Yildirim, Nilgun; Simsek, Melih; Aldemir, Mehmet Naci; Bilici, Mehmet; Tekin, Salim Basol

Objective: We investigated the relationship between the maximum standardized uptake value (SUVmax) of whole-body positron emission tomography/computed tomography (PET/CT) performed before treatment and the demographical and histopathological features in locally advanced breast cancer (LABC), as well as the role of PET/CT in the evaluation of pathological complete response (pCR) after neoadjuvant chemotherapy (NAC). Materials and Methods: Fifty-one LABC patients who received NAC in our center between 2011 and 2015 were retrospectively analyzed. Basal PET/CT was performed in all the patients before NAC. The SUVmax levels and demographical and histopathological results were compared. The relationship between the SUVmax values after NAC and pathological responses were evaluated. Results: The mean age of the patients was 49 (32-69) years. PET/CT performed after NAC showed complete response in 20 patients (39.2%), partial response in 28 patients (54.9%), stable disease in 2 patients (3.9%), and progressive disease in 1 patient (2%). There was no significant difference between the mean SUVmax values of the patients according to age (>50 and ≤50 years), menopausal status, tumor localization, clinical stage, and grade. The mean SUVmax value was higher in the triple-negative group than those in the HER2 positive and luminal groups. There was a significant difference in the SUVmax values between the group that achieved pCR after NAC and the group that could not achieve pCR (SUVmax value for breast 2.92 vs. 0.30; p=0.01; SUVmax value for axilla 1.5 vs. 0.0, p=0.02). Conclusion: The SUVmax values are independent of demographical features. There was a significant relationship between the pCR and SUVmax values after NAC. PET/CT could be useful in the evaluation of patients to predict the biological characteristics of tumors.

Yildirim, Nilgün; Şimşek, Melih; Aldemir, Mehmet Naci; Bilici, Mehmet; Başol Tekin, Salim

Objective Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumor of the gastrointestinal (GI) tract. The aim of this retrospective study was to explore the characteristics, prognostic factors, and treatment results of GIST cases. Methods Clinical and pathological data of 35 GIST patients at our center between 2002 and 2015 were reviewed. Results Total of 18 (51.4%) were women and 17 (48.6%) were men, with median age of 54 years. Common site of tumor was stomach (48.6%). Abdominal pain (37.1%) was common clinical symptom. Risk group distribution was 8.6% low, 31.4% intermediate, and 60% high-risk cases. Mean follow-up period of the patients was 34 months. Low-risk GIST can be treated with surgery alone. Recurrence was observed in only 1 of 10 patients who received adjuvant treatment. All 6 patients in whom metastasis was determined were in high-risk group, and 4 of them had liver metastasis. Metastasis was not detected in any of the patients who had <5 mitoses per 50 high-power field (HPF), but in 5 of 12 patients who had >10 mitoses per 50 HPF, metastasis was determined. Metastasis did not correlate with site or size of tumor, but was related to high mitotic rate (p=0.015). Median overall survival of the patients was 79 months. Conclusion Low-risk GIST can be treated with surgery alone. Imatinib therapy significantly improves survival of high-risk or advanced-stage GIST patients. Metastasis did not correlate with site or size of tumor, but correlation with high mitotic rate was observed.