Cancer of Unknown Primary

1 What is Carcinoma of Unknown Primary?

Carcinoma of unknown primary, also called occult primary tumor, is a disease in which the site of origin of cancer is not detectable. Your doctor are able to detect the cancer that has spread to other parts of your body but the place where it first began cannot be found.
The signs and symptoms of this rare disease vary and depend upon the place where the cancer has spread. Tests and procedures used for diagnosis also depend upon the place where it has spread.

Cancer can affect any tissues of your body. The cancer that formed first is called a primary cancer. Some types of cancer cells may spread to other parts of your body in a process called metastasis.
In case of carcinoma of unknown primary, it is not possible to determine where the cancer first started.

2 Symptoms

The signs and symptoms of carcinoma of unknown primary depend upon the organ where it has spread.

Since the patients with carcinoma of unknown origin are typically in advanced state, they are most likely to have following common symptoms:

  • Loss of weight
  • Weakness
  • Tiredness
  • General feeling of illness

Apart from these common symptoms, the patients may present with clinical manifestations specific to the type of cancer that has spread to a body part.

3 Causes

Like many other cancers, it is hard to determine the cause of carcinoma of unknown primary, but it is a combination of environmental and dietary factors that make you more vulnerable.

In carcinoma of unknown primary, it is assumed that the original tumor from where the cancerous cells started spreading is too small to be detected by current diagnostic methods.
Genetic factors combined with environmental and dietary factors make you more vulnerable to carcinoma of unknown primary.

Like other cancers, many cancers of unknown primary are linked to smoking. Therefore, quitting smoking is a good idea to reduce the risk of any type of cancer.

4 Making a Diagnosis

Making a diagnosis of Carcinoma of unknown primary is done by performing several tests.

It is a normal understanding in carcinoma of unknown primary that the cancer spreads to other body parts before it is apparent at the site of origin.

Your doctor can look for certain cancer signs at the affected part which might hint at the site where it first originated. For example, ascites could signal the origin of cancer in ovary and axillary tumor in a female could indicate breast cancer as the primary cancer.

Your doctor can recommend following diagnostic tests in an attempt to locate the origin of the cancer:

  • Complete blood cell count: Blood is drawn and analyzed in the lab to find if different blood components are within the normal range.
  • Analysis of urine and stool
  • Test to determine how well your liver is functioning (Liver function test)
  • Test to determine how well your kidneys are functioning (Renal Function test)
  • CT Scan of abdomen and pelvis in women
  • PSA (Prostate specific antigen) measurement in men
  • Biopsy: A small sample of tissue from the affected part is taken and studied under microscope to determine the type of cancer.
  • Chest radiograph
  • Mammography in women

5 Treatment

Doctors design treatment strategy based on where your cancer started, not possible in case of carcinoma of unknown primary.

In case of carcinoma of unknown primary, your doctors work on various factors that might hint at a specific origin of the cancer.

The treatments include:

  • Surgery
  • Radiation therapy
  • Medications: Various anticancer agents like paclitaxel, carboplatin can be recommended to induce remission or prevent further complications.
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