J Nucl Med. 2007; 48 (Supplement 2):270P
General Clinical Specialties: Endocrinology
Endocrinology Posters |
FDG-PET imaging as a potential indicator of systemic immune response to thyroid cancer
Gonca Bural1,
Gunsel Acikgoz1,
Mohamed Houseni1,
Simin Dadparvar1,
Wichana Chamroonrat1 and
Abass Alavi1
1 Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
1223
Objectives: Liver, spleen and bone marrow represent the organs with high reticuloendothelial system (RES) activity. This system is composed of cells which play an active role in the defense mechanism in the removal of dying cells, cell debris and malignant cells. We hypothesized that in patients with active malignancy,metabolic activity of organs containing RES will be higher than patients with no evidence of active tumor. Methods: We included two groups of patients with thyroid cancer who had undergone FDG PET scans for clinical purposes. First group consisted of 24 patients (11 males, 13 females; mean age 45.5± 16.8 years) with the initial diagnosis of thyroid cancer that did not have evidence of active disease at the time of examination based on various tests including FDG PET scan. The second group consisted of 32 patients (13 males, 19 females; mean age 56.3±15.3 years) with known active primary residual or metastatic thyroid cancer. The mean and maximum SUV for the liver, spleen, bone marrow, heart and for the lung were measured. We compared the SUVs for each organ noted above for the two groups. Results: The maximum SUV and SD values for liver, spleen and bone marrow were; 2.95±0.7, 2.15±0.6, 2.05±0.3 respectively in the group with active disease. The values were 2.5±0.6, 1.79±0.4, 1.66±0.4 respectively for the group with no active disease.The mean and maximum SUVs for the liver, bone marrow and spleen were higher in patients with evidence of active residual and or metastatic thyroid cancer compared to patients without evidence of active malignancy (p< 0.05). In contrast, the mean and maximum SUVs for heart and lung did not show any significant difference between the two groups (p>0.05). Conclusions: The maximum and mean SUV for the organs with RES activity were higher in patients with active thyroid cancer with or without metastasis than in patients without any evidence of active thyroid cancer. This could imply that organs with RES cells play an important role in the immune response which can be detected and quantified by the FDG-PET imaging technique. The degree of this response may have a prognostic role in such patients and should be explored further in the future.
