Incidental detection of colorectal lesions on ¹⁸F-FDG-PET/CT is associated with high proportion of malignancy: A study in 549 patients

Abstract

Background and study aims Further diagnostics of incidental colorectal lesions on ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is questionable. Therefore, we aimed to evaluate the clinical importance of incidentally detected colorectal lesions on FDG-PET/CT.

Patients and methods In the North Denmark Region, a retrospective study was performed among 19,987 patients who had an FDG-PET/CT from January 2006 to December 2015. Among these patients, we identified patients with a colonoscopy within 12 months from the PET/CT scan and a description of incidental colorectal PET-avid lesions on the PET/CT. PET findings were compared with colonoscopy-detected lesions and eventually histopathology.

Results Incidental PET-avid lesions were observed in 549 patients. Colonoscopy revealed lesions in 457 (83 %), among whom 338 patients had a final histopathological diagnosis. Malignant and premalignant lesions were found in 297 patients (54 % among patients with a PET-avid lesion). The lesions were cancer in 76 patients and adenoma in 221 patients of whom 30 had high-grade and 191 low-grade adenomas. The findings changed patient management in 166 cases (30 % of all patients with a PET-avid lesion). A colonoscopy-based surveillance program was initiated for 80 % of patients with high-grade adenoma. No patients with PET-avid lesions but normal colonoscopy developed colorectal cancer during 3 years of observation (median observation time 7 years).

Conclusions Incidental colorectal FDG uptake was infrequently observed, but when present, it was associated with a high rate of malignant or premalignant lesions. Our results indicate that patients with incidental colorectal FDG uptake should be referred to diagnostic work-up including colonoscopy.

Publication History

Received: 28 February 2020

Accepted: 18 August 2020

Article published online:
17 November 2020

• References

• 1 El-Galaly T, Villa D, Gormsen L. et al. FDG-PET/CT in the management of lymphomas: current status and future directions. J Intern Med 2018; 284: 358-376
• 2 Divisi D, Barone M, Zaccagna G. et al. Fluorine-18 fluorodeoxyglucose positron emission tomography in the management of solitary pulmonary nodule: a review. Ann Med 2017; 49: 626-635
• 3 Perng P, Marcus C, Subramaniam R. (18)F-FDG-PET/CT and melanoma: staging, immune modulation and mutation-targeted therapy assessment, and prognosis. AJR Am J Roentgenol 2015; 205: 259-270
• 4 Dinnes J, Bancos I, Di Ruffano LF. et al. Management of endocrine disease: Imaging for the diagnosis of malignancy in incidentally discovered adrenal masses: A systematic review and meta-analysis. Eur J Endocrinol 2016; 175: 51-64
• 5 Gedberg N, Karmisholt J, Gade M. et al. The frequency of focal thyroid incidental findings and risk of malignancy detected by 18F-Fluorodeoxyglucose positron emission tomography in an iodine deficient population. Diagnostics (Basel) 2018; 8 pii: E46
• 6 Uppal A, White M, Nagar S. et al. Benign and malignant thyroid incidentalomas are rare in routine clinical practice: a review of 97,908 imaging studies. Cancer Epidemiol Biomarkers Prev 2015; 24: 1327-1331
• 7 Kousgaard S, Thorlacius-Ussing O. Incidental colorectal FDG uptake on PET/CT scan and lesions observed during subsequent colonoscopy: a systematic review. Tech Coloproctol 2017; 21: 521-529
• 8 Pandit-Taskar N, Schöder H, Gonen M. et al. Clinical significance of unexplained abnormal focal FDG uptake in the abdomen during whole-body PET. Am J Roentgenol 2004; 183: 1143-1147
• 9 Treglia G, Bertagna F, Sadeghi R. et al. Prevalence and risk of malignancy of focal incidental uptake detected by fluorine-18-fluorodeoxyglucose positron emission tomography in the parotid gland: a meta-analysis. Eur Arch Oto-Rhino-Laryngology 2014; 272: 3617-3626
• 10 Na S-Y, Kim K-J, Han S. et al. Who should undergo a colonoscopy among patients with incidental colon uptake on PET-CT?. Scand J Gastroenterol 2015; 5521: 1-9
• 11 Abdel-Nabi H, Doerr RJ, Lamonica DM. et al. Staging of primary colorectal carcinomas with fluorine-18 fluorodeoxyglucose whole-body PET: correlation with histopathologic and CT findings. Radiology 1998; 206: 755-760
• 12 Prabhakar HB, Sahani DV, Fischman AJ. et al. Bowel hot spots at PET-CT. Radiographics 2007; 27: 145-159
• 13 Zasadny KR, Wahl RL. Standardized uptake values of normal tissues at PET with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose: variations with body weight and a method for correction. Radiology 1993; 189: 847-850
• 14 Cook GJR, Fogelman I, Maisey MN. Normal physiological and benign pathological variants of 18-fluoro-2-deoxyglucose positron-emission tomography scanning: Potential for error in interpretation. Semin Nucl Med 1996; 26: 308-314
• 15 Seivert M, Plomteux O, Colard A. et al. Endoscopic findings in case of incidental colonic uptake in PET-CT how to improve PET-CT specificity?. Acta Gastroenterol Belg 2014; 77: 413-417
• 16 Farquharson AL, Chopra A, Ford A. et al. Incidental focal colonic lesions found on 18Fluorodeoxyglucose positron emission tomography/computed tomography scan: Further support for a national guideline on definitive management. Color Dis 2012; 14: 56-63
• 17 Salazar AndíaG, Prieto SorianoA, Ortega CandilA. et al. Clinical relevance of incidental finding of focal uptakes in the colon during 18F-FDG-PET/CT studies in oncology patients without known colorectal carcinoma and evaluation of the impact on management. Rev española Med Nucl e imagen Mol 2012; 31: 15-21
• 18 Lee JC, Hartnett GF, Hughes BGM. et al. The segmental distribution and clinical significance of colorectal fluorodeoxyglucose uptake incidentally detected on PET-CT. Nucl Med Commun 2009; 30: 333-337
• 19 Strum W. Colorectal Adenomas. N Engl J Med 2016; 374: 1065-75
• 20 Schlemper R, Riddell R, Kato Y. et al. The Vienna classification of gastrointestinal epithelial neoplasia. Gut 2000; 47: 251-255
• 21 Colucci PM, Yale SH, Rall CJ. Colorectal Polyps. Clin Med Res 2003; 1: 261-262
• 22 Strate LL, Modi R, Cohen E. et al. Diverticular disease as a chronic illness: evolving epidemiologic and clinical insights. Am J Gastroenterol 2012; 107: 1486-1493
• 23 Atkin WS, Saunders BP. Surveillance guidelines after removal of colorectal adenomatous polyps. Gut 2002; 51: 6-9
• 24 Lin M, Koo JH, Abi-Hanna D. Management of patients following detection of unsuspected colon lesions by PET imaging. Clin Gastroenterol Hepatol 2011; 9: 1025-1032
• 25 Valente M. Endoscopic and histopathological analysis of incidental focal colorectal 18 F-fluorodeoxyglucose uptake in PET/CT scan: Colonoscopic evaluation is warranted. Am J Surg 2018; 215: 379-381
• 26 Shim JH, O. JH, Oh SIl. et al. Clinical significance of incidental colonic 18F-FDG Uptake on PET/CT images in patients with gastric adenocarcinoma. J Gastrointest Surg 2012; 16: 1847-1853
• 27 Treglia G, Calcagni ML, Rufini V. et al. Clinical significance of incidental focal colorectal 18F-fluorodeoxyglucose uptake: Our experience and a review of the literature. Color Dis 2012; 14: 174-180
• 28 Israel O, Yefremov N, Bar-Shalom R. et al. PET/CT detection of unexpected gastrointestinal foci of 18F-FDG uptake: incidence, localization patterns, and clinical significance. J Nucl Med 2005; 46: 758-762
• 29 Kei PL, Vikram R, Yeung HWD. et al. Incidental finding of focal FDG uptake in the bowel during PET/CT: CT features and correlation with histopathologic results. Am J Roentgenol 2010; 194: 401-406
• 30 Garrido Durán C, Payeras Capó M, García Caparrós C. et al. Clinical-endoscopic relevance of incidental colorectal lesions detected by PET-CT. Rev Esp Enferm Dig 2018; 110: 434-439