Role of scintigraphy with technetium-99m depreotide in the diagnosis and management of patients with suspected lung cancer.
BACKGROUND
In Sweden, there are over 3000 new lung cancer cases every year. There are still numerous patients with undetermined lesions after routine diagnostic evaluation by clinical examination, chest radiography, computed tomography (CT) of the thorax, and bronchoscopy. An appropriate method for further diagnostic workup is therefore needed.


OBJECTIVE
To evaluate the diagnostic value of the somatostatin analogue depreotide in patients with suspected lung cancer, and to determine in which clinical settings it would be beneficial to use 99mTc-depreotide scintigraphy.


METHODS
We included 99 consecutive patients referred to our hospital with suspected lung cancer. A clinical examination, bronchoscopy, chest radiography, CT of the thorax and upper abdomen, and scintigraphy were done. Scintigraphy was performed after injection of 740 MBq (99m)Tc depreotide with tomographical imaging of the thorax and whole-body scanning. The diagnostic outcome of the scintigrams was compared to CT, using morphology or clinical outcome as the endpoint.


RESULTS
99mTc-depreotide uptake was found in 62 out of 66 malignancies, including 57 of 58 primary lung cancer cases. Two cases of lung metastasis (one from a colon cancer and one from an adenoid cystic carcinoma originating in the palate) and one rib chondrosarcoma did not show depreotide uptake. There were 33 patients with benign lesions, of whom 16 displayed false-positive 99mTc-depreotide uptake, whereof 11 were pneumonias. Tc-99m-depreotide uptake was absent in 17 patients with benign lesions, including all 10 hamartomas. The sensitivity in detecting malignancy was 94%, and in detecting lung cancer 98%. The specificity was calculated based on two sets of data. When all cases were used, the specificity was 52%. If the 12 pneumonias are excluded, the specificity was 77%.


CONCLUSIONS
99mTc-depreotide scintigraphy has a high sensitivity in detecting lung cancer. The method is useful in decision-making with respect to surgery.
Axelsson
R
R
Division of Radiology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institute, Stockholm, Sweden. rimma.axelsson@ki.se
Herlin
G
G
Bååth
M
M
Aspelin
P
P
Kölbeck
K G
KG
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006222:Hamartoma / Q000175:diagnosis*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008168:Lung / Q000000981:diagnostic imaging*; D008175:Lung Neoplasms / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015609:Organotechnetium Compounds; D011014:Pneumonia / Q000175:diagnosis; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013004:Somatostatin / Q000031:analogs & derivatives*; D014057:Tomography, X-Ray Computed / Q000379:methods
D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D013004:Somatostatin; C444119:technetium Tc 99m depreotide