Objective: The role of baseline and post-treatment standardized uptake value (SUVmax) values in predicting pathological response in patients with breast cancer after neoadjuvant chemotherapy (NAC).Materials and Methods: Thirty patients with invasive ductal breast cancer were included in this retrospective study. F-18 fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) examinations were performed before and after NAC. Pretreatment SUVmax (SUVmax I), post-treatment SUVmax (SUVmax II) and dSUVmax values of primary breast cancer were obtained. Breast tumor pathology preparations were examined for the evaluation of tumor response according to the Miller and Payne classification. Patients were grouped as responding to treatment (pCR) and unresponsive to treatment (nonpCR). In all analyses,p<0.05 was considered statistically significant.Results: The mean age of the 30 patients included in the study was 51.2 +/- 11.98 years. In the study-defined grouping, 13 patients (43.3%) were nonresponders and 17 patients (56.7%) were responders. dSUVmax was significantly greater in the responders group compared to the nonresponders group, while SUVmax II was lower (p = 0.001 andp = 0.004, respectively). There was no significant difference between the responders and nonresponders in terms of age, tumor diameter, and SUVmax I values. Multivariate logistic regression analysis showed dSUVmax to be the only independent predictive factor for pCR.Conclusion: F-18 FDG PET/CT was an effective method in evaluating the treatment response after NAC in breast cancer, and dSUVmax and post-treatment SUVmax can be used to predict the response of the primary tumor to treatment.

Computed tomography (CT) and positron emission tomography (PET) are the most commonly used methods for diagnosis and staging in both malignant and benign diseases of the lung parenchyma and mediastinum. Endobronchial ultrasonography (EBUS) guided transbronchial needle aspiration biopsy (TBNA) has become widespread in recent years because it allows minimally invasive tissue sampling. PET-CT has high sensitivity in the diagnosis of malignancy but has low specificity. The false positive rate is high with the SUVmax 2.5 cutoff value, which is widely used in studies about malignancy. In our study, we evaluated lymph nodes with high F18-fluorodeoxyglucose (FDG) uptake on PET/CT and sampled by EBUS-TBNA. We aimed to calculate the new SUVmax cutoff values in the differentiation of malignancy. Our study included 103 patients who were examined for any reason and who underwent biopsy with EBUS-TBNA due to mediastinal or hilar lymph node enlargement on PET-CT. The relationship between PET-CT findings and EBUS findings, EBUS-TBNA results was evaluated. Biopsies were taken from 140 lymph nodes in 103 patients included in our study, and 39 (27.8%) were diagnosed as malignant. In our study, when the SUVmax cutoff value in PET-CT is taken as 2.54, the sensitivity is 98%, but the specificity remains at the level of 12%. When the SUVmax cutoff value in PET-CT was taken as 4.58, the sensitivity was 92% and the specificity was 49%. When this value was accepted as 5.25, and 6.09 the sensitivity was respectively 90% and 85%, the specificity was respectively 52% and 60%. In evaluations, we conducted in order to determine different SUVmax cutoff values that can be used for higher sensitivity and specificity in malignancy studies, the cutoff values were 4.58, 5.25, and 6.09. It is thought that these cutoff values will be useful both for diagnosing malignancy and for distinguishing benign pathologies.

We describe a rare case of metastatic pilomatrix carcinoma with distant metastases 10 months after diagnosis. A 37-year-old woman was diagnosed with pilomatrix carcinoma by excisional biopsy from the occipital region and referred to us for F-18-FDG PET/CT examinations at the time of diagnosis and 10 months after diagnosis. The first PET/CT did not show any pathological activity, whereas the second PET/CT showed multiple intensive F-18-FDG uptakes in the right lung parenchyma, right hemithorax pleura, liver, and bones.