Preoperative computed tomography does not predict resectability in peritoneal carcinomatosis

Our plain-English summary of Preoperative computed tomography does not predict resectability in peritoneal carcinomatosis, by J.D. Rivard, W.J. Temple, Y.J. McConnell, et al (American Journal of Surgery, 2014).

The study

• Authors: J.D. Rivard, W.J. Temple, Y.J. McConnell, H. Sultan, L.A. Mack
• Journal: American Journal of Surgery
• Published: 2014;207(5):760-4; discussion 764-5
• Cited by: 51 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: Obtaining a complete cytoreduction in patients with peritoneal carcinomatosis (PC) is one of the most significant prognostic variables for long-term survival. This study explored features on preoperative computed tomography (CT) to predict unresectability.

Methods: A retrospective case-control study was conducted of 15 patients with unresectable PC and 15 patients with completely resected PC matched by intraoperative peritoneal cancer index (PCI) and pathology type. Two surgical oncologists blindly analyzed all abdominopelvic CT scans.

Results: PCI estimated on imaging was not higher in unresectable patients (P = .851) and significantly underestimated intraoperative PCI measurement (P = .003). No single concerning feature was associated with unresectability. However, patients with 2 or more concerning features were more likely to be unresectable (87.5% vs 36.4%, P = .035).

Conclusions: Two or more concerning CT imaging features appear to be associated with a higher risk of unresectability in patients with PC. However, no specific imaging feature should exclude a patient from an attempted cytoreduction.

Copyright © 2014 Elsevier Inc. All rights reserved.

In plain English

This retrospective case-control study from the University of Calgary, Canada, asked whether features on preoperative CT scans could predict which patients with peritoneal carcinomatosis (cancer spread on the abdominal lining) could not have all visible tumor removed at surgery. The article does not mention asbestos. Fifteen patients found unresectable during surgery between 2007 and 2011 were matched with 15 whose tumor was completely removed. Each group had 8 colorectal cancer patients, 1 mesothelioma patient, and 6 patients with appendix tumors. Two surgical oncologists reviewed the scans blinded, in random order. The CT-based disease score underestimated the score measured at surgery (median 25.5 versus 39) and was not higher in unresectable patients. No single concerning CT feature was linked to unresectability. Of 8 patients with 2 or more concerning features, 7 were unresectable. Of 22 with fewer, 8 (36.4%) were. The authors concluded that 2 or more concerning features appear to be associated with a higher risk of unresectability, but that no specific imaging feature should exclude a patient from attempted surgery. They noted the small sample, and that the scan readers were the operating surgeons.

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: retrospective case-control study (cases matched by intraoperative peritoneal cancer index and pathology type), with blinded review of CT scans
• Who was studied: 30 patients with peritoneal carcinomatosis operated on at the University of Calgary between 2007 and 2011. The 15 unresectable patients (CCR-2) were matched to 15 completely cytoreduced patients (CCR-0). Each group had 8 colorectal cancer, 1 high-grade appendix cancer, 3 low-grade appendix cancer, 1 mesothelioma and 2 appendix adenocarcinoid patients.
• Exposure: No asbestos or fiber exposure was studied. The factor examined was findings on preoperative contrast-enhanced abdominal and pelvic CT scans, read blindly by 2 surgical oncologists. These findings were the estimated peritoneal cancer index, concerning features (bowel obstruction, ascites, retroperitoneal lymphadenopathy, pelvic side wall involvement, portal involvement, bilateral hydroureter, liver and lung metastases) and likelihood-of-resectability scores.
• Main results:
  • Across all 30 patients, the CT-estimated peritoneal cancer index underestimated the index measured at surgery (median CT-PCI 25.5, IQR 11.25 to 36.75, versus median intraoperative PCI 39, IQR 24.75 to 39; P = .003). The authors reported good correlation (r2 = .67).
  • The CT-estimated index was not higher in unresectable patients (CCR-2 median 23, IQR 12 to 30) than in completely cytoreduced patients (CCR-0 median 27, IQR 7 to 39; P = .851).
  • At least one concerning imaging feature was seen in 87% of resectable patients and 93% of unresectable patients (P = 1.00). No single concerning feature was associated with unresectability.
  • Of 8 patients with 2 or more concerning CT features, 7 (87.5%) were in the unresectable group (P = .04 in the results, P = .035 in the abstract). Of 22 patients with fewer than 2 features, 8 (36.4%) were unresectable. Patients with 3 concerning features were seen only in the unresectable group.
  • Median likelihood-of-resectability scores were similar between groups. Based on imaging alone, the median was 2 in both (P = .76). After clinical information was added, the median was again 2 in both (P = .93).
• The authors' conclusion: The authors concluded that CT underestimates the intraoperative peritoneal cancer index. They also concluded that 2 or more concerning CT features appear to be associated with a higher risk of unresectability, but that no specific imaging feature should exclude a patient from an attempted cytoreduction.
• Limitations the authors state:
  • The sample size was small.
  • The 2 surgeons who read the CT scans were the same surgeons who performed the operations.
  • Numbers were limited by matching resectable and unresectable patients on intraoperative PCI and pathologic type.
  • There was a median of 2 months between preoperative imaging and surgery.
  • Specific patient symptoms were not prospectively collected, so a published peritoneal disease severity score could not be analyzed.

Topics

Medical terms in this study, explained in our Lexicon: Cytoreductive Surgery, Case-Control Study, Unresectable, Peritoneal Cancer Index (PCI), Pathology, CT Scan.

Related studies

• Preoperative Circulating Tumor DNA in Patients with Peritoneal Carcinomatosis is an Independent Predictor of Progression-Free Survival — J.M. Baumgartner, V.M. Raymond, et al. (2018)
• Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for peritoneal carcinomatosis: the Danish experience — L.H. Iversen, P.C. Rasmussen, et al. (2013)
• Evolution of locoregional treatment for peritoneal carcinomatosis: single-center experience of 308 procedures of cytoreductive surgery and perioperative intraperitoneal chemotherapy — T.C. Chua, W. Liauw, et al. (2011)
• CT differentiation of diffuse malignant peritoneal mesothelioma and peritoneal carcinomatosis — Y.F. Liang, G.Q. Zheng, et al. (2016)
• Multicenter comprehensive methodological and technical analysis of 832 pressurized intraperitoneal aerosol chemotherapy (PIPAC) interventions performed in 349 patients for peritoneal carcinomatosis treatment: An international survey study — M. Nowacki, M. Alyami, et al. (2018)
• 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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