Sandbox: maria6
Synonyms and keywords: Occult cancer; CUP; Metastases of unknown primary origin; Unknown primary origin neoplasm; cancers of unknown primary site; neoplasms of unknown primary site

# Overview

# Historical Perspective
- Cancer of unknown primary origin was first discovered by , a , in  during/following .
- In ,  mutations were first identified in the pathogenesis of cancer of unknown primary origin.
- In , the first  was developed by  to treat/diagnose cancer of unknown primary origin.

# Classification
- Cancer of unknown primary origin may be classified according to  into  subtypes/groups:
- Other variants of cancer of unknown primary origin include , , and .

# Pathophysiology
- The pathogenesis of Cancer of unknown primary origin is characterized by , , and .
- The  gene/Mutation in  has been associated with the development of cancer of unknown primary origin, involving the  pathway.
- On gross pathology, , , and  are characteristic findings of Cancer of unknown primary origin.
- On microscopic histopathological analysis, , , and  are characteristic findings of Cancer of unknown primary origin.

# Causes
- Cancer of unknown primary origin may be caused by either , , or .
- Cancer of unknown primary origin is caused by a mutation in the , , or  gene.
- There are no established causes for cancer of unknown primary origin.

# Differentiating Cancer of Unknown Primary Origin from Other Diseases
- Cancer of unknown primary origin must be differentiated from other diseases that cause , , and , such as:

# Epidemiology and Demographics
- The prevalence of cancer of unknown primary origin is approximately  per 100,000 individuals worldwide.
- In , the incidence of Cancer of unknown primary origin was estimated to be  cases per 100,000 individuals in .

## Age
- Patients of all age groups may develop cancer of unknown primary origin.
- Cancer of unknown primary origin is more commonly observed among patients aged  years old.
- Cancer of unknown primary origin is more commonly observed among .

## Gender
- Cancer of unknown primary origin affects men and women equally.
-  are more commonly affected with cancer of unknown primary origin than .
- The  to  ratio is approximately  to 1.

## Race
- There is no racial predilection for cancer of unknown primary origin.
- Cancer of unknown primary origin usually affects individuals of the  race.
-  individuals are less likely to develop Cancer of unknown primary origin.

# Risk Factors
- Common risk factors in the development of cancer of unknown primary origin are , , , and .

# Natural History, Complications and Prognosis
- The majority of patients with cancer of unknown primary origin remain asymptomatic for .
- Early clinical features include , , and .
- If left untreated,  of patients with Cancer of unknown primary origin may progress to develop , , and .
- Common complications of Cancer of unknown primary origin include , , and .
- Prognosis is generally , and the  of patients with Cancer of unknown primary origin is approximately .

# Diagnosis

## Diagnostic Criteria
- The diagnosis of cancer of unknown primary origin is made when at least  of the following  diagnostic criteria are met:

## Symptoms
- Cancer of unknown primary origin is usually asymptomatic.
- Symptoms of cancer of unknown primary origin may include the following:

## Physical Examination
- Patients with cancer of unknown primary origin usually appear .
- Physical examination may be remarkable for:

## Laboratory Findings
- There are no specific laboratory findings associated with cancer of unknown primary origin.
- A    is diagnostic of cancer of unknown primary origin.
- An  concentration of   is diagnostic of Cancer of unknown primary origin.
- Other laboratory findings consistent with the diagnosis of Cancer of unknown primary origin include , , and .

## Imaging Findings
- There are no  findings associated with cancer of unknown primary origin.
-  is the imaging modality of choice for cancer of unknown primary origin.
- On , Cancer of unknown primary origin is characterized by , , and .
-  may demonstrate , , and .

## Other Diagnostic Studies
- Cancer of unknown primary origin may also be diagnosed using .
- Findings on  include , , and .

# Treatment

## Medical Therapy
- There is no treatment for cancer of unknown primary origin; the mainstay of therapy is supportive care.
- The mainstay of therapy for cancer of unknown primary origin is  and .
-  acts by .
- Response to  can be monitored with  every .

## Surgery
- Surgery is the mainstay of therapy for cancer of unknown primary origin.
-  in conjunction with  is the most common approach to the treatment of Cancer of unknown primary origin.
-  can only be performed for patients with  Cancer of unknown primary origin.

## Prevention
- There are no primary preventive measures available for cancer of unknown primary origin.
- Effective measures for the primary prevention of cancer of unknown primary origin include , , and .
- Once diagnosed and successfully treated, patients with Cancer of unknown primary origin are followed-up every . Follow-up testing includes , , and .