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Case History

Image not available. A 65-year-old smoker presents with pain in the right hip and a plain radiograph shows a lytic lesion with a pathological fracture in the neck of the right femur. He has been reasonably well prior to this and a good-quality chest radiograph is reported as showing normal findings.

What investigations are indicated? How extensive should be the search for the primary?

What is the value of serum tumour markers in the diagnosis of an unknown primary?

What about emerging technologies such as gene profiling?

What are the basic principles to guide management - looking for the treatable?

Assuming the final diagnosis is carcinoma of unknown primary, what are the results from treatment with chemotherapy?

What are the options and the optimal local treatment for the fracture?

Background

What investigations are indicated? How extensive should be the search for the primary?

Image not available. A cancer of unknown primary origin is defined as a biopsy-proved cancer that could not have arisen at the site of biopsy, with no primary tumour found after a careful history, physical examination and diagnostic work-up. The physical examination of a man with an unknown primary should include a testicle and prostate examination. A computed tomography (CT) scan of the thorax, abdomen and pelvis is the most appropriate radiological investigation to assess the extent of disease and to identify any potential primary sites of disease. Conventional radiography is, however, unable to determine the primary site of disease in most cases of UKP. Recently, positron emission tomography (PET) scans have been evaluated in the diagnostic work-up of unknown primary. The strongest evidence to support the use of PET is in patients with head and neck cancer. PET will identify primary sites of disease in up to a third of such patients in whom the sites have not been found on conventional radiography.1 In patients with extracervical metastatic disease, primary sites of disease may be identified but the clinical benefit and cost-effectiveness is uncertain and needs to be confirmed by larger studies.

In this patient with pathological fracture a bone scan may also be useful to assess the extent of the bony disease. He requires a bone biopsy with routine light microscopy and immunohistochemistry carried out by an experienced histopathologist who may be able to define potential organs of origin. Assuming the pathologist excludes a primary bone tumour, the working diagnosis is that of unknown primary cancer.

What is the value of serum tumour markers in the diagnosis of an unknown primary?

In men presenting with adenocarcinoma and bone metastases, a serum prostate-specific antigen (PSA) level can be useful to identify those with possible prostate cancer. In men in whom the histological examination shows poorly differentiated carcinomas, serum levels of human chorionic gonadotrophin (hCG) and α-fetoprotein (AFP) should be measured as significantly raised levels raise the possibility of a germ cell ...

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