymph nodes was 24 (9-39). Lymphatic invasion was found in six patients. All resections were classified as satisfactory mesocolic excision and R0. Median postoperative length of stay was 6 (4-20) days. Median follow-up time was 28 (16-41) months. Local and distal recurrence rate was 0.

CONCLUSION

The fusion fascia of Fredet is useful to achieve CME and D3-L in right colon cancers with reduced risk of intraoperative complications. This structure is particularly suitable for minimally invasive surgery; therefore, we encourage awareness of the fascia of Fredet by colorectal surgeons.

The prognostic significance of lymph node size in node-positive colon cancer

OBJECTIVES

To (i) show the outcome benefits of enlarged lymph nodes in node-positive colon cancer cases, as it was shown previously in negative node cases; (ii) disprove the stage migration theory and (iii) list the factors affecting lymph node size and yield.

METHODS

A retrospective study including 234 node-positive colon cancer cases was scheduled and performed. All recovered lymph nodes (6969) from 234 cases were microscopically examined in regard to (a) lymph node size (b) presence of metastasis (c) extent of intra-nodal metastasis. On the basis of resulting data, a statistical analysis was performed.

RESULTS

Metastases occurred in all size categories, though more often in larger lymph nodes. Fifty-one percent of all metastasised nodes were 2 to 6 mm in size. Approximately half of all nodes >10 mm were microscopically free of cancer. Cases with a small lymph node metastasis to lymph node size ratio (MSR) had a better prognosis than others: 85 months (95% CI: 72-97) vs. 67 months (95% CI: 47-88), p <0.001 (mean, overall survival). To differentiate between cases with the same ratio but different absolute lymph nodes sizes, we divided the cases into two groups that differed in their number of moderate to large lymph nodes. The group with more moderate to large lymph nodes showed a clear outcome benefit: 104 months (95% CI: 86-122) vs. 66 months (95% CI: 54-77), p = 0.014 (mean, overall survival).

CONCLUSIONS

Metastasised lymph nodes affect all size categories, and large lymph nodes are not always metastasised. The combination of enlarged lymph nodes and a small lymph node metastasis to lymph node size ratio (MSR) is associated with a better prognosis than others. When enlarged lymph nodes were considered as surrogate markers of an effective local immune response due to nodal hyperplasia, the immune system could be seen as the confounder affecting both lymph node size and prognosis. Our results are pointing in this direction and, along with other reasons, are challenging the stage migration theory.

Stage migration vs immunology: The lymph node count story in colon cancer

Lymph node staging is of crucial importance for the therapy stratification and prognosis estimation in colon cancer. Beside the detection of metastases, the number of harvested lymph nodes itself has prognostic relevance in stage II/III cancers. A stage migration effect caused by missed lymph node metastases has been postulated as most likely explanation for that. In order to avoid false negative node staging reporting of at least 12 lymph nodes is recommended. However, this threshold is met only in a minority of cases in daily practice. Due to quality initiatives the situation has improved in the past. This, however, had no influence on staging in several studies. While the numbers of evaluated lymph nodes increased continuously during the last decades the rate of node positive cases remained relatively constant. This fact together with other indications raised doubts that understaging is indeed the correct explanation for the prognostic impact of lymph node harvest. Several authors assume that immune response could play a major role in this context influencing both the lymph node detectability and the tumor’s behavior. Further studies addressing this issue are need. Based on the findings the recommendations concerning minimal lymph node numbers and adjuvant chemotherapy should be reconsidered.

A Comparative Study of Single-Port Laparoscopic Surgery Versus Robotic-Assisted Laparoscopic Surgery for Rectal Cancer

INTRODUCTION

Conventional laparoscopic surgery is the treatment of choice for many abdominal procedures. To further reduce surgical trauma, new minimal invasive procedures such as single-port laparoscopic surgery (SPLS) and robotic assisted laparoscopic surgery (RALS) have emerged. The aim of this study was to compare the early results of SPLS versus RALS in the treatment of rectal cancer.

METHODS

We performed a retrospective analysis of prospectively collected data on patients who had undergone SPLS (n = 36) or RALS (n = 56) in the period between 2010 and 2012. Operative and short-term oncological outcomes were compared.

RESULTS

The RALS group had fewer patients with low rectal cancer and more patients with mid-rectal tumors (P = .017) and also a higher rate of intraoperative complications (14.3% vs 0%, P = .021). The rate of postoperative complications did not differ (P = .62). There were no differences in circumferential resection margins, distal resection margins, or completeness of the mesorectal fascia. The RALS group had a larger number of median harvested lymph nodes (27 vs 13, P = .001). The SPLS group had fewer late complications (P = .025). There were no locoregional recurrences in either of the groups. There was no difference in median follow-up time between groups (P = .58).

CONCLUSION

Both SPLS and RALS may have a role in rectal surgery. The short-term oncological outcomes were similar, although RALS harvested more lymph nodes than the SPLS procedure. However, SPLS seems to be safer with regard to intraoperative and late postoperative complications.

Ex vivo intra-arterial methylene blue injection in the operation theater may improve the detection of lymph node metastases in colorectal cancer

INTRODUCTION

Lymph node (LN) assessment after colorectal cancer resection is fundamentally important for therapeutic and prognostic reasons. LN positivity is an indication for adjuvant treatment. This study aimed to investigate whether immediate postoperative intra-arterial methylene blue (MB) injection (MBI) into colorectal cancer specimens by a surgeon in the operating room could improve the rate of total LN and metastatic LN recovery for pathological examination.

MATERIALS AND METHODS

Seventy-three consecutive patients prospectively enrolled between January 2011 and December 2013 were assigned to the methylene blue (MB)-stained group and compared with 107 controls in the unstained group.

RESULTS

The median number and range values of metastatic LNs, the number of LNs <0.5 cm, the total number of LNs harvested, and the number of cases with LN metastasis were significantly different between the MB-stained and MB-unstained groups (p = 0.016, p = 0.010, p = 0.025, and p = 0.006 respectively).

CONCLUSIONS

Immediate MBI (fresh, unfixed samples) by a surgeon in the operating room may result in a significant increase in the number of metastatic LNs diagnosed and the number of cases with positive LNs. Shifting of the injection from the pathology laboratory to the operation theater would be a good alternative whenever the operation theater is not the area located as the pathology department.

The total number of lymph nodes in resected colon cancer specimens is affected by several factors but the lymph node ratio is independent of these

The number of lymph nodes retrieved from the specimen may be a surrogate measure of the adequacy of extensive colon cancer surgery, but many variables may influence the total lymph node yield of any specimen. We examined which variables would be influential both for negative and positive node sampling.The combined results from 428 patients from three hospitals A to C treated in 2007-2009 with single colon cancers having R0 segmental resections were analysed. The surgical technique and pathology staining methods were slightly different between the hospitals.The mean number of lymph nodes was 15.8 (range 1-60). Twelve or more lymph nodes were harvested in 78% of the specimens. In the multivariate Poisson regression analysis of all TNM stages, the factors associated with the total lymph node harvest were age, pathology handling, tumour location and size (p < 0.001), whereas for TNM stage III alone the pathology handling (p < 0.001) and a radical operating technique (p = 0.003) were highly significant. The total number of lymph nodes was the only significant factor for the number of positive lymph nodes (Posln) according to the multivariate negative regression analysis (p = 0.02) but the analysis of the lymph node ratio (LNR) detected no statistically significant variable.Several factors, and especially the specimen processing technique, were important for the total number of harvested lymph nodes. The number of Posln varied between segments and increased with the total number of harvested lymph nodes, but for LNR no variable was important. LNR seemed to abolish the combined effect of tumour location and the total lymph node yield in prognosis assessment.

Methylene blue-assisted lymph node dissection technique is not associated with an increased detection of lymph node metastases in colorectal cancer

Lymph node staging is of paramount importance for prognosis estimation and therapy stratification in colorectal cancer. A high number of harvested lymph nodes is associated with an improved outcome. Methylene blue-assisted lymph node dissection effectively improves the lymph node harvest and ensures sufficient staging. Now, the effect on node positivity rate and stage-related outcome was investigated. The study cohort with advanced lymph node dissection consisted of 669 colorectal cancer cases of all stages, which were collected between 2007 and 2012. A historical collection of 663 cases investigated with conventional techniques between 2002 and 2004 served as control. Lymph node harvest was dramatically improved in the study group with mean lymph node numbers of 34 ± 17 vs 13 ± 5 (P<0.001) and sufficient staging rates of 98% vs 62% (P<0.001). However, neither the rate of nodal positive cases (37% vs 37%; P = 0.98) nor the rate of N2 cases differed between the two groups (14% vs 13%; P = 0.80). Furthermore, no differences were found concerning the outcome in both groups. The advanced lymph node dissection technique guarantees adequate histopathological lymph node staging in virtually all cases of colorectal cancer and is therefore extremely helpful. The hypothesis that it also provides a higher sensitivity in detecting metastases, however, could be not proved.

Qualitative and quantitative issues of lymph nodes as prognostic factor in colon cancer

For patients undergoing curative resections for colon cancer, the nodal status represents the strongest prognostic factor, yet at the same time the most disputed issue as well. Consequently, the qualitative and quantitative aspects of lymph node evaluation are thus being scrutinized beyond the blunt distinction between 'node positive' (pN+) and 'node negative' (pN0) disease. Controversy ranges from a minimal or 'least-unit' strategy as exemplified by the 'sentinel node' to a maximally invasive or 'all inclusive' approach by extensive surgery. Ranging between these two extremes of node sampling strategies are factors of quantitative and qualitative value, which may be subject to modification. Qualitative issues may include aspects of lymph node harvest reflected by surgeon, pathologist and even hospital performance, which all may be subject to modification. However, patient's age, gender and genotype may be non-modifiable, yet influence node sample. Quantitative issues may reflect the balance between absolute numbers and models investigating the relationships of positive to negative nodes (lymph node ratio; log odds of positive lymph nodes). This review provides an updated overview of the current controversies and a state-of-the-art perspective on the qualitative and quantitative aspects of using lymph nodes as a prognostic marker in colon cancer.