Abstract 2747
Background
Guidelines for rectal cancer treatment differ in Japan, Europe, and the United States. Neoadjuvant chemoradiotherapy (CRT) has been used to control lateral lymph nodes (LLNs) in the West. The usefulness of LLN dissection (LLND) has been discussed in Japan, and a randomized study stated the possible advantage of local control. However, it is still unclear whether adding LLND to CRT is beneficial.
Methods
To investigate the effectiveness of LLND on rectal cancer patients who underwent neoadjuvant CRT, we retrospectively collected magnetic resonance images (MRIs) in a cohort of 1500 patients with cStage II/III lower rectal cancer below the peritoneal reflection and centrally reviewed MRIs. We measured short-axis LLN sizes on pre- and post-CRT images and evaluated patients’ prognosis according to LLN size and whether LLND was performed.
Results
MRIs were collected from 752 patients, of whom 189 underwent neoadjuvant CRT. Both pre- and post-CRT MRIs were available in 155 patients, of whom 66 underwent LLND (LLND group) and 89 did not (non-LLND group). The LLND and non-LLND group showed the following differences: positive circumferential resection margin by MRI after CRT: 53.0% vs. 32.6%; positive extramural venous invasion: 36.4% vs. 24.7%; laparoscopic surgery: 39.4% vs. 88.8%; and mean pre-CRT LLN size: 5.2 mm vs. 3.6 mm. Five-year relapse-free survival (5y-RFS) was 73.8% and 66.1% in the LLND and non-LLND groups, respectively (p = 0.38). Two local recurrences occurred in the LLND group. In stratified analysis, 5y-RFS of 40 patients whose LLN size was ≥5 mm in pre-CRT images was 77.8% in the LLND group and 46.2% in the non-LLND group (p = 0.06). On the other hand, 115 patients whose LLN size was <5 mm in pre-CRT images showed almost no difference between the LLND and non-LLND group (5y-RFS: 71.1% vs. 69.5%, p = 0.85).
Conclusions
Our data indicated that adding LLND to CRT may have survival benefits on those who had LLN size of ≥ 5 mm before CRT. Stratification by short-axis LLN size using pre-CRT MRIs may facilitate optimal multidisciplinary treatment strategies for low rectal cancer.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Department of Surgery, Kyoto University Graduate School of Medicine.
Funding
The Japanese Foundation for Research and Promotion of Endoscopy, The Japan Society of Clinical Oncology, and Kondou Kinen Medical Foundation.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
1025 - Liver metastases (LM) from intrahepatic cholangiocarcinoma (iCCA): Outcomes from the European Network for the Study of Cholangiocarcinoma (ENS-CCA) registry and implications on current American Joint Committee on Cancer (AJCC) staging.
Presenter: Angela Lamarca
Session: Poster Display session 2
Resources:
Abstract
5813 - Is MGMT methylation a new therapeutic target for Biliary Tract Cancer?
Presenter: Monica Niger
Session: Poster Display session 2
Resources:
Abstract
5839 - Biliary Tract Cancers in Portuguese families with BRCA gene mutation: a retrospective study.
Presenter: Patricia Pereira
Session: Poster Display session 2
Resources:
Abstract
4338 - Selection of patients with hepatocellular carcinoma for selective internal radiation therapy based on tumour burden and liver function: a post-hoc analysis of the SARAH trial
Presenter: Daniel Palmer
Session: Poster Display session 2
Resources:
Abstract
1700 - Second-line chemotherapy (SLC) in Patients with Advanced Biliary tract and Gallbladder Cancers (ABGC) Prolongs Survival: A Retrospective Population-based Cohort Study
Presenter: Adnan Zaidi
Session: Poster Display session 2
Resources:
Abstract
5562 - Overall survival of patients with hepatocellular carcinoma receiving sorafenib versus selective internal radiation therapy with predicted dosimetry in the SARAH trial
Presenter: Neil Hawkins
Session: Poster Display session 2
Resources:
Abstract
1838 - Multicenter phase II trial of axitinib monotherapy for advanced biliary tract cancer refractory to gemcitabine-based chemotherapy
Presenter: Naohiro Okano
Session: Poster Display session 2
Resources:
Abstract
3641 - Soluble Programmed Death-ligand 1 indicate poor prognosis in hepatocellular carcinoma patients undergoing transcatheter arterial chemoembolization
Presenter: Xiaolu Ma
Session: Poster Display session 2
Resources:
Abstract
2733 - The Prognostic Nutritional Index (PNI) is an independent predictor of survival in advanced biliary cancers (ABC) receiving first-line chemotherapy (1L).
Presenter: Francesco Caputo
Session: Poster Display session 2
Resources:
Abstract
3773 - Impact of centralisation of national cancer services on patient outcomes for hepatobiliary cancers in Ireland 2000 – 2016
Presenter: David O Reilly
Session: Poster Display session 2
Resources:
Abstract