Evaluation of the Internal Mammary Lymph Nodes by FDG-PET in Locally Advanced Breast Cancer (LABC)

Abstract

The presence of internal mammary (IM) lymph node metastases in breast cancer predicts outcome and may alter treatment. Standard imaging has limited usefulness for evaluation of the IM chain because of low sensitivity. Our preliminary studies suggested that [F-18]-2-fluoro-d-glucose positron emission tomography (FDG-PET) improves the detection of IM and mediastinal metastases. We therefore performed a retrospective review of women who underwent FDG-PET prior to treatment to determine the benefit of PET for imaging IM disease. The records of 28 consecutive patients undergoing FDG-PET prior to neoadjuvant chemotherapy for suspected locally advanced breast cancer (LABC) were reviewed. The presence of abnormal IM uptake on FDG-PET was noted. IM uptake on FDG PET was compared with standard radiographic imaging and was correlated with putative risk factors for IM involvement and with clinical patterns of failure. Patients did not undergo IM biopsy; however, patterns of failure were assessed to validate the FDG-PET findings. Clearly abnormal FDG uptake in the IM nodes was seen in 7 of 28 women (25%). Prospective conventional chest imaging failed to identify IM metastases in any patient. IM uptake on PET was associated with large size of the primary tumor (P = 0.03) and with inflammatory disease (P = 0.04). The presence of IM FDG uptake predicted failure by a pattern consistent with spread from IM lymph node metastasis. FDG-PET appears to be a useful noninvasive modality to detect IM metastases in LABC. Pathologic verification in a prospective study is necessary to confirm these findings.

The Role of Radiotracer Imaging in the Diagnosis and Management of Patients with Breast Cancer: Part 1—Overview, Detection, and Staging

“…18 F-FDG uptake in the IM node has been reported in some of the studies that have focused on detection of primary or axillary staging, showing IM nodal uptake as high as 25% (94). Moreover, some reports have suggested that IM 18 F-FDG uptake predicts treatment failure patterns of disease consistent with IM nodal involvement and progression (95). Tran et al showed that the likelihood of an extraaxillary lymph node finding on 18 F-FDG PET was affected by the position of the tumor (medial vs. lateral).…”

“…Several studies showed detection rates of confirmed metastatic disease in LABC at diagnosis ranging from 8% to 14% (119)(120)(121). 18 F-FDG PET is particularly helpful in detecting IM and mediastinal nodal metastases (95,122). These are common sites for metastatic involvement in LABC and are not optimally evaluated with conventional imaging alone.…”

Role of FDG PET-CT in evaluation of locoregional nodal disease for initial staging of breast cancer

“…Prognosis of patients with both axillary and IMN metastases is poor when compared with axillary nodal metastasis only [29] . IMN involvement might predict treatment failure, early recurrence or distant metastasis in breast cancer [30] . Multiple studies have consistently found that medial breast cancers carry a worse prognosis compared with lateral cancer, even after adjusting for other known prognostic factors.…”

Should FDG PET/CT be used for the initial staging of breast cancer?

“…Depicting lymph node involvement in levels or basins other than those addressed by routine ALND may have major impact on treatment strategies. Many studies suggest that FDG PET performs better than conventional imaging in depicting involvement in high-level axillary (Berg level III) as well as in supraclavicular and internal mammary lymph nodes [8,9,[13][14][15]. PET/CT is particularly appealing compared to PET alone as it provides the precise location of involved nodes [7][8][9].…”