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
2674 - Multicenter Phase I Trial of Trastuzumab Emtansine (T-DM1) in Combination with Non-Pegylated Liposomal Doxorubicin (NPLD) in HER2[+] Metastatic Breast Cancer (MBC). THELMA Study
Presenter: Elena López-Miranda
Session: Poster Display session 2
Resources:
Abstract
1398 - Phase 1 study of liposomal formulation of eribulin (E7389-LF) in patients (pts) with advanced solid tumors: primary results of dose-escalation part
Presenter: Noboru Yamamoto
Session: Poster Display session 2
Resources:
Abstract
5818 - Polo-like Kinase 1 inhibitor onvansertib synergizes with paclitaxel in breast cancer carrying p53 mutation
Presenter: Antonio Giordano
Session: Poster Display session 2
Resources:
Abstract
5927 - Phase 1b study of heat shock protein 90 inhibitor, onalespib in combination with paclitaxel in patients with advanced, triple negative breast cancer (NCT02474173).
Presenter: Robert Wesolowski
Session: Poster Display session 2
Resources:
Abstract
1695 - Impact of pertuzumab and T-DM1 on prognosis of HER2-positive metastatic breast cancer (MBC) and factors affecting their efficacy: results from the AGMT_MBC-Registry
Presenter: Simon Peter Gampenrieder
Session: Poster Display session 2
Resources:
Abstract
1742 - Clinical profile and outcome of HER2 positive breast cancer patients with brain metastases treated with HER2 targeted therapy: Real world experience.
Presenter: Prabhat Bhargava
Session: Poster Display session 2
Resources:
Abstract
1846 - Pertuzumab, trastuzumab, and docetaxel for HER2-positive metastatic breast cancer: results of single arm phase IV COMACHI study
Presenter: Norikazu Masuda
Session: Poster Display session 2
Resources:
Abstract
5385 - Anti HER-2 Therapies and Left Ventricular Dysfunction The Renaissance Study
Presenter: ANDRES DANIELE
Session: Poster Display session 2
Resources:
Abstract
3320 - Safety and efficacy of T-DM1 in 128 patients with advanced HER2+ breast cancer: The Royal Marsden experience.
Presenter: Nicolò Battisti
Session: Poster Display session 2
Resources:
Abstract
4540 - Use of trastuzumab emtansine (T-DM1; K) after pertuzumab + trastuzumab (PH) in patients with HER2-positive metastatic breast cancer (mBC): challenges in assessing effectiveness of treatment sequencing in the real world (RW)
Presenter: Thibaut Sanglier
Session: Poster Display session 2
Resources:
Abstract