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Abstract Breast cancer is the most frequently diagnosed cancer in women. It remains the second most frequent cause of cancer death after lung cancer in women worldwide. PET-CT provides the needed information about both the metabolic activity as well the anatomical location of the neoplasm combining the advantages of both CT and PET. This study evaluated 30 female patients with breast cancer, age range between 33 and 73 years with mean age 53.5 years by PET/CT to assess the breast cancer and search for metastasis and recurrence. In our study PET/CT identified the primary tumor in 10 out of 30 patients Our study showed that 25 cases were pathologically proven invasive ductal carcinoma, 3 cases invasive lobular carcinoma, 1case mucinous and 1 case anaplastic. In our study the contralateral breast affection occurred in 2 cases (2.8%) - The fused PET/CT images were analyzed and 11 patients were positive for metabolically active FDG avid axillary nodal lesions (n=11) (36.7 %), cervical lymph node affection (n=6)(20%), mediastinal lymphadenopathy (n=12) (40%) and abdominal lymph nodes affection (n=8) (26.7%). - Bone metastases occurred in 12 cases (40%) - Hepatic metastases occurred in 5 cases (16.7%) - Pulmonary metastases occurred in 11 cases (36.7%) - Other visceral metastasis occurred in 9 cases (30%). The study showed that the breast malignancy was unilateral in 28 patients (95.8%) and bilateral in 2 patients (4.2%). In our study, PET/CT detected operative bed tumor recurrence in 5/30 cases (16.7 %); being isolated operative bed recurrence after surgery in (1/20) case & mixed locoregional and distant metastases in (4/20) cases In follow up of the cases, progression occurred in 14 cases (46.7 %), stationary course in 10 cases (33.3 %) and regressive course in 6 cases (20.0 %). In our study, the sensitivity of CT alone in detection of the breast lesions in both breasts was 81.2%, and PET in combined PET-CT raised this percentage to reach 100%. The sensitivity of CT alone in detection of lymph node metastasis was calculated to be 95% and PET in combined PET-CT raise this percentage to reach 100%. The sensitivity of CT alone in detection of bone lesion deposits was calculated to be 75% and PET in combined PET-CT raise this percentage to reach 91,6%. The sensitivity of CT alone in detection of pulmonary nodule metastasis was 72.2% and PET in combined PET-CT raise this percentage to reach 100%. The sensitivity of CT alone in detection of hepatic deposits was 40% and PET in combined PET-CT raise this percentage to reach 80%.Summary 83 The sensitivity of CT alone in detection of other visceral metastasis was 55.5% and PET in combined PET-CT raise this percentage to reach 88.8%. FDG-PET-CT is generally more sensitive in the detection of distant metastases than conventional imaging, and is therefore a more accurate method of determining recurrence of the disease. FDG-PET-CT is highly useful for monitoring response to therapeutic interventions. This technique can identify response to therapy earlier than any other imaging method currently available which greatly improves patient management by allowing termination of ineffective and toxic therapies. Role of PET-CT in preoperative cases: 1- For detection: o PET CT has limited role in detecting primary breast cancer, because of its inability to demonstrate small (subcentimetric) and low-grade lesions. 2- For staging: o Evaluation of the primary tumor (T staging) e.g assessment of underlying muscle, skin and chest wall infiltration o Detection of nodal metastasis (N staging) - PET CT can’t be used in axillary staging as the modality cannot demonstrate the number of lymph nodes involved; the number is an important prognostic factor, and the nodal FDG uptake is not specific for malignancy. o Detection of distant metastasis (M staging) - The most important advantage of PET/CT compared with other imaging modalities is the capability of detecting unsuspected distant metastases during a single whole-body examination. - FDG PET/CT is likely to be more useful as a screening test for distant metastases in patients with an advanced stage of breast cancer. Role of PET-CT in postoperative cases: - PET-CT is a good modality to detect operative bed tumoral recurrence and useful to determine whether this recurrence is isolated or not. - PET/CT can detect distant metastases not visible on conventional imaging. - Fused PET/CT was highly efficient in the evaluation of skeletal metastases with superior performance in detection of early bone marrow infiltration not apparent on CT. - PET/CT has no or minimal value in the evaluation of small subcentimetric pulmonary nodules because of their lower FDG uptake, but it is considered a useful tool in the evaluation of large pulmonary nodules (> 1.0 cm). - FDG PET can detect hepatic metastases > 1cm in diameter, but it has a limited capability for detection of subcentimetric hepatic metastases. - PET/CT is poorly sensitivity to detect brain metastases due to high brain physiological FDG uptake.Summary 84 Role of PET-CT in follow up cases. - FDG-PET is useful in therapy response assessment by demonstrating decline in the tumor glucose metabolism with successful chemotherapy. - PET-CT provides quantitative evaluation of the therapy-induced changes in tumor metabolism that is helpful in making decisions about continuation, modification or cessation of therapy. Advantages of PET-CT over other modalities: - PET is more specific than MRI for characterizing and detecting breast lesions > 1 cm. - Better than bone scan in detecting lytic osseous metastases. PET is complementary to a bone scan, but it cannot replace a bone scan. PET detects some metastases that bone scan does not and vice versa. - Superior than CT alone in detecting early marrow based and healed osseous deposits. Disadvantages of PET-CT: - PET-CT is not sensitive for detecting breast lesions that are < 1 cm and low grade lesions. - Cannot replace axillary biopsy as it cannot demonstrate the number of lymph nodes which is an important prognostic factor, and the nodal uptake is not specific for malignancy. - It is not currently used as a screening modality due to its cost. - Finally, we recommend combined FDG-PET-CT as the investigation of choice for breast cancer patients, as it has superior results over equivocal findings of the conventional imaging, greatest role in detection of distant metastasis, tumor recurrence and newly developed lesions and for its greatest impact on detection of the disease progression. |