Carcinoma of unknown primary (CUP); some considerations about pathogenesis and diagnostic strategy, particularly focusing on CUPS pertaining to the Urology
The term "carcinoma of unknown primary" (CUP) defines a malignant condition in which a metastatic cancer is documented in absence of a detectable primary site. It occurs in about 2÷6 % of cancer patients, according to various literature reports. The primary tumor site results indefinable because of several either single or associated factors, even remaining occult at autopsy in 15÷25% of CUP patients. The metastatic spread pattern of CUP is quite unlike that expected for analogous known primary malignancy. For instance, the unknown prostate cancer often metastasizes to the lungs and liver while the its known analogous usually spreads to the bone. Whether certain genetic abnormalities might play a role in determining a CUP condition, it remains undefined. Most CUP are adenocarcinoma, squamous cell carcinoma, either undifferentiated or differentiated carcinoma, whereas less frequently may be sarcoma, melanoma or neuroendocrine tumor. As CUP diagnostic management is concerned, two opposite approach modalities may be adopted, one, named "shotgun modality", consisting in a multiplicity of examinations aimed at achieving the identification of the primary tumor and the other, a nihilistic modality, by adopting tout court a palliative therapy of the metastatic disease. A reasonable intermediate diagnostic strategy consists in undertaking some procedures with a specific target and low cost/benefit ratio. Selected imaging studies, serum tumor markers, immunohistochemical analyses and genetic- molecular examinations on biopsy material allow sometimes to reach the detection of primary malignancies that might be responsive to a potential treatments. Nevertheless, in spite of recent sophisticated -laboratory and imaging progress, CUP remains a strong challenge in clinical oncology.
Available from: Ryujiro Suzuki
- "A primary tumor may not be detected because of its extremely small size or possible local regression due to antitumor immune defenses as well as its protracted clinical latency . Since it is difficult to detect the organs where the primary tumor is located, investigation with imaging, tumor marker and IHC markers is performed to at least classify the type of carcinomas. "
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ABSTRACT: About 3% of all cancer patients suffer from carcinoma of unknown primary site (CUP). In spite of its rarity, we will encounter them. While CUPs manifest a wide variety of clinical presentations, they have often resulted in poor prognosis. Although platinum/taxane combination chemotherapy, e.g. carboplatin (CBDCA) + paclitaxel (PTX) is widely used for patients suffering from CUP, the response rate is only about 30-40% and the median overall survival (OS) is only 9 months, which means that improvement is needed. Among the new regimens, the combination of CBDCA, PTX, bevacizumab (BEV) and erlotinib is thought to be highly promising. Herein, we report a case with CUP treated with this regimen and his maintenance therapy. Our patient was a 75-year-old man who was admitted with a left neck lump. CT revealed systemic massive lymphadenopathy. In spite of various investigations for primary origin, he was diagnosed with CUP and treated with CBDCA + PTX + BEV + erlotinib (AUC 6 + 175 mg/m(2) + 15 mg/kg + 150 mg). Since the evaluation of the efficacy indicated partial response, maintenance chemotherapy (BEV and erlotinib) was performed. Chemotherapy was continued for 9 months until the patient was in a progressive disease state with meningeal dissemination. He died 12 months after the initiation of chemotherapy, which is a longer period than the previously reported OS. Of note, according to our case, CBDCA + PTX + BEV + erlotinib and its maintenance chemotherapy are feasible and well tolerated for CUP.
Available from: Yasuhiro Hashimoto
- "In patients with CUP with skeletal metastases, the prostate was the second most common primary site. A recent review of CUP in the urogenital system reported the frequency of CUP of the prostate to be 4% . "
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ABSTRACT: Prostate-specific antigen (PSA) is a widely used specific tumor marker for prostate cancer. We experienced a case of metastatic prostate cancer that was difficult to detect by repeat prostate biopsy despite a markedly elevated serum PSA level.
A 64-year-old man was referred to our hospital with lumbar back pain and an elevated serum PSA level of 2036 ng/mL. Computed tomography, bone scintigraphy, and magnetic resonance imaging showed systemic lymph node and osteoblastic bone metastases. Digital rectal examination revealed a small, soft prostate without nodules. Ten-core transrectal prostate biopsy yielded negative results. Androgen deprivation therapy (ADT) was started because of the patient's severe symptoms. Twelve-core repeat transrectal prostate biopsy performed 2 months later, and transurethral resection biopsy performed 5 months later, both yielded negative results. The patient refused further cancer screening because ADT effectively relieved his symptoms. His PSA level initially decreased to 4.8 ng/mL, but he developed castration-resistant prostate cancer 7 months after starting ADT. He died 21 months after the initial prostate biopsy from disseminated intravascular coagulation.
CUP remains a considerable challenge in clinical oncology. Biopsies of metastatic lesions and multimodal approaches were helpful in this case.
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ABSTRACT: Das sog. CUP-Syndrom (,,carcinoma of unknown primary“) stellt den diagnostizierenden Arzt und den betroffenen Patient vor eine große Herausforderung. Mittels differenzierter pathologischer Diagnostik kann zunächst die Morphologie genauer beschrieben, durch ergänzende immunhistochemische Untersuchungen können weitere Eigenschaften identifiziert und somit eine mögliche Zuordnung zu einem Primärgewebe erreicht werden. Dadurch wird die Suche nach einem latenten Primärtumor erleichtert, und Möglichkeiten zur Therapieoptimierung werden erschlossen. Als letzter Schritt können molekularbiologische Untersuchungen das diagnostische Repertoire erweitern.
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