[Skip to Content]
[Skip to Content Landing]
Views 1,339
Citations 0
Original Investigation
July 3, 2019

Lateral Nodal Features on Restaging Magnetic Resonance Imaging Associated With Lateral Local Recurrence in Low Rectal Cancer After Neoadjuvant Chemoradiotherapy or Radiotherapy

Author Affiliations
  • 1Department of Surgery, Leiden University Medical Center, Leiden, the Netherlands
  • 2Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
  • 3Department of Gastroenterological Surgery, Cancer Institute Hospital of Japanese Foundation for Cancer Research, Tokyo, Japan
  • 4Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, New York
  • 5Department of Surgery, Netherlands Cancer Institute, Amsterdam, the Netherlands
  • 6Department of Colorectal Surgery, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
  • 7Center for Digestive Diseases, Department of Molecular Medicine and Surgery, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
  • 8Department of Gastroenterological Surgery, Toranomon Hospital, Tokyo, Japan
  • 9Department of Surgery, Seoul St Mary’s Hospital, The Catholic University of Korea, Seoul, Republic of Korea
  • 10Department of Surgery, Royal Adelaide Hospital, University of Adelaide, Adelaide, South Australia, Australia
  • 11Department of Colorectal Surgery, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
  • 12Surgical Outcomes Research Center (SOuRCe), Sydney Local Health District, Sydney School of Public Health, University of Sydney, Sydney, New South Wales, Australia
  • 13Department of Medical Statistics, Leiden University Medical Center, Leiden, the Netherlands
  • 14Department of Surgery, Catharina Hospital, Eindhoven, the Netherlands
  • 15School of Oncology and Developmental Biology (GROW), Maastricht University, Maastricht, the Netherlands
  • 16Department of Surgery, Amsterdam University Medical Centers, location VUmc, Amsterdam, the Netherlands
JAMA Surg. 2019;154(9):e192172. doi:10.1001/jamasurg.2019.2172
Key Points

Question  What is the role of restaging magnetic resonance imaging (MRI) after chemoradiotherapy or radiotherapy, and which specific patients might benefit from a lateral lymph node dissection (LLND)?

Findings  In this multicenter pooled cohort study including 741 patients with low rectal cancer after chemoradiotherapy or radiotherapy, shrinkage of lateral nodes from a short-axis node size of 7 mm or greater on primary MRI to a short-axis node size of 4 mm or less on restaging MRI abolished the risk of lateral local recurrence (LLR). However, in persistently enlarged nodes (greater than 4 mm) in the internal iliac compartment on restaging MRI, the risk of LLR was high, and an LLND lowered this risk significantly.

Meaning  Persistently enlarged nodes in the internal iliac compartment indicate a high risk of LLR, and an LLND should be seriously considered in these patients.

Abstract

Importance  Previously, it was shown in patients with low rectal cancer that a short-axis (SA) lateral node size of 7 mm or greater on primary magnetic resonance imaging (MRI) resulted in a high lateral local recurrence (LLR) rate after chemoradiotherapy or radiotherapy ([C]RT) with total mesorectal excision (TME) and that this risk was lowered by a lateral lymph node dissection (LLND). The role of restaging MRI after (C)RT with regard to LLR risk and which specific patients might benefit from an LLND is not fully understood.

Objective  To determine the factors on primary and restaging MRI that are associated with LLR in low rectal cancer after (C)RT and to formulate specific guidelines on which patients might benefit from an LLND.

Design, Setting, and Participants  In this retrospective, multicenter, pooled cohort study, patients who underwent surgery for cT3 or cT4 low rectal cancer with a curative intent from 12 centers in 7 countries from January 2009 to December 2013 were included. All patients’ MRIs were rereviewed according to a standardized protocol, with specific attention to lateral nodal features. The original cohort included 1216 patients. For this study, patients who underwent (C)RT and had a restaging MRI were selected, leaving 741 for analyses across 10 institutions, including 651 who underwent (C)RT with TME and 90 who underwent (C)RT with TME and LLND.

Main Outcomes and Measures  The main purpose was to identify the factors on primary and restaging MRI associated with LLR after (C)RT with TME. Whether high-risk patients might benefit in terms of LLR reduction from an LLND was also studied.

Results  Of the 741 included patients, 480 (64.8%) were male, and the mean (SD) age was 60.4 (12.0) years. An SA lateral node size of 7 mm or greater on primary MRI resulted in a 5-year LLR rate of 17.9% after (C)RT with TME. At 3 years, there were no LLRs in 28 patients (29.2%) with lateral nodes that were 4 mm or less on restaging MRI. Nodes that were 7 mm or greater on primary MRI and greater than 4 mm on restaging MRI in the internal iliac compartment resulted in a 5-year LLR rate of 52.3%, significantly higher compared with nodes in the obturator compartment of that size (9.5%; hazard ratio, 5.8; 95% CI, 1.6-21.3; P = .003). Compared with (C)RT with TME alone, treatment with (C)RT with TME and LLND in these unresponsive internal nodes resulted in a significantly lower LLR rate of 8.7% (hazard ratio, 6.2; 95% CI, 1.4-28.5; P = .007).

Conclusions and Relevance  Restaging MRI is important in clinical decision making in lateral nodal disease. In patients with shrinkage of lateral nodes from an SA node size of 7 mm or greater on primary MRI to an SA node size of 4 mm or less on restaging MRI, which occurs in about 30% of cases, LLND can be avoided. However, persistently enlarged nodes in the internal iliac compartment indicate an extremely high risk of LLR, and an LLND lowered LLR in these cases.

Limit 200 characters
Limit 25 characters
Conflicts of Interest Disclosure

Identify all potential conflicts of interest that might be relevant to your comment.

Conflicts of interest comprise financial interests, activities, and relationships within the past 3 years including but not limited to employment, affiliation, grants or funding, consultancies, honoraria or payment, speaker's bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued.

Err on the side of full disclosure.

If you have no conflicts of interest, check "No potential conflicts of interest" in the box below. The information will be posted with your response.

Not all submitted comments are published. Please see our commenting policy for details.

Limit 140 characters
Limit 3600 characters or approximately 600 words
    ×