Incidental findings on positron emission tomography/CT scans performed in the investigation of lung cancer

Abstract

Objectives: This study aimed to clarify the number and cause of incidental findings detected on positron emission tomography (PET)/CT in patients undergoing investigation for presumed lung cancer. Methods: The scan reports from PET/CT studies performed for patients with lung cancer under National Institute for Clinical Evidence guidelines from January 2006 until March 2008 were retrospectively reviewed. Incidental findings were followed up by a combination of case note review, clinician feedback, colonoscopy database, histopathology and follow-up imaging. Results: 818 patients were investigated for lung cancer in the study period. 197 incidental findings were found in 175 (21%) patients. The subsequent investigation of 108 lesions confirmed a pathological correlation in 71 (66%) cases. A second primary malignancy was found in 10 patients within the bowel (6), breast (2), tongue (1) and stomach (1). A pre-malignant lesion was confirmed in 25 cases (24 large bowel tubulovillous adenomas and a follicular thyroid lesion). A further 41 (5%) benign abnormalities were detected at multiple sites; the thyroid gland was the single most frequently affected site (14 abnormalities). There were 36 (4.4%) false-positive reported findings, including 17 in the region of the pharynx and larynx and 12 within the large bowel. Conclusions: Overall, 9.2% of patients with suspected or known lung cancer having PET/CT had a confirmed incidental finding. A malignant or pre-malignant lesion was found in 1.2% and 3.0%, respectively. These were mostly located within the gastrointestinal tract. The majority of false-positive incidental findings were located in the larynx and pharynx. Uptake in these regions is unlikely to be significant in the absence of a CT morphological correlation.

Multicentric study on 18F-FDG-PET/CT breast incidental uptake in patients studied for non-breast malignant purposes

“…[9][10][11][12][13][14][15][16][17][18][19][20][21][22] Results on the prevalence of BIU and their malignancy rate in the most important studies and in the present are summarised in Table 1 The nodule at CT was 20 mm of diameter, SUV max was 2.7, BIU to liver ratio was 0.9 and BIU to blood-pool ratio was 0.5. After biopsy the final diagnosis was fibroadenoma.…”

“…Breast lesions in the remaining 11 patients, who showed no further evidence of breast malignancy over at least 2-years follow-up, were considered to be clinically benign. Chopra et al 10 19 retrospectively reviewed 7594 consecutive women; forty-three patients (0.6%) had incidental hypermetabolic lesions in the breast; thirteen patients were lost to imaging follow-up; finally, 30 patients with 33 BIUs 17 of which underwent gun biopsy or excision biopsy, confirming nine malignancies and eight benign lesions. The remaining 16 lesions underwent imaging follow-up for at least 2 years documenting benign lesions.…”

“…8 Despite screening procedures, the available data reporting BIU detected by 18 F-FDG-PET or PET/CT suggest that some lesions are still missed during traditional screening work-up. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] When a BIU is detected, it creates for a management dilemma requiring further investigations. Overall, the prevalence of BIU on all scan ranges from 0.11% to 0.83%, with pooled estimate of 0.40%; the prevalence of BIU on scans performed on female patients only ranges from 0.36% to 1.84%, with pooled estimate of 0.82%; the pooled malignancy risk of BIU who undergo further investigations ranges from 18% to 100% with pooled estimate of 48%; the pooled malignancy risk of BIU who undergo histological examination ranges from 51% to 100% with pooled estimate of 60%.…”

Rendimiento del Positron Emission Tomography/Computed Tomography (PET/CT) en etapificación de cáncer pulmonar

“…Esta cifra es similar al 14% encontrado en otras series estudiadas con TCc 17 . La ocurrencia de una segunda neoplasia primaria sincrónica al cáncer pulmonar ha sido mencionada en algunas publicaciones, con frecuencias algo menores a la encontrada en nuestra muestra, entre 1,7 y 4,2% de los pacientes [18][19][20] . Ya que un número importante de los hallazgos incidentales del PET/CT no fueron confirmados histológicamente, es posible que nuestro estudio subestime la ocurrencia de segundas neoplasias primarias asociadas al cáncer pulmonar, e incluso de metástasis en ubicación inhabitual.…”

“…Ya que un número importante de los hallazgos incidentales del PET/CT no fueron confirmados histológicamente, es posible que nuestro estudio subestime la ocurrencia de segundas neoplasias primarias asociadas al cáncer pulmonar, e incluso de metástasis en ubicación inhabitual. Esto se constituye como una limitación de nuestro estudio, que se replica en otras publicaciones, donde 37-45% de los "incidentalomas" del PET/CT no son confirmados 20 .…”