Preoperative staging of large primary breast cancer with [18F] fluorodeoxyglucose positron emission tomography/computed tomography compared with conventional imaging procedures

Purpose To evaluate the utility of positron emission tomography (PET) and [F-18] fluorodeoxyglucose in the initial staging of large primary breast tumors. Patients and Methods This prospective study was approved by the ethics committee, and all patients gave their informed consent before enrollment. Sixty consecutive patients with large (> 3 cm) primary breast cancer diagnosed by clinical examination and breast magnetic resonance imaging (MRI) were entered onto the study. The mean age was 57 +/- 13 years. Chest computed tomography (CT), liver ultrasonography, bone scan, and PET/CT were performed in all patients. All findings were histologically confirmed, and/or at least 1 year of follow-up was required. Correlation between parameters was calculated using Pearson's correlation coefficient. P <.05 was considered statistically significant. Results Primary tumor was identified by both PET/CT and MRI in all patients. Multifocal and/or multicentric tumors were found in 19 patients by MRI. Axillary lymph node metastases were found in 20 of 52 patients. Extra-axillary metastatic lymph nodes were also found in three patients. One patient showed an infiltrated lymph node in the contralateral axilla. The sensitivity and specificity for PET/CT to detect axillary lymph nodes metastases were 70% and 100%, respectively. PET/CT diagnosed all extra-axillary lymph nodes. The overall sensitivity and specificity of PET/CT in detecting distant metastases were 100% and 98%, respectively; whereas the sensitivity and specificity of conventional imaging were 60% and 83%, respectively. PET led to a change in the initial staging in 42% of patients. Conclusion PET/CT underestimates locoregional lymph node staging in large primary breast cancer patients. PET/CT is a valuable tool to discard unsuspected extra-axillary lymph nodes and distant metastases.