Preoperative ¹⁸F-FDG PET/CT as a surgical triage tool for synchronous neoplasm detection in acute left-sided obstructive colorectal cancer: a two-institution retrospective cohort study.

Authors

Kyung Uk Jung, Sung Ryol Lee, Joosung Park, Hyung Ook Kim, Hungdai Kim, Hee-Sung Song, Ji Young Lee, Yong Bog Kim, Jaemin Jo, Ji Eun Park, Hyun Joo Song, Heung Up Kim, Weon Young Chang, Ho-Kyung Chun, Donghyoun Lee

Published in

Frontiers in surgery. Volume 13. Pages 1871410. Epub Jul 20, 2026.

Abstract

In acute left-sided obstructive colorectal cancer (OCC), the proximal colon cannot be evaluated endoscopically before surgery, and synchronous colorectal cancers (sCRC) and clinically significant neoplasms (CSN) may remain undetected. We evaluated the diagnostic performance of preoperative ¹⁸F-FDG PET/CT for synchronous neoplasm detection in this setting.
This retrospective cohort study included 149 consecutive patients with acute left-sided obstructive colorectal adenocarcinoma (splenic flexure through rectum) treated by primary curative resection at two tertiary centers (2007-2016). Postoperative clearing colonoscopy within 6 months served as the reference standard. PET positivity was defined as focal FDG uptake with SUVmax ≥4.0 in a colorectal segment distinct from the index tumor. The primary endpoint was invasive sCRC; the secondary endpoint was CSN.
Median age was 69 years; 71.1% were male. Invasive sCRC was confirmed in 9 patients (6.0%) and CSN in 17 (11.4%). For invasive sCRC, PET/CT showed sensitivity 77.8%, specificity 95.0%, PPV 50.0%, and NPV 98.5%. For CSN, sensitivity was 52.9%, specificity 96.2%, PPV 64.3%, and NPV 94.1%. Among 135 PET-negative patients, 2 (1.5%) harbored invasive sCRC. Secondary curative resection was required in 5 patients (3.4%) and therapeutic endoscopy in 8 (5.4%).
Preoperative ¹⁸F-FDG PET/CT showed a low rate of missed invasive synchronous cancer when negative (1.5%) and identified a subgroup warranting additional intraoperative assessment when positive. PET/CT is not a substitute for clearing colonoscopy and does not mandate extended resection. These findings are exploratory and require prospective validation.

PMID:
42548845
Bibliographic data and abstract were imported from PubMed on 04 Aug 2026.

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