Clinicopathological factors affected no ¹⁸FDG uptake in ¹⁸FDG-PET CT: only invasive ductal cancer.

Abstract #6007

Background: Positron emission tomography with fluorine-18 fluoro deoxy-glucgose (¹⁸FDG-PET CT) recently used is suggested more useful tool for accurate, non-invasive imaging modality of the prediction of prognosis and staging of breast cancer. The aim of this study was to evaluate whether no enhanced ¹⁸FDG uptake would be associated with the biological non-aggressiveness of invasive ductal carcinoma and suggest limitation of using ¹⁸FDG-PET CT for preoperative evaluation.
 Materials and Methods: The patients were consisted of 124 female patients raging in age from 29-80 years (average 51.1 years) with primary invasive ductal carcinoma. All patients had histologically or cytologically proven invasive ductal carcinoma before performing ¹⁸FDG-PET CT sacn. All patients were examined with ¹⁸FDG-PET CT sacn before neoadjuvant chemotherapy. Patients undergoing excisional biopsy were excluded from this study.
 Results: 20 patients had primary tumor with no enhanced ¹⁸FDG uptake and ¹⁸FDG-PET CT showed hypermetabolic axillary foci in 25 patients. In these 25 patients, two was false positive findings. Histologic examination was confirmed 56 patients had axillary lymph node metastasis. The mean tumor diameter was 2.2 cm (range 0.4-6 cm). With regard to histopathologic grading, 117 were grade 1 and 2, and 7 were grade 3. It was correlation with no enhanced ¹⁸FDG uptake (p=0.003). No enhanced ¹⁸FDG uptake in invasive ductal carcinoma depended on presence of axillary lymph node metastases (p=0.014). Small tumor (< 2.0cm) also was significantly correlated with no enhanced ¹⁸FDG uptake. The relationship between no enhanced ¹⁸FDG uptake and presence of lymphovascular invasion, necrosis and calcification was not significant. The immunohistochemical stain of ER/PR/p53/c-erbB2 did not correlate with no enhanced ¹⁸FDG uptake. Triple negative tumor also was not significant (p=0.072). 123 specimens were examined with Ki-67. Ki-67 positivity ranged from 0% to 60% (mean 15%). 67 specimens showed immunoreactivity to Ki-67 antigen in < 10% of tumor cell. This revealed a significant correlation between no enhanced ¹⁸FDG uptake and Ki-67 (p=0.003). Logistic regression analysis between these factors was shown that histologic grade, status of axillary lymph node metastases and Ki-67 were correlated with no enhanced ¹⁸FDG uptake.
 Discussion: The our results demonstrated that an association exists between no ¹⁸FDG uptake and good prognostic factors in invasive ductal cancer, such as low histologic grade (1 & 2), no axillary lymph node metastases and low Ki-67 (<10%). Although further studies are needed, ¹⁸FDG-PET CT may be suggested more useful tool for accurate, non-invasive imaging modality of the prediction of prognosis and we purpose the limitation of using ¹⁸FDG-PET CT for follow-up study in these patient.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6007.