Target region resection in patients undergoing cytoreductive surgery for peritoneal metastases-is it necessary in absence of visible disease?

Our plain-English summary of Target region resection in patients undergoing cytoreductive surgery for peritoneal metastases-is it necessary in absence of visible disease?, by A. Bhatt, Y. Yonemura, S. Mehta, et al (European Journal of Surgical Oncology, 2020).

The study

• Authors: A. Bhatt, Y. Yonemura, S. Mehta, N. Benzerdjeb, P. Kammar, L. Parikh, M.Y. Shah, S. Shaikh, A. Prabhu, S. Mishra, S. Sinukumar, V. Kepenekian, N. Bakrin, G. Passot, O. Glehen
• Journal: European Journal of Surgical Oncology
• Published: 2020;46(4 Pt A):582-589
• Cited by: 19 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: The aim was to study the patterns of target region (greater omentum, lesser omentum, falciform and umbilical round ligament) involvement in patients undergoing cytoreductive surgery (CRS) from various primary tumors, factors affecting involvement and implications on surgical practice.

Methods: All patients undergoing CRS from July 2018 to December 2018 were included in this prospective study. The incidence of target region involvement in presence and absence of visible disease and the impact of primary tumor site, PCI and other variables on target region involvement was evaluated.

Results: In 191 patients, greater omentum was involved in over 15% of patients irrespective of the primary tumor type and in 15.7% in absence of visible disease. 75% of these had PCI <20. The involvement of the other three target regions was higher than 20% in ovarian cancer, appendiceal tumors and peritoneal mesothelioma. Involvement of these 3 regions was associated with a higher PCI (p < 0.001 for all) and omental involvement (p < 0.001for all). 2.1% of colorectal cancer patients had umbilical round ligament involvement, 4.2% had falciform ligament involvement and none had lesser omentum involvement.

Conclusions: Target region involvement varies according to primary tumour site and disease extent. Resection of the greater omentum should be performed during CRS for PM arising from all primary sites. Resection of other target organs may be performed for selected patients with ovarian cancer, peritoneal mesothelioma and mucinous appendiceal tumors in absence of visible disease. For other patients, it should be done only in presence of visible disease.

Copyright © 2019 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.

In plain English

This prospective study at four centers included 191 patients having cytoreductive surgery, an operation for cancer spread in the abdominal lining (peritoneal metastases), in July to December 2018. The study also included preventive (prophylactic) and second-look operations. It did not study asbestos exposure. Fifteen had peritoneal mesothelioma; others had cancers of the appendix, colon or rectum, ovary, stomach or rarer sites. The authors checked four 'target regions' for tumor: the greater omentum, lesser omentum, umbilical round ligament and falciform ligament. The greater omentum contained tumor in 89 of the 191 patients (46.5%), including 80% with mesothelioma and 19.1% with colorectal cancer. In 14 of these 89 (15.7%), the omental tumor was found without visible disease. The lesser omentum was involved in 46.6% of mesothelioma patients and the umbilical round ligament in more than 25%. Involvement of the three smaller regions was linked to more extensive disease. The authors concluded the greater omentum should be removed for all primary sites, and the other regions may be removed without visible disease in selected patients with ovarian cancer, peritoneal mesothelioma and mucinous appendiceal tumours. They noted small numbers.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Prospective multicenter study (described by the authors as a pilot study) of surgical specimens examined under a fixed pathology protocol
• Who was studied: 191 patients undergoing cytoreductive surgery from various primary tumors, July to December 2018, at four centers (authors' affiliations are in India, Japan and France). The group included patients having prophylactic and second-look surgeries, so that patients with occult disease or no disease could also be studied.
• Exposure: No asbestos exposure was studied. The study compared tumor involvement of target regions by primary tumor site: appendix 49, colorectal 47, ovary 44, stomach 18, peritoneal mesothelioma 15, rare primary 18. It also compared involvement by extent of disease (peritoneal cancer index, PCI).
• Main results:
  • Across all 191 patients, the greater omentum was resected in 155 (81.1%) and involved by tumor in 89 (46.5%).
  • The greater omentum was involved in 80% of the 15 patients with mesothelioma and in 19.1% of the 47 patients with colorectal cancer.
  • Among the 89 patients with greater omentum involvement, 14 (15.7%) had this involvement in the absence of visible disease.
  • The umbilical round ligament was positive for malignancy in 36 patients (18.8%) and negative in 52 (27.2%). It was involved in more than 25% of patients with ovarian cancer, peritoneal mesothelioma and appendiceal cancer, in 2.1% of patients with colorectal cancer, and in no patients with gastric cancer.
  • The lesser omentum was involved in 46.6% of patients with peritoneal mesothelioma, 30.6% with appendiceal tumors and 20.4% with ovarian cancer. It was involved in no patients with colorectal cancer and in one patient (5.6%) with gastric cancer.
  • The falciform ligament was positive in 22 patients (11.5%). Involvement was more than 20% in appendiceal tumors and peritoneal mesothelioma and under 15% in all other tumors (p=0.013).
  • Patients with umbilical round ligament involvement had significantly higher median surgical PCI (p=0.001) and pathological PCI (p less than 0.001). Similar associations with higher PCI were reported for the lesser omentum and falciform ligament.
• The authors' conclusion: The authors concluded that target region involvement varies by primary tumour site and disease extent. In their view, the greater omentum should be resected during cytoreductive surgery for all primary sites. They said the umbilical round ligament, falciform ligament and lesser omentum may be resected without visible disease in selected patients with ovarian cancer, peritoneal mesothelioma and mucinous appendiceal tumours, and only when disease is visible in other patients.
• Limitations the authors state:
  • The study was limited by small numbers, and no sample size calculation was done to ensure adequate power.
  • The authors said the effect of resecting a particular peritoneal region on survival could not be determined.
  • The authors said no conclusions could be drawn on whether to resect the gastroepiploic arch.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Peritoneal mesothelioma.

Medical terms in this study, explained in our Lexicon: Cytoreductive Surgery, Omentum, Ovarian Cancer, Peritoneal Mesothelioma, Omental Involvement, Colorectal Cancer.

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• Repeat Cytoreductive Surgery and HIPEC for Peritoneal Surface Malignancy and Peritoneal Carcinomatosis — J.F. Wong, G.H. Tan, et al. (2015)
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• Long term survival and perioperative propensity score matched outcomes of diaphragmatic resections compared to stripping in cytoreductive surgery + intra-peritoneal chemotherapy — B. Singh, G. Singh, et al. (2020)
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