Oncologic impact of lateral lymph node metastasis at the distal lateral compartment in locally advanced low rectal cancer after neoadjuvant (chemo)radiotherapy

Features of Lateral Pelvic Lymph Nodes Associated With Pathological Involvement After Total Neoadjuvant Therapy in Patients Undergoing Lateral Pelvic Lymph Node Dissection

BACKGROUND

There is a lack of consensus regarding treating involved lateral pelvic lymph nodes in rectal cancer.

OBJECTIVE

This study aimed to evaluate the clinical and MRI-based factors associated with pathological lateral pelvic lymph node metastasis in patients undergoing total neoadjuvant therapy and lateral pelvic lymph node dissection.

DESIGN

This is a retrospective study.

SETTINGS

This study was conducted at a single comprehensive cancer center.

PATIENTS

A total of 107 patients with advanced low rectal cancer with pretreatment enlarged lateral pelvic lymph nodes (≥7 mm in long axis) undergoing total neoadjuvant therapy with long-course chemoradiotherapy, followed by total mesorectal excision and lateral pelvic lymph node dissection, were enrolled.

MAIN OUTCOME MEASURES

Pathological lateral pelvic lymph node metastasis and survival.

RESULTS

Among 107 patients, short-axis lateral node diameter at baseline was <7 mm in 48 patients and ≥7 mm in 59 patients. The ≥7 mm group showed significantly higher rates of pathological lateral pelvic lymph node metastasis (44.1% vs 2.1%; p < 0.0001). In this group, pathological lateral pelvic lymph node metastasis was independently associated with pretreatment malignant features and posttreatment short-axis diameter ≥4 mm. Five-year relapse-free survival was significantly lower in patients with posttreatment lateral node diameter ≥4 mm than those with <4 mm (71.1% vs 86.2%, p = 0.0364). Patients with pathological lateral pelvic lymph node metastasis had significantly lower overall survival, relapse-free survival, and local recurrence-free survival rates.

LIMITATIONS

Selection bias exists in a retrospective analysis.

CONCLUSIONS

Pathological lateral pelvic lymph node metastasis is rare in patients with pretreatment short-axis diameter <7 mm. In patients with pretreatment short-axis diameter ≥7 mm, pretreatment malignant features and posttreatment short-axis diameter are both associated with pathological lateral pelvic lymph node metastasis. These factors should be considered when deciding whether to proceed with lateral pelvic lymph node dissection after total neoadjuvant therapy. See Video Abstract.

CARACTERSTICAS DE LOS GANGLIOS LINFTICOS PLVICOS LATERALES ASOCIADOS CON AFECTACIN PATOLGICA DESPUS DE LA TERAPIA NEOADYUVANTE TOTAL EN PACIENTES SOMETIDOS A DISECCIN LATERAL DE GANGLIOS LINFTICOS PLVICOS

ANTECEDENTES:No existe consenso sobre el tratamiento de los ganglios linfáticos pélvicos laterales afectados en el cáncer rectal.OBJETIVO:Este estudio tuvo como objetivo evaluar los factores clínicos y basados en imágenes de resonancia magnética asociados con la metástasis patológica de los ganglios linfáticos pélvicos laterales en pacientes sometidos a terapia neoadyuvante total y disección lateral de ganglios linfáticos pélvicos.DISEO:Este es un estudio retrospectivo.EORNO CLINICO:Este estudio se llevó a cabo en un solo centro oncológico integral.PACIENTES:Se inscribieron 107 pacientes con cáncer rectal bajo avanzado con ganglios linfáticos pélvicos laterales agrandados antes del tratamiento (≥7 mm en el eje largo) sometidos a terapia neoadyuvante total con quimiorradioterapia de larga duración, seguida de escisión mesorrectal total y disección de ganglios linfáticos pélvicos laterales.PRINCIPALES MEDIDAS DE RESULTADOS:Metástasis patológica de ganglios linfáticos pélvicos laterales y supervivencia.RESULTADOS:Entre 107 pacientes, 48 tenían un diámetro ganglionar lateral en el eje corto <7 mm al inicio, mientras que 59 tenían ≥7 mm. El grupo de ≥7 mm mostró tasas significativamente más altas de metástasis patológica de los ganglios linfáticos pélvicos laterales (44,1% vs 2,1%; p < 0,0001). En este grupo, la metástasis patológica de los ganglios linfáticos pélvicos laterales se asoció de forma independiente con características malignas previas al tratamiento y un diámetro ganglionar lateral posterior al tratamiento ≥4 mm. La supervivencia sin recidiva a los cinco años fue significativamente menor en pacientes con un diámetro ganglionar lateral posterior al tratamiento ≥4 mm que en aquellos con un diámetro <4 mm (71,1% vs 86,2%, p = 0,0364). Los pacientes con la metástasis patológica de los ganglios linfáticos pélvicos laterales tuvieron tasas de supervivencia global, supervivencia sin recidiva y supervivencia sin recurrencia local significativamente más bajas.LIMITACIONES:Existe sesgo de selección en un análisis retrospectivo.CONCLUSIONES:La metástasis patológica de los ganglios linfáticos pélvicos laterales es poco frecuente en pacientes con un diámetro del eje corto previo al tratamiento <7 mm. En pacientes con un diámetro del eje corto previo al tratamiento ≥7 mm, las características malignas previas al tratamiento y el diámetro del eje corto posterior al tratamiento se asocian con metástasis patológica de los ganglios linfáticos pélvicos laterales. Estos factores deben tenerse en cuenta al decidir si se debe proceder a la disección de los ganglios linfáticos pélvicos laterales después de la terapia neoadyuvante total. (Traducción- Dr. Francisco M. Abarca-Rendon).

Surgical anatomy of lateral lymph node dissection: landmarks and areas of dissection in minimally invasive surgery

Lateral lymph node dissection (LLND) for rectal cancer is a vital procedure to achieve en bloc removal of metastatic lateral lymph nodes with surrounding fat tissues, guided by precise anatomical landmarks. The anatomy of the lateral compartment, however, is not straightforward for the majority of surgeons. Inadequate knowledge of the vascular and neural anatomy may increase the risk of intraoperative complications such as bleeding, nerve injury and incomplete lymph node dissection. Minimally invasive surgery provides enhanced visualization of the surgical anatomy in the lateral compartment. Comprehensive knowledge of surgical anatomy is indispensable for successful LLND, and  simplifying the anatomy into the planes makes the procedure accessible for surgeons. This article  presents anatomical landmarks essential for standardizing the step-by-step procedures of LLND and review the literature. i.e., for safe implementation of the procedures.

A management of patients achieving clinical complete response after neoadjuvant therapy and perspectives: on locally advanced rectal cancer

Neoadjuvant chemoradiotherapy (nCRT) followed by total mesorectal excision (TME) and selective use of adjuvant chemotherapy is currently considered the standard of care for locally advanced rectal cancer (LARC). Despite this, the concept of organ preservation is gradually challenging this approach. The management of complete clinical remission (cCR) lacks international consensus, leading scholars to develop their own perspectives based on well-designed studies and long-term data from large multicenter cohorts. To ensure appropriate treatment, this review focuses on the choice of neoadjuvant therapy, criteria for defining cCR, and treatment strategies for patients who achieve cCR after neoadjuvant therapy. By providing guidance on the accurate management of LARC patients after cCR, this review aims to prevent over- or under-treatment.

Management of internal iliac and obturator lymph nodes in mid-low rectal cancer

In rectal cancer treatment, the diagnosis and management of lateral pelvic lymph nodes (LLN) are critical for preventing local recurrence. Over time, scholars have reached a consensus: when imaging suggests LLN metastasis, combining neoadjuvant chemoradiotherapy (nCRT) with selective LLN dissection (LLND) can mitigate the risk of recurrence. Selective LLND typically encompasses lymph nodes in the internal iliac and obturator regions. Recent studies emphasize distinctions between internal iliac and obturator lymph nodes regarding prognosis and treatment outcomes, prompting the need for differentiated diagnostic and treatment approaches.

Comparison of laparoscopic lateral lymph node dissection for rectal cancer with and without routine resection of the visceral branches of internal iliac artery

PURPOSE

This study aimed to explore the safety and feasibility of the modified lateral lymph node dissection (LLND) with routine resection of the visceral branches of internal iliac vessels (IIVs) for mid-low-lying rectal cancer.

MATERIALS AND METHOD

Consecutive patients undergoing LLND for rectal cancer were divided into the routine visceral branches of the IIVs resection group (RVR group) and the NRVR group (without routine resection). The main outcomes were postoperative complications and the number of lateral lymph nodes harvested.

RESULTS

From 2012 to 2021, a total of 75 and 57 patients were included in the RVR and NRVR group, respectively. The operative time was reduced in the RVR group (p = 0.020). No significant difference was observed between the two groups for the incidence of total, major, or minor postoperative complications. Pathologically confirmed LLNM were 24 (32%) patients in the RVR group and 12 (21.1%) in the NRVR group (p = 0.162). The number of lateral lymph nodes harvested had no significant difference between two groups (11 vs. 12, p = 0.329).

CONCLUSION

LLND with routine resection of visceral branches of IIVs is safe and feasible, which brings no major complication or long-term urinary disorder.

Standardization of robot-assisted pelvic lymph node dissection-Development of a common understanding of regional anatomy and surgical technique based on cross-disciplinary discussion among colorectal surgery, urology, and gynecology

BACKGROUND

Pelvic lymph node dissection is a procedure performed in gastroenterological surgery, urology, and gynecology. However, due to discrepancies in the understanding of pelvic anatomy among these departments, cross-disciplinary discussions have not been easy. Recently, with the rapid spread of robotic surgery, the importance of visual information in understanding pelvic anatomy has become even more significant. In this project, we attempted to clarify a shared understanding of pelvic anatomy through cross-disciplinary discussions.

METHOD

From May 2020 to November 2021, a total of 11 discussions were held entirely online with 5 colorectal surgery specialists, 4 urologists, and 4 gynecologists. The discussions focused on evidence from each specialty and surgical videos, aiming to create a universally understandable pelvic anatomical illustration.

RESULTS

The common area of dissection recognized across the three departments was identified as the obturator lymph nodes. A dynamic illustration of pelvic anatomy was created. In addition to a bird's-eye view of the pelvis, a pelvic half view was developed to enhance understanding of the deeper pelvic anatomy. The following insights were incorporated into the illustration: (1) the cardinal ligament in gynecology partly overlaps with the vesicohypogastric fascia in colorectal surgery; (2) the obturator lymph nodes continue cephalad into the fossa of Marcille in urology; and (3) the deep uterine vein in gynecology corresponds to the inferior vesical vein in colorectal surgery.

CONCLUSION

Based on the dynamic illustration of pelvic anatomy from cross-disciplinary discussions, we anticipate advancements in pelvic lymph node dissection aiming for curative and safe outcomes.

Adding Induction Chemotherapy Before Chemoradiotherapy with Total Mesorectal Excision and Selective Lateral Lymph Node Dissection for Patients with Poor-Risk, Locally Advanced, Mid-to-Low Rectal Cancer May Improve Oncologic Outcomes: A Propensity Score-Matched Analysis

BACKGROUND

This study aimed to investigate whether the addition of induction chemotherapy before chemoradiotherapy (CRT) and total mesorectal excision (TME) with selective lateral lymph node dissection improves disease-free survival for patients with poor-risk, mid-to-low rectal cancer.

METHODS

The authors' institutional prospective database was queried for consecutive patients with clinical stage II or III, primary, poor-risk, mid-to-low rectal cancer who received neoadjuvant treatment followed by TME from 2004 to 2019. The outcomes for the patients who received induction chemotherapy before neoadjuvant CRT (induction-CRT group) were compared (via log-rank tests) with those for a propensity score-matched cohort of patients who received neoadjuvant CRT without induction chemotherapy (CRT group).

RESULTS

From 715 eligible patients, the study selected two matched cohorts with 130 patients each. The median follow-up duration was 5.4 years for the CRT group and 4.1 years for the induction-CRT group. The induction-CRT group had significantly higher rates of 3-year disease-free survival (83.5 % vs 71.4 %; p = 0.015), distant metastasis-free survival (84.3 % vs 75.2 %; p = 0.049), and local recurrence-free survival (98.4 % vs 94.4 %; p = 0.048) than the CRT group. The pathologically complete response rate also was higher in the induction-CRT group than in the CRT group (26.2 % vs 10.0 %; p < 0.001). Postoperative major complications (Clavien-Dindo classification ≥III) did not differ significantly between the two groups (12.3 % vs 10.8 %; p = 0.698).

CONCLUSIONS

The addition of induction chemotherapy to neoadjuvant CRT appeared to improve oncologic outcomes significantly, including disease-free survival, for the patients with poor-risk, mid-to-low rectal cancer who underwent TME using selective lateral lymph node dissection.

Geriatric nutritional risk index after neoadjuvant chemoradiotherapy and survival in older patients with advanced rectal cancer

PURPOSE

To investigate the clinical impact of malnutrition on the survival of older patients with advanced rectal cancer who underwent neoadjuvant chemoradiotherapy.

METHODS

We investigated the clinical significance of the geriatric nutritional risk index (GNRI) in 237 patients aged over 60 years with clinical stage II/III rectal adenocarcinoma who were treated with neoadjuvant long-course chemoradiotherapy or total neoadjuvant therapy followed by radical resection from 2004 to 2017. Pre-treatment and post-treatment GNRI were evaluated, with patients split into low (< 98) and high (≥ 98) GNRI groups. The prognostic impact of pre-treatment and post-treatment GNRI levels on overall survival (OS), post-recurrence survival (PRS), and disease-free survival (DFS) was evaluated using univariate and multivariate analyses.

RESULTS

Fifty-seven patients (24.1%) before neoadjuvant treatment and 94 patients (39.7%) after neoadjuvant treatment were categorized with low GNRI. Pre-treatment GNRI levels were not associated with OS (p = 0.80) or DFS (p = 0.70). Patients in the post-treatment low GNRI group had significantly poorer OS than those in the post-treatment high GNRI group (p = 0.0005). The multivariate analysis showed that post-treatment low GNRI levels were independently associated with poorer OS (hazard ratio, 3.06; 95% confidence interval, 1.55-6.05; p = 0.001). Although post-treatment GNRI levels were not associated with DFS (p = 0.24), among the 50 patients with recurrence, post-treatment low GNRI levels were associated with poorer PRS (p = 0.02).

CONCLUSION

Post-treatment GNRI is a promising nutritional score associated with OS and PRS in patients over 60 years with advanced rectal cancer treated with neoadjuvant chemoradiotherapy.

Current status of transanal total mesorectal excision for rectal cancer and the expanding indications of the transanal approach for extended pelvic surgeries

Transanal total mesorectal excision (taTME) has been rapidly accepted as a promising surgical approach to the distal rectum. The benefits include ease of access to the bottom of the deep pelvis linearly over a short distance in order to easily visualize the important anatomy. Furthermore, the distal resection margins can be secured under direct vision. Additionally, a two-team approach combining taTME with a transabdominal approach could decrease the operative time and conversion rate. Although taTME was expected to become more rapidly popularized worldwide, enthusiasm for it has stalled due to unfamiliar intraoperative complications, a lack of oncologic evidence from randomized trials, and the widespread use of robotic surgery. While international registries have reported favorable short- and medium-term outcomes from taTME, a Norwegian national study reported a high local recurrence rate of 9.5%. The characteristics of the recurrences included rapid, multifocal growth in the pelvis, which was quite different from recurrences following traditional transabdominal TME; thus, the Norwegian Colorectal Cancer Group reached a consensus for a temporary moratorium on the performance of taTME. To ensure acceptable baseline quality and patient safety, taTME should be performed by well-trained colorectal surgeons. Although the appropriate indications for taTME remain controversial, the transanal approach is extremely important as a means of goal setting in difficult TME cases and as an aid to the transabdominal approach in various types of extended pelvic surgeries. The benefits in transanal lateral lymph node dissection and pelvic exenteration are presented herein.