Endocrine Abstracts

Adrenocortical carcinoma (ACC) is a rare tumour characterised by a high rate of recurrence following radical surgery. Surgery of recurrent ACC may increase survival; thus, it is mandatory a timely and accurate detection of recurrence, either to increase the chance of radical extirpation or to avoid unnecessary surgery. This study investigated the role of PET–CT in the diagnosis of recurrence of ACC during follow-up of disease-free patients and analyzed whether this tool may improve the therapeutic strategy. A retrospective evaluation of the use of PET–CT was done in ACC patients with suspected recurrence at CT imaging during their follow-up. Data of 57 patients followed at our center were retrieved. Recurrence was confirmed by pathology when lesions were removed (23 cases), or fine-needle biopsy (five cases), or detection of unequivocal tumour progression during follow-up (29 cases). CT scan of the 57 patients showed a total of 153 lesions while PET–CT showed at least one focal uptake in 40 patients (70.2%) for a total of 99 lesions. For liver lesions, PET–CT showed a significantly higher specificity and a reduced sensitivity (sensitivity, CT 80% vs PET 50%, P=0.046 and specificity, CT 89% vs PET 99%, P=0.057). With regard to local recurrence, the two tests had similar diagnostic accuracy (sensitivity: CT 87% vs PET 79%, P=NS and specificity: CT 94% vs PET 94%, P=NS). The same considerations apply to abdominal recurrences (sensitivity: CT 76% vs PET 70%, P=NS and specificity: CT 94% vs PET 99%, P=NS) and bone, in which CT and PET have equal sensitivity (86%) and specificity (98%). Conversely, in the lungs CT scan had non-significantly better diagnostic accuracy (sensitivity: CT 87% vs PET 53%, P=NS and specificity: CT 91% vs PET 95%, P=NS). In 18 patients (33%), PET findings changed the therapeutic strategy that was planned after CT as to the possibility of a radical surgery. In conclusion, PET can be considered an useful adjunct to CT for the diagnosis of ACC recurrence, increasing diagnostic specificity for suspected liver or abdominal recurrences, and improving the identification of occult lesions or multiple tumour sites. Use of PET has important clinical implications, allowing a smarter use of surgery due to improved selection of patients who can be radically resected.