Publications by authors named "Okan Falay"

10 Publications

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The prediction of spread through air spaces with preoperative 18F-FDG PET/CT in cases with primary lung adenocarcinoma, its effect on the decision for an adjuvant treatment and its prognostic role.

Nucl Med Commun 2021 Mar 30. Epub 2021 Mar 30.

Department of Nuclear Medicine Department of Medical Oncology Department of General Thoracic Surgery, Koç University School of Medicine Department of General Thoracic Surgery, VKF American Hospital Department of Pathology, Koç University School of Medicine, Istanbul, Turkey.

Purpose: In lung adenocarcinoma cases, 'spread through air spaces' (STAS) is a new indicator of invasion and directly related to disease survival. The aim of our study is to establish whether a preoperatively performed 18F-Fluorodeoxyglucose (FDG) PET/computed tomography (CT) imaging data can predict the presence of STAS in cases with lung adenocarcinoma and thus predict the decision for the type of surgery and adjuvant chemotherapy.

Materials And Methods: Between 2000 and 2019, we retrospectively analyzed 63 patients with lung adenocarcinoma cases that had undergone lobectomy or pneumonectomy. Semiquantitative parameters were calculated and metabolic tumor volume (MTV)/CT volume (CTV) ratio was recorded from FDG PET/CT data. The pathological samples from these patients were evaluated for STAS. All these values were evaluated for their correlation with the alveolar spread.

Results: There was no statistically significant correlation to be found between CTV, MTV, total lesion glycolysis (TLG), standardized uptake value (SUV)max, SUVmean and STAS (P > 0.05). However, MTV/CTV ratio above 1 had statistically more alveolar spread. In the group with an MTV ratio above 1, STAS positivity was 27 (75%), and 9 (25%) did not have STAS, whereas these were 6 (22.2%) patients who had STAS, and 21 (77.8%) did not have STAS in the group with below 1 (P < 0.001).

Conclusions: In the preoperative PET study inoperable lung adenocarcinoma cases, MTV/CTV ratio higher than 1 was found to predict STAS positivity. As a result, it was found that it provided significant clinical additional information regarding the need for a surgical approach (lobar resection instead of sublobar) and adjuvant chemotherapy.
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http://dx.doi.org/10.1097/MNM.0000000000001414DOI Listing
March 2021

Ga-PSMA-11 Positron Emission Tomography/Computed Tomography for Primary Lymph Node Staging Before Radical Prostatectomy: Central Review of Imaging and Comparison with Histopathology of Extended Lymphadenectomy.

Eur Urol Focus 2021 Mar 25;7(2):288-293. Epub 2021 Jan 25.

Department of Urology, Koc University Hospital, Istanbul, Turkey; Martini-Klinik Prostate Cancer Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany; Department of Urology, University Hospital Hamburg-Eppendorf, Hamburg, Germany.

Background: Results from prospective trials have shown higher accuracy of prostate-specific membrane antigen (PSMA)-based positron emission tomography (PET)/computed tomography (CT) in detection of lymph node metastasis (LNM) compared to conventional imaging.

Objective: To evaluate the accuracy of Ga-PSMA-11 PET/CT for LNM detection in patients undergoing radical prostatectomy (RP) and extended pelvic lymph node dissection (PLND).

Design, Setting, And Participants: Between June 2014 and November 2020, 96 patients with Ga-PSMA PET/CT for primary staging underwent RP and extended PLND.

Outcome Measurements And Statistical Analysis: The results from Ga-PSMA PET/CT were compared with histologic data from primary PLND in 96 patients. All Ga-PSMA PET/CT scans were centrally reviewed.

Results And Limitations: Of 96 patients, 15.6% (n = 15) harbored LNMs. The median prostate-specific antigen at Ga-PSMA PET/CT was 8.0 ng/ml (interquartile range 5.5-11.7). The majority of patients had intermediate- (52.1%) or high-risk disease (41.7%). Biopsy grade group 4 and 5 was present in 22.9% and 15.6%, respectively. The Ga-PSMA PET/CT scans identified eight of 15 patients (53.3%) as LN-positive (true positive). The calculated per-patient sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of Ga-PSMA PET/CT in the detection of LNM were 53.3%, 98.8%, 88.9%, 92.0%, and 91.7%, respectively. The per-patient sensitivity and specificity in the detection of LNMs larger than 2 mm were 61.5% and 98.8%, respectively. The main limitation is the retrospective design of the study.

Conclusions: Ga-PSMA PET/CT is accurate in lymph node staging and the results support its use for primary staging of prostate cancer.

Patient Summary: We compared prostate-specific membrane antigen (PSMA)-based positron emission tomography (PET)/computed tomography (CT) findings with histopathology results after extended lymph node dissection and showed that it is accurate in detecting lymph node metastases. Our results support the use of PSMA PET/CT for primary staging of prostate cancer.
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http://dx.doi.org/10.1016/j.euf.2021.01.004DOI Listing
March 2021

Diagnostic ability of Ga-68 PSMA PET to detect dominant and non-dominant tumors, upgrading and adverse pathology in patients with PIRADS 4-5 index lesions undergoing radical prostatectomy.

Prostate Cancer Prostatic Dis 2021 Mar 21;24(1):202-209. Epub 2020 Aug 21.

Department of Urology, School of Medicine, Koç University, Istanbul, Turkey.

Background: To evaluate the additive role of Ga-68 PSMA PET as a primary staging tool in patients bearing prostate cancer in single PIRADS 4 or 5 index lesions.

Methods: Eighty-one biopsy-naive patients with preoperative mpMRI and Ga-68 PSMA PET who underwent radical prostatectomy (RP) were evaluated retrospectively. Forty-nine patients had PIRADS 4 and 32 had PIRADS 5 index lesions. The localization, grade, and volumetric properties of dominant (DT) and non-dominant tumors (NDT) in RP were compared to the index lesions of mpMRI and Ga-68 PSMA PET.

Results: The median age and PSA level were 62 (IQR; 59-69) years and 7 (IQR; 2-8) ng/ml, respectively. Ga-68 PSMA PET detected DTs in 100% of the patients including 13 patients in whom mpMR failed. In 45 patients an NDT was reported in RP. Ga-68 PSMA PET accurately detected NDT in 24 of 45 (53.3%) patients. Six patients (12.2%) in PIRADS 4 and 8 (25%) in PIRADS 5 group showed upgrading. In PIRADS 4, Ga-68 PSMA PET localized DT in all patients with upgraded tumors whereas mpMRI missed exact location in 2 of 6 (33.3%). In PIRADS 5 both mpMRI and Ga-68 PSMA PET accurately located all DTs. Overall detection rates of extracapsular extension (ECE) and seminal vesicle invasion (SVI) by mpMRI were 51.1% and 53.8%, respectively. Ga-68 PSMA PET detected ECE and SVI in 27.9% and 30.7%, respectively. When mpMRI and Ga-68 PSMA PET were used in combination detection rates of ECE and SVI increased to 65.1 and 61.5%. Ga-68 PSMA PET-detected six of ten patients with positive lymph nodes whereas mpMRI could not identify any.

Conclusions: Ga-68 PSMA PET has a better diagnostic accuracy in detecting DT, NDT, upgrading, adverse pathology in patients with PIRADS 4 index lesions. However, mpMRI better predicted ECE and SVI than Ga-68 PSMA PET.
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http://dx.doi.org/10.1038/s41391-020-00270-8DOI Listing
March 2021

Dealing with the gray zones in the management of gastric cancer: The consensus statement of the İstanbul Group.

Turk J Gastroenterol 2019 Jul;30(7):584-598

Acıbadem Mehmet Ali Aydınlar University School of Medicine, İstanbul, Turkey.

The geographical location and differences in tumor biology significantly change the management of gastric cancer. The prevalence of gastric cancer ranks fifth and sixth among men and women, respectively, in Turkey. The international guidelines from the Eastern and Western countries fail to manage a considerable amount of inconclusive issues in the management of gastric cancer. The uncertainties lead to significant heterogeneities in clinical practice, lack of homogeneous data collection, and subsequently, diverse outcomes. The physicians who are professionally involved in the management of gastric cancer at two institutions in Istanbul, Turkey, organized a consensus meeting to address current problems and plan feasible, logical, measurable, and collective solutions in their clinical practice for this challenging disease. The evidence-based data and current guidelines were reviewed. The gray zones in the management of gastric cancer were determined in the first session of this consensus meeting. The second session was constructed to discuss, vote, and ratify the ultimate decisions. The identification of the T stage, the esophagogastric area, imaging algorithm for proper staging and follow-up, timing and patient selection for neoadjuvant treatment, and management of advanced and metastatic disease have been accepted as the major issues in the management of gastric cancer. The recommendations are presented with the percentage of supporting votes in the results section with related data.
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http://dx.doi.org/10.5152/tjg.2018.18737DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6629281PMC
July 2019

Local Salvage Treatment of Post-brachytherapy Recurrent Prostate Cancer via Theranostic Application of PSMA-labeled Lutetium-177.

Clin Genitourin Cancer 2018 04 23;16(2):99-102. Epub 2017 Sep 23.

Department of Urology, Koc University School of Medicine, Istanbul, Turkey.

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http://dx.doi.org/10.1016/j.clgc.2017.09.005DOI Listing
April 2018

Use of fluorodeoxyglucose positron emission tomography for diagnosis of bleomycin-induced pneumonitis in Hodgkin lymphoma.

Leuk Lymphoma 2017 05 13;58(5):1114-1122. Epub 2016 Oct 13.

b Koç University, School of Medicine , Department of Hematology , Istanbul , Turkey.

Bleomycin is an antineoplastic agent causing fatal pulmonary toxicity. Early diagnosis of bleomycin-induced pneumonitis is crucial to prevent irreversible damage. Pulmonary function tests are unreliable for identifying risk of bleomycin toxicity. Fluorodeoxyglucose PET/CT scanning can reveal inflammation secondary to pneumonitis but is not sufficiently specific for diagnosis. We retrospectively analyzed scans from 77 patients with Hodgkin lymphoma (median age 41 years, mean bleomycin dose 134 mg) to evaluate bleomycin-induced pneumonitis. We identified 13 patients with abnormal lung uptake of fluorodeoxyglucose. Tracer activity was predominantly diffuse, bilateral, in the lower lobes and subpleural areas. Interim scanning during treatment revealed pneumonitis in eight of 13 patients (asymptomatic in six). One asymptomatic patient died of bleomycin toxicity. For remaining 12 patients, bleomycin was discontinued and methylprednisolone given, all showed resolution of the pneumonitis. These findings suggest that routine interim or end-of-treatment FDG-PET/CT scanning could be beneficial for alerting clinicians to asymptomatic bleomycin-induced toxicity.
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http://dx.doi.org/10.1080/10428194.2016.1236379DOI Listing
May 2017

Isolated omental metastasis of renal cell carcinoma after extraperitoneal open partial nephrectomy: A case report.

Int J Surg Case Rep 2016 6;21:6-11. Epub 2016 Feb 6.

Koc University, School of Medicine, Department of Urology, Istanbul, Turkey; VKF American Hospital, Department of Urology, Istanbul, Turkey.

Introduction: Metachronous metastatic spread of clinically localized renal cell carcinoma (RCC) affects almost 1/3 of the patients. They occur most frequently in lung, liver, bone and brain. Isolated omental metastasis of RCC has not been reported so far.

Case Presentation: A 62-year-old patient previously diagnosed and treated due to pulmonary sarcoidosis has developed an omental metastatic lesion 13 years after having undergone open extraperitoneal partial nephrectomy for T1 clear-cell RCC. Constitutional symptoms and imaging findings that were attributed to the presence of a sarcomatoid paraneoplastic syndrome triggered by the development this metastatic focus complicated the diagnostic work-up. Biopsy of the [18F]-fluorodeoxyglucose (+) lesions confirmed the diagnosis of metastatic RCC and the patient was managed by the resection of the omental mass via near-total omentectomy followed by targeted therapy with a tyrosine kinase inhibitor.

Discussion: Late recurrence of RCC has been reported to occur in 10-20% of the patients within 20 years. Therefore lifelong follow up of RCC has been advocated by some authors. Diffuse peritoneal metastases have been reported in certain RCC subtypes with adverse histopathological features. However, isolated omental metastasis without any sign of peritoneal involvement is an extremely rare condition.

Conclusion: To our knowledge, this is the first reported case of metachronously developed, isolated omental metastasis of an initially T1 clear-cell RCC. Constitutional symptoms, despite a long interval since nephrectomy, should raise the possibility of a paraneoplastic syndrome being associated with metastatic RCC. Morphological and molecular imaging studies together with histopathological documentation will be diagnostic.
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http://dx.doi.org/10.1016/j.ijscr.2016.02.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4802132PMC
April 2016

The role of integrated positron emission tomography and computed tomography in the assessment of nodal spread in cases with non-small cell lung cancer.

Interact Cardiovasc Thorac Surg 2010 Feb 19;10(2):200-3. Epub 2009 Nov 19.

Department of Thoracic Surgery, Sureyyapasa Chest Disease and Thoracic Surgery Training and Research Hospital, Istanbul, Turkey.

Integrated positron emission tomography and computed tomography (PET/CT) scanning has become the standard for oncologic imaging. We sought to determine the role of PET/CT in mediastinal non-small cell lung cancer staging. One hundred and twenty-seven consecutive patients were enrolled in the study where PET/CT was performed due to pathologically defined non-small cell carcinoma from a single center. They all underwent complete resection with a thoracotomy and systemic lymph node dissection (SLND) between October 2005 and January 2007. Postoperative pathology results of lymph node stations regarding the nodal spread and stage were compared with clinical stage obtained by PET/CT. The sensitivity, specificity, accuracy, negative predictive value (NPV) and positive predictive value (PPV) of PET/CT in N2 cases were determined to be 72.0%, 94.4%, 92.7%, 97.7% and 49.2%, respectively. Maximum standard uptake (SUV(max)) cut-off value for mediastinal N2 involvement in PET/CT was obtained by applying 'receiver operating characteristic' (ROC) analysis that was set to 5.2. Correct stage with PET/CT was established in 76.3% of cases. Staging of non-small cell lung cancer (NSCLC), according to the PET/CT for which we determined 97.79% NPV, we consider that thoracotomy without preoperative mediastinal invasive staging in cases of negative mediastinal involvement in PET/CT can be certainly performed.
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http://dx.doi.org/10.1510/icvts.2009.220392DOI Listing
February 2010

Mediastinal mapping with positron emission tomography/computed tomography.

Ann Thorac Surg 2008 Apr;85(4):1457

Medica Imaging Centre, Sureyyapasa, Turkey.

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http://dx.doi.org/10.1016/j.athoracsur.2007.07.028DOI Listing
April 2008

Can exercise renography be an alternative to ACE inhibitor renography in hypertensive patients who are suspicious for renal artery stenosis?

Clin Nucl Med 2004 Jan;29(1):27-34

Department of Nuclear Medicine, Istanbul University, Istanbul Medical Facility, Turkey.

Unlabelled: The aim of this study was to evaluate the value of Tc-99m ethylenedicysteine exercise renography in patients with hypertension who were suspicious for renal artery stenosis and compare the results with captopril renography.

Methods: Twenty-nine patients with hypertension who were highly suspect for having renal artery stenosis were included in the study. Basal captopril exercise renograms were performed within 1 week in all patients with Tc-99m EC. Exercise was performed with a bicycle ergometer as described in the literature. Interpretations of renograms were made according to the consensus report on angiotensin converting enzyme (ACE) inhibitor renography as high, low, or intermediate probability. The sensitivity, specificity, and positive and negative predictive values were also obtained on both the kidneys and a patient basis. The results were compared with renal angiography in 19 patients.

Results: Twenty of 29 patients had concordant results with both captopril and exercise studies. All discordant tests were normal with captopril but positive with exercise renograms. Nineteen patients with 38 kidneys were included for statistical data analysis. Nine kidneys, which were either atrophic or abnormal during the basal study, were excluded from the kidney-based analysis. With contrast angiography, 8 patients had renal artery stenosis. When evaluated on a kidney basis, the sensitivity, specificity, and positive and negative predictive values for captopril scans were 87%, 100%, 100%, and 95%, and for the exercise scans were 100%, 90%, 80%, and 100% respectively. When calculated on a patient basis with regard to the captopril scans, the sensitivity, specificity, and positive and negative predictive values were 87%, 81%, 77%, and 88%, and for exercise scans were 100%, 54%, 61%, and 100% respectively. There were 2 false-positive exercise scans that were found to be the result of dilated minor collecting systems and changes in kidney contours as a result of motion during exercise.

Conclusions: These results indicate that exercise renography has a similar sensitivity but lower specificity compared with captopril scintigraphy in the diagnosis of renal artery stenosis. Because of the lower specificity, its use in the screening of renovascular hypertension may be limited. Exercise renography may be more useful as an investigative tool for essential hypertension.
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http://dx.doi.org/10.1097/01.rlu.0000103034.98198.26DOI Listing
January 2004