Application of Positron Emission Tomography (PET) in Postoperative Follow-Up of the Breast Cancer

ABSTRACT

PURPOSE: Positron Emission Tomography (PET) is an imaging method that can diagnose diseases by detecting physiologic and biochemical changes of the body. In this study, we attempted to evaluate the value of PET in the postoperative follow-up of breast cancer. METHODS: From September, 1994 to December, 2001, postoperative PET was performed 67 times at Samsung Medical Center on 66 patients who underwent curative operation for breast cancer. Clinical outcomes were confirmed by clinicoradiologic courses, fine needle aspiration cytology, biopsy and operation. We reviewed the medical records and PET reports of these patients. RESULTS: The time interval between operation and PET ranged from 1 to 88 months with a median of 26.5 months. The PET results were abnormal physical examination (23 cases, 34.3%), equivocal result of bone scan (22 cases, 2.8%), other radiologic abnormalities (9 cases, 13.4%), abnormal laboratory findings (4 cases, 6.0%), and symptoms of patients (4 cases, 6.0%). Among the 67 PET studies, 48 were confirmed as having metastasis or recurrence, while 19 did not have metastasis or recurrence. Forty-five of the studies produced true positive results, 16 true negative, 3 false positive and 3 false negative. Therefore, in the detection of postoperative metastasis or recurrence of breast cancer the parameters for the use of PET were 93.8% sensitivity, 84.3% specificity, 93.8% positive predictive value, 84.3% negative predictive value and 91.0% accuracy. On the basis of the lesion site, the accuracy of PET in the detection of bone (98.5%), lung (100%) and liver (98.5%) metastases was superior to that of local recurrence (85.1%) or lymph node metastasis (86.6%). CONCLUSION: PET may be diagnostically helpful in a select subgroup of patients for whom findings remain inconclusive after performning conventional postoperative follow-up methods for breast cancer, especially in the detection of bone, lung and liver metastases.