Among all summarized data, FDG-PET or PET/CT studies facilitated localization of persistent or unusual sites of metabolically active disease, enabled distinction of false-positive lesions on conventional studies related to areas of necrotic or hemorrhagic tissue, and identified additional or occult lesions in a small number of patients. Small lesion size, paucity of FDG-avid cells, and poorly differentiated tumors may contribute to false-negative studies. Variant 3: Surveillance of GTN, including refractory, relapsed, or quiescent GTN. GTN is highly chemosensitive and associated with excellent outcomes, but drug resistance and relapse can occur. This is more common in patients with high-volume disease at diagnosis or in those with inadequate initial therapy. Up to 12.5% of patients with high-risk disease will develop recurrence after initial remission [19]. Gestational Trophoblastic Disease US Pelvis Transabdominal Transvaginal US has improved sensitivity and specificity in the diagnosis of uterine masses when compared with transabdominal US, although given the rarity of this disorder, series that compare both modalities in patients with GTN are lacking [32]. Radiography Chest Evaluation of lung metastases in patients with relapsed or refractory disease is better accomplished with chest CT because primary prognostic scoring is no longer an issue in this patient population. CT Chest Because GTN metastases involve the lungs rather than the mediastinum, IV contrast enhancement is not necessary to improve lesion detection. Although radiographic evidence of tumor regression can lag behind a favorable biochemical response to treatment, thoracotomy with wedge resection of pulmonary lesions is sometimes performed in patients with persistent nodules. This is generally only indicated with isolated chemoresistant lesions in the absence of disease elsewhere [16,71]. Regardless, it remains the most common surgical procedure for extrauterine metastases [16,18,71].
Gestational Trophoblastic Disease. Among all summarized data, FDG-PET or PET/CT studies facilitated localization of persistent or unusual sites of metabolically active disease, enabled distinction of false-positive lesions on conventional studies related to areas of necrotic or hemorrhagic tissue, and identified additional or occult lesions in a small number of patients. Small lesion size, paucity of FDG-avid cells, and poorly differentiated tumors may contribute to false-negative studies. Variant 3: Surveillance of GTN, including refractory, relapsed, or quiescent GTN. GTN is highly chemosensitive and associated with excellent outcomes, but drug resistance and relapse can occur. This is more common in patients with high-volume disease at diagnosis or in those with inadequate initial therapy. Up to 12.5% of patients with high-risk disease will develop recurrence after initial remission [19]. Gestational Trophoblastic Disease US Pelvis Transabdominal Transvaginal US has improved sensitivity and specificity in the diagnosis of uterine masses when compared with transabdominal US, although given the rarity of this disorder, series that compare both modalities in patients with GTN are lacking [32]. Radiography Chest Evaluation of lung metastases in patients with relapsed or refractory disease is better accomplished with chest CT because primary prognostic scoring is no longer an issue in this patient population. CT Chest Because GTN metastases involve the lungs rather than the mediastinum, IV contrast enhancement is not necessary to improve lesion detection. Although radiographic evidence of tumor regression can lag behind a favorable biochemical response to treatment, thoracotomy with wedge resection of pulmonary lesions is sometimes performed in patients with persistent nodules. This is generally only indicated with isolated chemoresistant lesions in the absence of disease elsewhere [16,71]. Regardless, it remains the most common surgical procedure for extrauterine metastases [16,18,71].