FDG-PET/CT and MRI for Evaluation of Pathologic Response to Neoadjuvant Chemotherapy in Patients With Breast Cancer: A Meta-Analysis of Diagnostic Accuracy Studies.

INTRODUCTION: This study compared the diagnostic test accuracy of magnetic resonance imaging (MRI) with that of (18)F-fluoro-2-glucose-positron emission tomography/computed tomography (FDG-PET/CT) imaging in assessment of response to neoadjuvant chemotherapy (NAC) in breast cancer. METHODS: A systematic search was performed in PubMed and EMBASE (last updated in June 2015). Studies investigating the performance of MRI and FDG-PET or FDG-PET/CT imaging during or after completion of NAC in patients with histologically proven breast cancer were eligible for inclusion. We considered only studies reporting a direct comparison between these imaging modalities to establish precise summary estimates in the same setting of patients. Pathologic response was considered as the reference standard. Two authors independently screened and selected studies that met the inclusion criteria and extracted the data. RESULTS: A total of 10 studies were included. The pooled estimates of sensitivity and specificity across all included studies were 0.71 and 0.77 for FDG-PET/CT (n = 535) and 0.88 and 0.55 for MRI (n = 492), respectively. Studies were subgrouped according to the time of therapy assessment. In the intra-NAC setting, FDG-PET/CT imaging outperformed MRI with fairly similar pooled sensitivity (0.91 vs. 0.89) and higher specificity (0.69 vs. 0.42). However, MRI appeared to have higher diagnostic accuracy than FDG-PET/CT imaging when performed after the completion of NAC, with significantly higher sensitivity (0.88 vs. 0.57). CONCLUSION: Analysis of the available studies of patients with breast cancer indicates that the timing of imaging for NAC-response assessment exerts a major influence on the estimates of diagnostic accuracy. FDG-PET/CT imaging outperformed MRI in intra-NAC assessment, whereas the overall performance of MRI was higher after completion of NAC, before surgery. IMPLICATIONS FOR PRACTICE: The timing of therapy assessment imaging exerts a major influence on overall estimates of diagnostic accuracy. (18)F-fluoro-2-glucose-positron emission tomography (FDG-PET)/computed tomography (CT) imaging outperformed magnetic resonance imaging (MRI) in intra-neoadjuvant chemotherapy assessment with fairly similar pooled sensitivity and higher specificity. However, MRI appeared to be more accurate than FDG-PET/CT in predicting pathologic response when used in the post-therapy setting.

Value of fourth and subsequent post-therapy follow-up 18F-FDG PET/CT scans in patients with breast cancer.

OBJECTIVE: To evaluate the accuracy and value of the fourth and subsequent post-therapy follow-up fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) scans in the clinical assessment of breast cancer patients. MATERIALS AND METHODS: Ninety-two female patients, with a total of 426 fourth and subsequent follow-up PET/CT scans, were retrospectively included. Patients were followed for a median of 23.7 months (range, 0.7-124.4) from the fourth follow-up PET/CT. The diagnostic accuracy of PET/CT, its impact on clinical assessment, patients' management, and survival outcome were established. RESULT: Of the 426 follow-up PET/CT scans, 264 (62%) were interpreted as positive and 162 (38%) were interpreted as negative. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the fourth and subsequent follow-up PET/CT scans were 97.7, 98.1, 98.8, 96.3, and 97.9%, respectively. Fourth and subsequent follow-up PET/CT were useful in excluding a tumor in 13.4% (39/292) of patients with a clinical suspicion of recurrence and identifying suspected recurrence in 10.5% (14/134) of patients without previous clinical suspicion. A change in management was noted in 6.7% (9/134) of scan times when the scans were performed without previous clinical suspicion of recurrence or therapy response and was 27.7% (81/292) when the scans were performed with clinical suspicion. Overall survival differed significantly between patients with all negative follow-up scans (n=23) and those who had at least one positive follow-up scan (n=69) (hazard ratio of 4.65, P<0.001). CONCLUSION: The fourth and subsequent PET/CT scans performed after the completion of primary treatment led to a change in management in 27.7% of patients when the scans were performed with clinical suspicion and only in 6.7% of patients when performed without clinical suspicion or context.

The value of fourth and subsequent post-treatment 18F-FDG PET/CT scans in the management of patients with non-Hodgkin's lymphoma.

OBJECTIVE: To evaluate the impact of fourth and subsequent follow-up PET/computed tomography (PET/CT) scans in patients with non-Hodgkins lymphoma (NHL). MATERIALS AND METHODS: This retrospective study evaluated all biopsy-proven NHL patients who had more than three follow-up scans after completion of primary treatment from 2000 to 2013 at our academic center. Among 586 patients with NHL who had at least one fluorine-18 fluorodeoxyglucose (F-FDG) PET/CT scan at our institution, a total of 77 patients with 208 fourth and subsequent follow-up F-FDG PET/CT scans, were included in the study. The impact of these follow-up scans on the clinical assessment and the management of the patients was evaluated. RESULTS: Among 208 fourth and subsequent follow-up scans, 33 were performed with a previous clinical suspicion of recurrence and 175 were performed without a previous clinical suspicion of recurrence. Fourth and subsequent follow-up PET/CT results were useful in excluding tumor in 27.3% of scan times when there was a clinical suspicion of recurrence and in identifying recurrence in 5.1% of scan times when there was no previous clinical suspicion of recurrence. Clinicians changed management after 36.4% (12/33) scans that were performed with previous clinical suspicion of recurrence and 9.2% (16/175) scans that were performed without previous clinical suspicion (P=0.001). CONCLUSION: Fourth and subsequent follow-up PET/CT scans affect the treatment and management of patients with NHL and add value to clinical assessment and management, especially in patients with a previous clinical suspicion of recurrence.