Agustina Vicente Bartulos MD, Presenter: Nothing to Disclose

Raquel Jover Diez, Abstract Co-Author: Nothing to Disclose

Cristina Gonzalez Gordaliza MD, Abstract Co-Author: Nothing to Disclose

Luis Gorospe Sarasua, Abstract Co-Author: Nothing to Disclose

Javier Garcia Poza, Abstract Co-Author: Nothing to Disclose

Daniel Lourido Garcia, Abstract Co-Author: Nothing to Disclose

Jose Romero Sanchez, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Metastatic cancer of unknown primary (CUP) origin is a syndrome consisting of a biopsy-confirmed malignancy with an unidentified primary lesion after careful review of the patient’s medical history and relevant clinical tests. Only 20–27% of primary tumors are identified by conventional radiological imaging. The aim of this study was to evaluate the potential diagnostic role of fused 18F-FDG PET-CT imaging for the detection of metastatic occult primary tumors.

The study population consisted of 61 consecutive patients collected during the last 9 months with CUP. All patients underwent a whole-body 18F-FDG PET-CT scan. The images were jointly assessed by one nuclear medicine and one radiologist physicians. Image interpretation was reached by consensus.

The patient population consisted of 61 patients (37 men), 32% had been detected lymph nodes (mainly cervical), 29% nodules or masses in different locations (for example, soft tissues masses) and 24% metastases in different organs (50% hepatic, followed by osseous and lung mets). Other findings like ascitis or pleural efusión were less frecuent. A total of 38% had squamous cell carcinoma, 30% patients had adenocarcinoma, followed poorly differentiated ca, lymphoid tumors and large cell ca. PET-CT results were negative in 11 patients, non-specific findings in 10 patients, hypermetabolic lesions suggestive of malignancy (SUVmáx >3) in 40 patients (66%). In 21 (34%) patients, the primary tumor site remained occult. In adition in 83% of the patients, PET-CT identified new lesions and changed the stage of known neoplasma.

PET/CT identified the primary tumor in 66% of patients with suspected CUP, showing a better accuracy than other imaging techniques. In our study the diagnostic accuracy of PET/CT was higher than previously described in literature (24-40%). However, the main limitation of this technique is the low ability to detect metastatic occult primary tumors in patients without macroscopic lesions.

Although CUP syndrome is characterised by a poor prognosis, detection of the primary site may be important, as it allows initiation of targeted therapy, thereby significantly improving survival

Vicente Bartulos, A, Jover Diez, R, Gonzalez Gordaliza, C, Gorospe Sarasua, L, Garcia Poza, J, Lourido Garcia, D, Romero Sanchez, J, et al, , et al, , Role of PET-CT Imaging for the Detection of Unknown Primary Tumors.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5012810.html