The role of 18F-FDG PET/CT in the evaluation of patients with cancer of unknown primary

Öz

Purpose: The aim of this retrospective study is to investigate the efficacy of 18F-FDG PET/CT in detecting primary cancer in patients with cancer of unknown primary and to compare PET/CT results with histopathological results. Materials and Methods: The data of 134 patients who presented to our clinic with the diagnosis of malignancy with unknown primary and underwent 18F-FDG PET/CT scan were examined from the hospital information system. PET CT scans of 114 of these patients, whose histopathological examination was completed, were re-evaluated by two experienced nuclear medicine specialists. PET/CT results were compared with histopathological findings. Sensitivity, specificity and accuracy of 18F-FDG PET/CT were calculated. In this patient series, the ratio of the confirmed CUP was calculated. Results: A total of 114 patients (56 women, 58 men) aged 13-90 years were included in the study. The mean age of the patients was 60.53 ± 17.04 years. Histopathologically, 73 (64%) patients were malignant and 41/114 (36%) patients were benign. According to 18F-FDG PET/CT, 83 (73%) patients were evaluated as malignant and 31 (27%) patients as benign or primary or metastatic. 18F-FDG PET/CT was able to accurately detect primary focus in 65 (89%) of 73 patients with histopathologically confirmed malignancy. 18F-FDG PET / CT could not identify the primary tumor site in 8 (11%) of 73 patients. Two of these eight patients were plasma cell myeloma, one was multible myeloma and one patient was lymphoma. Therefore, 4 (6%) patients were accepted as confirmed cancer of unknown primary. Overall, the diagnostic accuracy was found to be 78%, sensitivity 89%, specificity %56%,positive predictive value %78.5, negative predictive value%74. Conclusion: 18F-FDG PET/CT is highly successful in determining the primary cancer focus in patients with CUP due to its full body scanning advantage and high sensitivity.

Anahtar Kelimeler

• cancers of unknown primary,fluorodeoxyglucose

Primeri bilinmeyen maligniteli hastaların değerlendirilmesinde 18F-FDG PET/BT’nin rolü

Öz

Amaç: Bu retrospektif çalışmanın amacı, 18F-FDG PET/BT'nin primeri bilinmeyen kanserli hastalarda primer kanseri saptamadaki etkinliğini araştırmak ve PET/BT sonuçlarını histopatolojik sonuçlarla karşılaştırmaktır. Gereç ve Yöntem: Kliniğimize primeri bilinmeyen malignite öntanısıyla başvuran ve 18F-FDG PET/BT taraması yapılan 134 hastanın bilgileri hastane bilgi sisteminden incelendi. Bu hastalardan histopatolojik incelemesi tamamlanmış olan 114 tanesinin PET/BT taramaları iki deneyimli nükleer tıp uzmanı tarafından yeniden değerlendirildi. PET/BT sonuçları histopatolojik bulgularla karşılaştırıldı. 18F-FDG PET/BT’ nin sensitivite, spesifite ve doğruluk oranları hesaplandı. Bu hasta serisinde doğrulanmış primeri bilinmeyen kanser oranı hesaplandı. Bulgular: Çalışmamıza 56 kadın, 58 erkekten oluşan, yaşları 13-90 arasında 114 hasta dahil edildi. Hastaların ortalama yaşı: 60,53±17,04 yıl idi. Histopatolojik olarak 73 (%64) hasta malign, 41 (%36) hasta benign idi. 18F-FDG PET/BT’ye göre primer veya metastatik olarak toplam 83(%73) hasta malign, 31(%27) hasta benign olarak değerlendirildi. 18F-FDG PET/BT histopatolojik olarak malignitesi kanıtlanmış 73 hastanın 65’inde(%89) primer odağı doğru tespit edebildi. 18F-FDG PET/BT, 73 hastanın 8’ inde (% 11) primer tümör bölgesini tanımlayamadı. Bu sekiz hastanın ikisi plazma hücreli myelom, biri multible myelom ve bir hasta lenfoma idi. Bu nedenle 4(%6) hasta doğrulanmış primeri bilinmeyen kanser olarak kabul edildi. Genel olarak, tanısal doğruluk %78, duyarlılık%89, özgüllük%56, pozitif öngörü değeri% 78,5, negatif öngörü değeri% 74 olarak bulundu. Sonuç: 18F-FDG PET/BT primeri bilinmeyen malignite hastalarında tüm vücut tarama avantajı ve sensitivitesinin yüksek olması nedeniyle primer kanser odağını belirlemede oldukça başarılıdır.

Anahtar Kelimeler

• Primeri bilinmeyen kanser,florodeoksiglukoz,pozitron emisyon tomografisi

Kaynakça

1. 1. Oien KA. Pathologic evaluation of unknown primary cancer. Semin Oncol 2009;36:8-37. doi: 10.1053/j.seminoncol.2008.10.009.
2. 2. Fizazi K, Greco FA, Pavlidis N, Daugaard G, Oien K, Pentheroudakis G. ESMO Guidelines Committee Cancers of unknown primary site:ESMO clinical practice guidelines for diagnosis, treatment and follow-up. Ann Oncol 2015;26:133-138. doi: 10.1093/annonc/mdv305.
3. Wagland R, Bracher M, Drosdowsky A et al. Differences in experiences of care between patients diagnosed with metastatic cancer of known and unknown primaries: mixed-method findings from the 2013 cancer patient experience survey in England. BMJ Open 2017 27;7:e017881. doi: 10.1136/bmjopen-2017-017881.
4. 4. Losa F, Iglesias L, Pané M et al. 2018 consensus statement by the Spanish Society of Pathology and the Spanish Society of Medical Oncology on the diagnosis and treatment of cancer of unknown primary. Clin Transl Oncol 2018;20:1361-1372. doi: 10.1007/s12094-018-1899-z.
5. 5. Jones W, Allardice G, Scott I, Oien K, Brewster D, Morrison DS. Cancers of unknown primary diagnosed during hospitalization: a population-based study. BMC Cancer 2017;17:85. doi: 10.1186/s12885-017-3083-1.
6. 6. Dyrvig AK, Yderstræde KB, Gerke O et al. Cancer of unknown primary: registered procedures compared with national integrated cancer pathway for illuminating external validity. Medicine(Baltimore) 2017;96:e6693. doi:10.1097/MD.0000000000006693.
7. 7. Uzunoglu S, Erdogan B, Kodaz H, et al. Unknown primary adenocarcinomas: a single-center experience. Bosn J Basic Med Sci 2016;16:292-297. doi:10.17305/bjbms.2016.1495.
8. 8. Qaseem A, Usman N, Jayaraj JS, Janapala RN, Kashif T. Cancer of unknown primary: A review on clinical guidelines in the development and targeted management of patients with the unknown primary site. Cureus 2019;11:e5552. doi: 10.7759/cureus.5552.

9. 9. Kwee TC, Kwee RM. Combined FDG-PET/CT for the detection of unknown primary tumors: systematic review and meta-analysis. Eur Radiol 2009;19:731-744. doi: 10.1007/s00330-008-1194-4.
10. 10. Seshadri N, Eswar C,Jayan R. Radiological imaging in cancer of unknown primary. In: Seshadri N, Eswar C, eds. PET/CT in cancer of unknown primary. 1rd ed. Cham: Springer International Publishing, 2017;15-22
11. 11. Yu X, Li X, Song X, et al. Advantages and disadvantages of F-18 fluorodeoxyglucose positron emission tomography/computed tomography in carcinoma of unknown primary. Oncol Lett 2016;12:3785-3792.
12. Pawaskar AS, Basu S. Role of 2-Fluoro-2-Deoxyglucose PET/Computed Tomography in carcinoma of unknown primary PET clin. 2015l;10:297-310. doi:10.1016/j.cpet.2015.03.004.
13. 13. Gutzeit A, Antoch G, Kühl H, et al. Unknown primary tumors: detection with dual-modality PET/CT--initial experience. Radiology 2005;234:227-234.
14. 14. Riaz S, Nawaz MK, Faruqui ZS, Saeed Kazmi SA, Loya A, Bashir H. Diagnostic accuracy of 18F-Fluorodeoxyglucose positron emission tomography-computed tomography in the evaluation of carcinoma of unknown primary. Mol Imaging Radionucl Ther 2016;25:11-18. doi: 10.4274/mirt.05706.
15. 15. Han A, Xue J, Hu M, Zheng J, Wang X. Clinical value of 18F-FDG PET-CT in detecting primary tumor for patients with carcinoma of unknown primary. Cancer Epidemiol 2012;36:470-475. doi: 10.1016/j.canep.2012.03.002.
16. 16. Zhao K, Luo XM, Zhou SH, et al. ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography as an effective diagnostic workup in cervical metastasis of carcinoma from an unknown primary tumor. Cancer Biother Radiopharm 2012; 27:685-693. doi:10.1089/cbr.2011.1134.
17. 17. Fleming AJ Jr, Smith SP Jr, Paul CM, et al. Impact of [18F]-2-fluorodeoxyglucose-positron emission tomography/computed tomography on previously untreated head and neck cancer patients. Laryngoscope 2007;117:1173-1179.
18. 18. Tamam C, Tamam M, Mulazimoglu M. The Accuracy of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in the evaluation of bone lesions of undetermined origin. World J Nucl Med 2016;15:124-129. doi: 10.4103/1450-1147.176885.
19. 19. Pelosi E, Pennone M, Deandreis D, Douroukas A, Mancini M, Bisi G. Role of whole body positron emission tomography/computed tomography scan with 18F-fluorodeoxyglucose in patients with biopsy proven tumor metastases from unknown primary site. Q J Nucl Med Mol Imaging 2006;50:15-22.
20. 20. Yapar Z, Kibar M, Yapar AF et al. The value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in carcinoma of an unknown primary: diagnosis and follow-up. Nucl Med Commun 2010;31:59-66. doi: 10.1097/MNM.0b013e328332b340.
21. 21. Kwee TC, Basu S, Cheng G, Alavi A. FDG PET/CT in carcinoma of unknown primary.Eur J Nucl Med Mol Imaging 2010;37:635-644. doi:10.1007/s00259-009-1295-1296.
22. 22. Pavlidis N, Briasoulis E, Hainsworth J, Greco FA. Diagnostic and therapeutic management of cancer of an unknown primary. Eur J Cancer 2003;39:1990-2005.
23. 23. Yaylalı O, Kıraç FS, Yüksel D. The role of 18F-FDG PET-CT in the detection of unknown primary malignancy: a retrospective study. Turk J Med Sci 2016;17:474-482. doi: 10.3906/sag-1502-99.
24. 24. Cengiz A, Göksel S, Yürekli Y. Diagnostic value of (18)F-FDG PET/CT in patients with carcinoma of unknown primary. Mol Imaging Radionucl Ther 2018;27:126-132. doi: 10.4274/mirt.64426