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Efficacy of 18F-FDG PET/CT in investigation of elevated CEA without known primary malignancy

View Article: PubMed Central - PubMed

ABSTRACT

Aim:: To evaluate the efficacy of 18flurodeoxyglucose positron emission tomography/computer tomography (18F-FDG PET/CT) in investigating patients with elevated carcinoembryonic antigen (CEA) and without known primary malignancy, and the impact of PET/CT findings on patient management.

Setting and design:: PET/CT scans done in a tertiary hospital between December 2007 and February 2012 for elevated CEA in patients without known primary malignancy were retrospectively reviewed.

Materials and methods:: The PET/CT findings, patients' clinical information, level of CEA, histological diagnosis, and subsequent management were retrieved by the electronic patient record for analysis.

Statistical analysis:: Data were analyzed using SPSS version 19.

Results:: One hundred and one PET/CT scans were performed for patients with elevated CEA. Fifty-eight of these were performed for patients with known primary malignancy and were excluded; 43 PET/CT scans were performed for patients without known primary malignancy and were included. Thirty-three (77%) had a positive PET/CT. Among the 32 patients with malignancy, 15 (47%) suffered from lung cancer and 8 (25%) suffered from colorectal cancer. The sensitivity (97%), specificity (82%), positive predictive value (94%), negative predictive value (90%), and accuracy (93%) were calculated. Thirty (91%) patients had resultant change in management. The mean CEA level for patients with malignancy (46.1 ng/ml) was significantly higher than those without malignancy (3.82 ng/ml) (P < 0.05). In predicting the presence of malignancy, a CEA cutoff at 7.55 ng/ml will achieve a sensitivity of 91% and a specificity of 73%.

Conclusion:: PET/CT, in our study population, appears to be sensitive, specific, and accurate in investigating patients with elevated CEA and without known primary malignancy. In addition to diagnosis of underlying primary malignancy, PET/CT also reveals occult metastases which would affect patient treatment options. Its role in investigating patients with elevated CEA and without known primary, compared with other investigation modalities, remains to be studied.

No MeSH data available.


Related in: MedlinePlus

A 73-year-old man presenting with elevated CEA of 46 ng/ml. Fusion PET/CT images show diffuse homogenous hypermetabolic activity along the entire axial skeleton. No definite destructive lesion was identified on CT. Findings were interpreted as marrow hyperplasia due to chronic anemia. However, subsequent blood test revealed hyperparaproteinemia and bone marrow biopsy revealed plasma cell myeloma
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Figure 4: A 73-year-old man presenting with elevated CEA of 46 ng/ml. Fusion PET/CT images show diffuse homogenous hypermetabolic activity along the entire axial skeleton. No definite destructive lesion was identified on CT. Findings were interpreted as marrow hyperplasia due to chronic anemia. However, subsequent blood test revealed hyperparaproteinemia and bone marrow biopsy revealed plasma cell myeloma

Mentions: There was 1 false-negative PET/CT in which the scan showed hypermetabolic hilar nodes and increased FDG activity in the axial skeleton [Figure 4]. The patient had known history of chronic anemia. The marrow activity appeared mildly hypermetabolic (SUVmax less than 2.5) and homogenous. Such finding was, therefore, interpreted as marrow hyperplasia. Skeletal survey was also negative. However, subsequent blood test showed hyperparaproteinemia and bone marrow biopsy revealed plasma cell myeloma. There were two false-positive PET/CT scans. The first showed mildly hypermetabolic (SUVmax: 2.0) wall thickening (wall thickness: 1.6 cm) of the urinary bladder, suspicious of bladder cancer. A flexible cystoscopy showed cystitis only and bladder biopsy was also negative for malignancy. The second one found increased FDG activity at the anus (SUVmax: 3.9) with hypermetabolic hilar and mediastinal nodes (SUVmax: 3.1–3.3) and small (1 cm) bilateral lung nodules (SUVmax: 3.8). Anal cancer with lung metastases was suspected. However, colonoscopy and MRI pelvis performed subsequently showed no suspicious anal lesion and the patient remained well on follow-up.


Efficacy of 18F-FDG PET/CT in investigation of elevated CEA without known primary malignancy
A 73-year-old man presenting with elevated CEA of 46 ng/ml. Fusion PET/CT images show diffuse homogenous hypermetabolic activity along the entire axial skeleton. No definite destructive lesion was identified on CT. Findings were interpreted as marrow hyperplasia due to chronic anemia. However, subsequent blood test revealed hyperparaproteinemia and bone marrow biopsy revealed plasma cell myeloma
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036343&req=5

Figure 4: A 73-year-old man presenting with elevated CEA of 46 ng/ml. Fusion PET/CT images show diffuse homogenous hypermetabolic activity along the entire axial skeleton. No definite destructive lesion was identified on CT. Findings were interpreted as marrow hyperplasia due to chronic anemia. However, subsequent blood test revealed hyperparaproteinemia and bone marrow biopsy revealed plasma cell myeloma
Mentions: There was 1 false-negative PET/CT in which the scan showed hypermetabolic hilar nodes and increased FDG activity in the axial skeleton [Figure 4]. The patient had known history of chronic anemia. The marrow activity appeared mildly hypermetabolic (SUVmax less than 2.5) and homogenous. Such finding was, therefore, interpreted as marrow hyperplasia. Skeletal survey was also negative. However, subsequent blood test showed hyperparaproteinemia and bone marrow biopsy revealed plasma cell myeloma. There were two false-positive PET/CT scans. The first showed mildly hypermetabolic (SUVmax: 2.0) wall thickening (wall thickness: 1.6 cm) of the urinary bladder, suspicious of bladder cancer. A flexible cystoscopy showed cystitis only and bladder biopsy was also negative for malignancy. The second one found increased FDG activity at the anus (SUVmax: 3.9) with hypermetabolic hilar and mediastinal nodes (SUVmax: 3.1–3.3) and small (1 cm) bilateral lung nodules (SUVmax: 3.8). Anal cancer with lung metastases was suspected. However, colonoscopy and MRI pelvis performed subsequently showed no suspicious anal lesion and the patient remained well on follow-up.

View Article: PubMed Central - PubMed

ABSTRACT

Aim:: To evaluate the efficacy of 18flurodeoxyglucose positron emission tomography/computer tomography (18F-FDG PET/CT) in investigating patients with elevated carcinoembryonic antigen (CEA) and without known primary malignancy, and the impact of PET/CT findings on patient management.

Setting and design:: PET/CT scans done in a tertiary hospital between December 2007 and February 2012 for elevated CEA in patients without known primary malignancy were retrospectively reviewed.

Materials and methods:: The PET/CT findings, patients' clinical information, level of CEA, histological diagnosis, and subsequent management were retrieved by the electronic patient record for analysis.

Statistical analysis:: Data were analyzed using SPSS version 19.

Results:: One hundred and one PET/CT scans were performed for patients with elevated CEA. Fifty-eight of these were performed for patients with known primary malignancy and were excluded; 43 PET/CT scans were performed for patients without known primary malignancy and were included. Thirty-three (77%) had a positive PET/CT. Among the 32 patients with malignancy, 15 (47%) suffered from lung cancer and 8 (25%) suffered from colorectal cancer. The sensitivity (97%), specificity (82%), positive predictive value (94%), negative predictive value (90%), and accuracy (93%) were calculated. Thirty (91%) patients had resultant change in management. The mean CEA level for patients with malignancy (46.1 ng/ml) was significantly higher than those without malignancy (3.82 ng/ml) (P < 0.05). In predicting the presence of malignancy, a CEA cutoff at 7.55 ng/ml will achieve a sensitivity of 91% and a specificity of 73%.

Conclusion:: PET/CT, in our study population, appears to be sensitive, specific, and accurate in investigating patients with elevated CEA and without known primary malignancy. In addition to diagnosis of underlying primary malignancy, PET/CT also reveals occult metastases which would affect patient treatment options. Its role in investigating patients with elevated CEA and without known primary, compared with other investigation modalities, remains to be studied.

No MeSH data available.


Related in: MedlinePlus