Intraoperative fluorescence imaging in thoracic surgery

Our plain-English summary of Intraoperative fluorescence imaging in thoracic surgery, by A.D. Newton, J.D. Predina, S. Nie, et al (Journal of Surgical Oncology, 2018).

The study

• Authors: A.D. Newton, J.D. Predina, S. Nie, P.S. Low, S. Singhal
• Journal: Journal of Surgical Oncology
• Published: 2018;118(2):344-355
• Type of article: Review
• Cited by: 56 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Intraoperative fluorescence imaging (IFI) can improve real-time identification of cancer cells during an operation. Phase I clinical trials in thoracic surgery have demonstrated that IFI with second window indocyanine green (TumorGlow® ) can identify subcentimeter pulmonary nodules, anterior mediastinal masses, and mesothelioma, while the use of a folate receptor-targeted near-infrared agent, OTL38, can improve the specificity for diagnosing tumors with folate receptor expression. Here, we review the existing preclinical and clinical data on IFI in thoracic surgery.

© 2018 Wiley Periodicals, Inc.

In plain English

This article was a review, not a new study. The authors summarized earlier animal and human research, much of it by their own group, on intraoperative fluorescence imaging. In this technique, a fluorescent dye makes tumor tissue, or lymph nodes draining a tumor, glow under a special camera during chest cancer surgery. The review covered three dyes: indocyanine green (given by a second window technique the authors named TumorGlow®), EC17 and OTL38. For malignant pleural mesothelioma, they described a pilot study in which surgeons first tried to remove all disease by sight and touch. Imaging then found additional disease deposits in all 8 patients, a mean of 1.8 per patient, ranging from 0.3 to 2.2 cm. In a 50-patient lung nodule study, 95.6% (65/68) of malignant nodules fluoresced with OTL38. The authors named limited depth of penetration as a major limitation, along with indocyanine green building up in inflamed tissue. They concluded that pilot and phase I trials have shown the technique is feasible, and that phase II and III trials are needed to determine its efficacy and effect on patient outcomes.

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: Review of existing preclinical and clinical data
• Who was studied: Previously published preclinical studies (mice, dogs, cadaveric human lungs) and clinical studies of fluorescence imaging in patients having thoracic surgery. The patients had lung nodules, lung metastases, lung or esophageal cancer lymph node mapping, mediastinal masses, or mesothelioma. Much of the work came from the authors' own group. No search method or time period was stated.
• Exposure: No asbestos or other occupational exposure was studied. The review concerns fluorescent imaging dyes used during surgery: indocyanine green (ICG), and the receptor-targeted agents EC17 and OTL38.
• Main results:
  • Reviewed mesothelioma pilot study: patients were given intravenous ICG at 5 mg/kg 24 hours before pleurectomy and decortication. In all of the first 8 patients, imaging found additional disease deposits after surgeons believed debulking was complete.
  • In those 8 mesothelioma patients, there was a mean of 1.8 additional deposits per patient, ranging from 0.3 to 2.2 cm in size.
  • Reviewed lung nodule study of TumorGlow®: in 18 patients, 14 of 18 primary nodules were identified in place during surgery.
  • Reviewed OTL38 study of 50 patients: 92.0% (69/75) of all nodules and 95.6% (65/68) of malignant nodules fluoresced.
  • In the same OTL38 study, 100% (15/15) of malignant nodules smaller than 1 cm fluoresced, while only 26.7% (4/15) showed up on FDG-PET scanning.
  • Reviewed EC17 'optical biopsy' study of 30 patients with indeterminate lung nodules: sensitivity and specificity for pulmonary adenocarcinoma were both 100% (19/19 and 11/11).
  • For sentinel lymph node mapping, ICG is injected around the tumor, and the imaging highlights the lymphatic channels and nodes that drain it.
• The authors' conclusion: The authors concluded that pilot and phase I clinical trials have shown that fluorescence imaging for thoracic cancers is feasible. They added that more phase II and III trials are needed to determine its efficacy, its impact on patient outcomes and its overall clinical value.
• Limitations the authors state:
  • Depth of penetration is a major limitation of the technique.
  • ICG has suboptimal specificity because it accumulates in inflamed tissue.
  • Efficacy and effects on patient outcomes have not yet been established and need phase II and III trials.

Topics

Medical terms in this study, explained in our Lexicon: Thoracic Surgery, Clinical Trial, Mesothelioma.

Related studies

• Thirty-day mortality underestimates the risk of early death after major resections for thoracic malignancies — R.R. McMillan, A. Berger, et al. (2014)
• Follow-up of patients with resected thoracic malignancies — P.M. Claiborne, C.S. Fowler, et al. (2012)
• Thoracic cancer surgery in the elderly — J. Hasse, H. Wertzel, et al. (1998)
• PET scan contribution in chest tumor management: a systematic review for thoracic surgeons — L. Duranti, F. Leo, et al. (2012)
• ¹⁸F-FDG uptake on PET is a predictive marker of thymidylate synthase expression in patients with thoracic neoplasms — K. Kaira, N. Yamamoto, et al. (2014)
• The role of thoracic surgery in the management of mesothelioma: an expert opinion on the limited evidence — P. Bertoglio, D.A. Waller (2016)

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