The role of 18F-FDG PET/CT in detecting synchronous regional and distant metastatic disease in patients with an in-breast tumour recurrence.

Abstract

Background: In line with the trend towards minimally invasive, patient-tailored treatment, a selected group of patients with an in-breast tumour recurrence (IBTR) is treated by repeat breast-conserving treatment (BCT). To select eligible patients for repeat BCT, a reliable pre-operative work-up is essential. This study reports on the role of ¹⁸F-FDG PET/CT in detecting synchronous regional and distant metastases in patients with IBTR.

Patients and methods: A nation-wide data query was sent out to all Dutch hospitals offering breast cancer treatment. Breast cancer surgeons from 34 hospitals participated, filling electronic case report forms (eCRFs) on 549 patients treated for IBTR from 2016 to 2017.

Results: Of the 549 included patients, 297 were screened using ¹⁸F-FDG PET/CT for the presence of distant metastases. Forty of them (13.5 %) presented with synchronous distant metastatic disease. In 168 clinically node-negative patients who underwent ¹⁸F-FDG PET/CT, a suspect regional lymph node was found in 18 (10.7 %). Final pathology of these lymph nodes yielded a positive lymph node in 12 patients (7.1 %). Positive predictive value (PPV) of ¹⁸F-FDG PET/CT in clinically node-negative patients was 66.7 % and negative predictive value (NPV) was 85.3 %.

Conclusion: The clinically relevant percentage of synchronous distant metastatic disease justifies the use of ¹⁸F-FDG PET/CT in the workup of patients with an IBTR. Furthermore, ¹⁸F-FDG PET/CT can assist in detecting regional axillary lymph node metastases, but requires histopathological confirmation given the moderate PPV, before clinical decisions can be made.