P1-18-02: Descriptive Analysis of the Management of Breast Cancer Patients with a Solitary Lesion Diagnosed with 18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Scan.

Abstract

Abstract Background: a small percentage of breast cancer (BC) patients (pts) will develop oligo-metastatic disease (OMD), often with a solitary lesion (SL). Growing evidences suggest a survival benefit for pts who undergo local treatment for SL. However, 18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scan might improve the detection of truly SL, an important prerequisite for local treatments. We describe pattern of presentation and management of pts with SL diagnosed by FDG-PET/CT. Patients and Methods: From a bi-institutional database we retrospectively identified 137 pts who underwent a PET/CT because of rising tumor markers (95, 69%) or clinical/radiological suspect of disease recurrence (42, 31%). Median time from surgery of primary tumor to metastatic progression was 48 months (range 6–216 months). Comparisons of categorical and continuous variables were analyzed by the Chi-Square test and Mann-Whitney U test. Significance was set at p<0.05. Results: PET/CT was positive in 78/137 pts. In 35 pts (26%) abnormal PET/CT findings consisted of a single area of increased metabolic activity, whereas in the other 43 (31%) multiple hyper-metabolic lesions were found. Twenty/35 pts with single hyper-metabolic spots had confirmed malignant SL: 17 (49%) were BC recurrences and 3 (9%) were new primary tumors other than BC. In the remaining 15 pts, hyper-metabolic SL were consistent with areas of inflammation, past trauma, thyroid struma and physiological ovarian functioning. Eight pts with SL (2: liver, 3: bone, 2: soft tissues, 1: lung) underwent local therapy, which consisted of surgical excision ± radiation therapy (4 pts), percutaneous cementoplasty and radiation therapy (2 pts), radiation therapy alone (1 pts) and percutaneous radiofrequency ablation (1 pts). After local treatment 7 pts also received systemic therapy: chemotherapy for 3 and endocrine therapy for 4 pts. Pts with solitary bone lesion also received zoledronic acid. Nine pts received only systemic therapy (4: soft tissues, 2: bone, 2: liver, 1: lung). Median age at the time of diagnosis of SL, histology of primary tumor, hormone receptor status, HER2 status, site of SL and prior exposure to adjuvant chemotherapy did not differ between pts treated with local or systemic therapy. At the time of this analysis, 11/17 pts with confirmed SL had progressed (5 had been treated with local and systemic therapy and 6 with systemic therapy alone), and all the pts were alive. Discussion: Our retrospective analysis suggests that FDG-PET/CT is a useful tool to identify BC pts with OMD susceptible of local and aggressive treatment, despite the impressive number of solitary non-neoplastic lesions. Our numbers are too small to point out any benefit from the addition of local over systemic treatment, and survival analyses were not significant. Nevertheless, due to growing evidences of a benefit of aggressive treatments for SL, treatment options for pts with OMD cannot leave aside local treatments. However, with the limitation due to small numbers and retrospective design, our data are hypothesis generating, and should be interpreted with caution. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-18-02.