Conflicting or complementary role of computed tomography (CT) and positron emission tomography (PET)/CT in the assessment of thymic cancer and thymoma: our experience and literature review.
BACKGROUND
To evaluate the role of computed tomography (CT) and positron emission tomography (PET)/CT in patients with thymic cancer and thymoma at initial staging.


METHODS
We retrospectively reviewed CT and PET/CT scans of 26 patients with a thymic cancer (n = 9) or thymoma (n = 17). Chest CT findings documented were qualitative and quantitative. Both qualitative and semiquantitative data were recovered by PET/CT. The comparisons among histological entities, outcome, and qualitative data from CT and PET/CT were made by non-parametric analysis.


RESULTS
PET/CT resulted positive in 15/17 patients with thymoma. CT was available in 5/9 (56%) patients with thymic cancer and in 3/17 with thymoma. All quantitative CT parameters were significantly higher in patients with thymic cancer than thymoma (maximum axial diameter: 45 vs. 20 mm, maximum longitudinal diameter: 69 vs. 21 mm and volume: 77.91 vs. 4.52 mL; all P < 0.05). Conversely, only metabolic tumor volume (MTV) and total lesion glycolysis were significantly different in patients with thymic cancer than thymoma (126.53 vs. 6.03 cm3 and 246.05 vs. 20.32, respectively; both P < 0.05). After a median follow-up time of 17.45 months, four recurrences of disease occurred: three in patients with thymic cancer and one with a type B2 thymoma. CT volume in patients with recurrent disease was 102.19 mL versus a median value of 62.5 mL in six disease-free patients. MTV was higher in the recurrent than disease-free patient subset (143.3 vs. 81.13 cm(3)), although not statistically significant (P = 0.075).


CONCLUSIONS
Our preliminary results demonstrated that both morphological and metabolic volume could be useful from a diagnostic and prognostic point of view in thymic cancer and thymoma patients. A large multi-center clinical trial experience for confirming the findings of this study seems mandatory.
Oncologic Radiology Unit, Veneto Institute of Oncology IOV - IRCCS Padua, Italy.
Elena
E
Scagliori
Radiotherapy and Nuclear Medicine Unit, Veneto Institute of Oncology IOV - IRCCS Padua, Italy.
Laura
L
Evangelista
Oncologic Radiology Unit, Veneto Institute of Oncology IOV - IRCCS Padua, Italy.
Annalori
A
Panunzio
Department of Cardiac, Thoracic and Vascular Science, University of Padua Padua, Italy.
Fiorella
F
Calabrese
Department of Cardiac, Thoracic and Vascular Science, University of Padua Padua, Italy.
Nazarena
N
Nannini
Department of Radiology, Hospital of San Donà di Piave Venice, Italy.
Roberta
R
Polverosi
Oncologic Radiology Unit, Veneto Institute of Oncology IOV - IRCCS Padua, Italy.
Fabio
F
Pomerri
Computed tomography; PET/CT; prognosis; thymic cancer; thymoma