Diagnosis of Breast Cancer Metastases with PET/TC in Patients with Elevation of Tumor Markers: Final Data

ABSTRACT Background Breast cancer is one of the most common cancers worldwide. PET / CT is more accurate than traditional methods for the detection of distant metastases or local recurrence and enables for early assessment of treatment response in patients after surgery for breast cancer undergoing primary chemotherapy. PET/CT is not considered a conventional examination during follow-up of patients with breast cancer, but recent data indicate its usefulness both in cases of asymptomatic increase of tumor markers that uncertain conventional imaging results. This study investigates the potential role of PET / CT to detect clinically occult metastases in patients with suspected recurrence of breast cancer during follow-up. Methods The authors studied 67 patients in breast cancer follow-up after primary surgery and chemotherapy and/or external radiotherapy. All patients were in remission without any other clinical or instrumental signs of relapses, except for the progressive elevation of CA 15.3 and/or CEA, tested during the follow-up. In 47 patients conventional imaging provided uncertain results and increase of CA 15.3 that was not correlated to any evidence of metastatic disease. The final diagnosis was obtained by histopathology (n.13) or by combined follow-up (n.54), including imaging at least 6 months later. Results Disease relapse was proven in 55 out of 67 patients and successfully PET/CT has identified clinically occult disease with an excellent sensitivity. In 21 cases the anatomical distribution of metastasis sites was in the bone, 16 in the lymphonode, 11 in the lung and 7 in the liver. We found 2 false-negative, 4 false-positive and 6 true-negative. Conclusions PET/TC may be more sensitive than the serum tumor markers in detecting relapse of breast cancer. This study demonstrated the clinical utility of tumor marker-guided PET in the follow-up of breast cancer patients. Disclosure All authors have declared no conflicts of interest.