EP165 - Lateral Pelvic Node Resection in Low Rectal Cancer : Imaging Sensitivity and Long-term Oncologic Outcomes

Saturday, May 10, 2025

3:31 PM – 3:36 PM PT

Location: Monitor 9, Sails Pavilion, Upper Level

ePoster Presenter(s)

Rodrigo de Almeida Leite, MD, MSc (he/him/his)

Research Fellow, Colon & Rectal Surgery Department
Massachusetts General Hospital
Boston, Massachusetts, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.

Author(s)

LC

Luiz Eduardo Calil de Assumpção, n/a

Medical Student
Hospital Israelita Albert Einstein
Sao Paulo, Sao Paulo, Brazil

Disclosure information not submitted.
FT

Francisco Tustumi, MD, PHD

Surgeon
Hospital Israelita Albert Einstein
Sao Paulo, Sao Paulo, Brazil

Disclosure information not submitted.
RP

Rafael Pandini, MD, MSc

Surgeon
Hospital Israelita Albert Einstein
Sao Paulo, Sao Paulo, Brazil

Disclosure information not submitted.
LG

Lucas Gerbasi, MD

Surgeon
Hospital Israelita Albert Einstein
Sao Paulo, Sao Paulo, Brazil

Disclosure information not submitted.
VS

Victor Seid, MD, PHD

Surgeon
Hospital Israelita Albert Einstein
Sao Paulo, Sao Paulo, Brazil

Disclosure information not submitted.
AP

Ana Sarah Portilho, MD

Surgeon
Hospital Israelita Albert Einstein
Sao Paulo, Sao Paulo, Brazil

Disclosure information not submitted.
LH

Lucas Horcel, MD

Surgeon
Hospital Israelita Albert Einstein
Sao Paulo, Sao Paulo, Brazil

Disclosure information not submitted.
Rocco R. Ricciardi, MD

Chief, Section of Colon and Rectal Surgery
Massachusetts General Hospital
Boston, Massachusetts, United States

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.
LR

Lucas Ramos, n/a

Medical Student
Hospital Israelita Albert Einstein
Sao Paulo, Sao Paulo, Brazil

Disclosure information not submitted.
SS

Sofia Chaves Skaf, n/a

Medical Student
Hospital Israelita Albert Einstein
Sao Paulo, Sao Paulo, Brazil

Disclosure information not submitted.

Senior Author(s)

SA

Sergio Eduardo Araujo, MD, PHD

Staff Colon & Rectal Surgeon
Hospital Israelita Albert Einstein
Sao Paulo, Sao Paulo, Brazil

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.

All of the relevant financial relationships listed below have been mitigated.

Rodrigo de Almeida Leite, MD, MSc: This individual has no financial relationships with ineligible companies.

Rocco R. Ricciardi, MD: This individual has no financial relationships with ineligible companies.

Sergio Eduardo Araujo, MD, PHD: This individual has no financial relationships with ineligible companies.

Image or Table (Do Not add text here):

Purpose/Background: Low Anterior with Total Mesorectal Excision (TME) is the gold-standard treatment for Low Rectal Cancer, addressing the main lymphatic drainage of the rectum. The Lateral Pelvic (LP) lymph node dissection is a technique in use since the 1970’s in the Eastern world, mainly Japan, as an attempt to lower the recurrence of low rectal cancer in the LP wall.The technique for Laparoscopic LP node dissection has been standardized by the authors, showing both acceptable safety profile and good disease control. However, the current indications to perform LP node dissection, that should relate to size and lateral proportion of positive lymph nodes (MRI suspect features), remain unstandardized. Therefore, recommendations of the technique remain unclear, varying according to institutional guidelines.
Our study aims to further analyze the question by reporting the long term recurrence and disease-free survival in patients undergoing LP node dissection in a single center institution, helping to better indicate the procedure and understand its relation to local and distant disease control.

Methods/Interventions: A prospective cohort study of patients undergoing elective surgery for Low Rectal Cancer with LP node Dissection in Albert Einstein Israelite Hospital Sao Paulo, Brazil. All procedures were performed by any of the six experienced oncology surgeons.We included adult (>18 years old) patients diagnosed with low rectal cancer and suspect LP nodes. The inclusion period was from 2019 to 2024.

Results/Outcomes: Thirteen patients were included for analysis, 8 male ( 61.54 %) and 5 female ( 38.46%). Median age was 60 years old (IQR 52-78). Twelve cases had the pathologic diagnosis of rectal adenocarcinoma and 1 patient had Anal Epidermoid Carcinoma diagnosis. No patients was diagnosed with Microsatelite instability. Most patients had T3 or T4 stage ( 76.92 %). Demographics are summarized in Table 1

Most patients included received Low Anterior Resection with Total Mesorectal Excision ( 76.92%) while 3 patients ( 23.08%) received abdominoperineal resection. Median Operative time was 290 minutes ( IQR 180-360) and median in-hospital stay was 3 days (IQR 2-5). Twelve patients (92.31%) received neoadjuvant Chemoradiation and 1 patient had upfront surgery.
Median number of harvested LP nodes was 4 ( IQR 3-5). Of the 13 patients included, only 8 ( 61.54 %) had pathological confirmation of viable tumor on analysis. The number of harvested nodes was not significantly associated with pathologic positive results ( Coef -0.7, IC 95 CI{ -.65 - +.51} p=0.724).

Four patients experienced a local recurrence during follow-up ( 30.77%). All those had positive lateral nodes upon pathological examinations. Only one patient experienced a recurrence in the lateral pelvic wall, with the remainder presenting in the external iliac artery territory. Median time for recurrence was 11 months ( IQR 7-13 months).

Conclusion/Discussion: LPN pathologic positivity was associated with a remarkable reduction in disease-free survival, comparable to metastatic disease, even after adequate LPN resection. MRI had a low accuracy for the diagnosis of viable tumor in LPN. Minimally invasive LPN resection had an acceptable safety profile, with only modest increase in total operative time.