A Prospective Comparison of
            18
            F‐FDG PET/CT and CT as Diagnostic Tools to Identify the Primary Tumor Site in Patients with Extracervical Carcinoma of Unknown Primary Site

e22051 Background: Carcinoma of unknown primary (CUP) is a heterogeneous group of tumors and usually follows an aggressive biological and clinical behavior. Difficult challenges in oncology which the identification of the primary tumor and a complete disease staging could offer a more rational and efficient treatment in order to improve the survival time. Our aim was to evaluate the role of 18F-FDG PET/CT scan with two aspects: detection of the primary site, and estimation of tumor biological behavior which essential for the development of new, individual and targeted effective therapies. Methods: One hundred and seventeen patients presenting with histologically confirmed metastatic carcinoma (76 lymph nodes, 41 visceral biopsy proven) of unknown primary site were included in this retrospective study. The evaluations as follows had not revealed a primary site: detailed medical history, full physical and laboratory examinations, and diagnostic imaging methods. All patients underwent PET/CT. Results: In 42 (35.90%) patients, a primary tumor site which was confirmed by follow-up or surgery was showed by PET/CT. In 15 (12.82%) patients, the primary tumor site was suggested by PET/CT but not confirmed. In 60 (51.28%) patients, the primary tumor site was not localized modifying the stage of disease. In the other 17 (14.53%) patients, PET/CT scan identified further unexpected metastases. Overall, the following oncological treatment was influenced by the PET/CT scan, in a total of 38 (32.47%) patients. Between the adenocarcinoma and squamous cell carcinoma groups, no significant difference in SUVmax was found ( t=1.191, p = 0.244). A significantly higher SUVmax was found among patients with poorly or undifferentiated carcinoma compared with patients with well to moderately ( t=4.013, p<0.01) differentiation; In 42 patients with a confirmed primary tumor site, the SUVmax of Metastatic tumours have a closely relationship correlate with those of primary tumours, ( r=0.738, p<0.01). Furthermore, a significantly higher SUVmax was found among metastases compared with primary tumors ( t=3.470, p<0.01). Conclusions: Our data strongly support 18F-FDG PET/ CT imagings not only provide new insights in the diagnosis and staging of patients with CUP, but also evaluate biologic characters of tissue. 1 No significant financial relationships to disclose.

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A Stepwise Approach to Identify the Clinical Role of 18F-FDG PET/CT in Patients With Suspicious Bone Metastasis From an Unknown Primary Site

Clinical Nuclear Medicine ◽

10.1097/rlu.0000000000002687 ◽

2019 ◽

Vol 44 (9) ◽

pp. e524-e525 ◽

Cited By ~ 1

Author(s):

Md. Sunny Anam Chowdhury ◽

Subin Jeon ◽

Hee-Seung Bom ◽

Jung-Joon Min ◽

Seong Young Kwon

Keyword(s):

Bone Metastasis ◽

Primary Site ◽

Unknown Primary ◽

Unknown Primary Site ◽

Clinical Role ◽

Stepwise Approach ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct

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Complete biologic response to taxane based chemotherapy confirmed by [18F]FDG PET/CT and surgery in a cancer of unknown primary site

Journal of Gynecologic Oncology ◽

10.3802/jgo.2012.23.1.65 ◽

2012 ◽

Vol 23 (1) ◽

pp. 65

Author(s):

Jun-Eul Hwang ◽

Ju-Young Yoon ◽

Woo-Kyun Bae ◽

Hyun-Jeong Shim ◽

Ik-Joo Chung

Keyword(s):

Fdg Pet ◽

Cancer Of Unknown Primary ◽

Primary Site ◽

Unknown Primary ◽

Unknown Primary Site ◽

Pet Ct ◽

Biologic Response ◽

18F Fdg ◽

Fdg Pet Ct

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Clinical Impact of F-18 FDG PET-CT on Biopsy Site Selection in Patients with Suspected Bone Metastasis of Unknown Primary Site

Nuclear Medicine and Molecular Imaging ◽

10.1007/s13139-020-00649-4 ◽

2020 ◽

Vol 54 (4) ◽

pp. 192-198

Author(s):

Su Woong Yoo ◽

Md. Sunny Anam Chowdhury ◽

Subin Jeon ◽

Sae-Ryung Kang ◽

Changho Lee ◽

...

Keyword(s):

Bone Metastasis ◽

Site Selection ◽

Fdg Pet ◽

Clinical Impact ◽

Primary Site ◽

Unknown Primary ◽

Unknown Primary Site ◽

Biopsy Site ◽

Pet Ct ◽

Fdg Pet Ct

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The usefulness of [18F]FDG-PET/CT in detecting and managing cancers with unknown primary site depends on histological subtype

Scientific Reports ◽

10.1038/s41598-021-96451-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ella Nissan ◽

Uri Amit ◽

Leo Baron ◽

Amit Zabatani ◽

Damien Urban ◽

...

Keyword(s):

Fdg Pet ◽

Clinical Management ◽

Primary Site ◽

Unknown Primary ◽

Histological Subtype ◽

Unknown Primary Site ◽

Cup Syndrome ◽

Pet Ct ◽

18F Fdg ◽

Fdg Pet Ct

AbstractWe assessed the role of [18F]FDG-PET/CT in identifying and managing cancer of unknown primary site (CUP syndrome). We reviewed [18F]FDG-PET/CT scans of individuals with CUP syndrome recorded in clinical referral letters from 2012 to 2019. We evaluated the identification of primary tumor (PT) by [18F]FDG-PET/CT, according to histological subtype, and the impact on clinical management. The median age was 65 years, 36/64 males (56%). PTs were detected in 28/64 (44%) patients. Detection was significantly lower in patients with squamous cell carcinoma (SCC) than with other histologies combined, p = 0.034. Mean age, mean SUVmax (10.6 ± 6.0) and organ involvement were similar between patients with and without discovered PTs; and between patients with SCC and with other histologies combined. However, those with SCC were less likely than the others to present with multi-lesion involvement, p < 0.001. [18F]FDG-PET/CT interpretations apparently affected treatment of 8/28 (29%) patients with PT detected, and in none of the 35 whose PT was not discovered, p < 0.001. [18F]FDG-PET/CT appeared helpful in detecting PT in almost half the patients with CUP syndrome; the lowest rate was for patients with SCC pathology. PET/CT showed limited overall value in guiding clinical management, however benefited those with discovered PT.

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The value of 18F-fluordesoxyglucose positron emission tomography (FDG-PET/CT) in the detection of the primary lesion and for staging in brain metastasis (BM) patients with cancer of unknown primary site (CUPS).

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.15_suppl.2076 ◽

2017 ◽

Vol 35 (15_suppl) ◽

pp. 2076-2076

Author(s):

Emilie Le Rhun ◽

Michael Weller ◽

Anna Sophie Berghoff ◽

Elisabeth Jane Rushing ◽

Lisa Fuereder ◽

...

Keyword(s):

Fdg Pet ◽

Cancer Of Unknown Primary ◽

Primary Lesion ◽

Primary Site ◽

Emission Tomography ◽

Unknown Primary ◽

Unknown Primary Site ◽

Positron Emission ◽

Pet Ct ◽

Fdg Pet Ct

2076 Background: Brain metastasis (BM) are the first clinical presentation of cancer in around 30% of patients. They are then referred as BM from cancer of unknown primary site (BM-CUPS). The value of 18F-fluordesoxyglucose positron emission tomography (FDG-PET)/CT has not yet be determined for the management of these patients. Methods: A total of 566 patients were operated for BM at the University Hospital Zurich between 2004 and 2014, of whom 127 were identified as BM-CUPS patients. Two cohorts from other independent centers (n = 100 and 120) were used for the validation of data. Results: No difference in determining the localization of the primary lesion was observed between FDG-PET/CT and CT (FDG-PET/CT: 73/78, 93.6%; CT: n = 70/78, 89.7%; p = 0.25, McNemar’s test). The same pattern of primary lesion and other extracranial lesions was observed in 36 of 64 patients (56.3%). Additional suspicious extracranial metastases were identified by FDG-PET/CT in 28 patients (43.7%). The median graded prognostic assessment (GPA) scores were 2.5 determined according to FDG-PET/CT and 3 according to CT alone (p = 3.8x10-5), resulting in predicted survival times of 3.8 versus 5.3 months (p = 6.1x10-5; Wilcoxon’s test). Conclusions: A similar sensitivity of FDG-PET/CT and chest CT was observed for the detection of the primary tumor in BM-CUPS, however, FDG-PET/CT significantly improved the accuracy of staging. FDG-PET/CT should be preferred for the management of BM-CUPS and may help to avoid redundant CT imaging.

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