Carcinoma of unknown primary
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Carcinoma of unknown primary (CUP) is a diagnosis given when the cancer is discovered in the body but unable to pinpoint the origin of a tumor. The cancer has spread to another part of the body and the abnormal cell features do not lead to the discovery of where the disease originated. This condition is also known as occult primary cancer.
Cancer can begin in any tissue of the body. The primary location defines the cancer. If the cancer originates in the liver and travels (metastasizes) to the lungs, it is still referred to as liver cancer, not lung cancer. Cancer alters the appearance of a cell type. Doctors can tell if cancer has spread when they identify abnormal cell types in the organs where they should not be.
If a carcinoma of unknown primary is discovered, clinicians seek to determine the primary tumor site. When determining where the cancer started, the doctor may evaluate the risk factors, symptoms, and the findings of exams, imaging tests, and laboratory testing. The treatment is determined by taking the location of the original tumor into account.
Symptoms
There are no distinct symptoms associated with cancer of unknown primary. The signs and symptoms depend on which portion of the body is affected. Common signs and symptoms include:
- Pain, especially in the abdomen or chest
- Any bulge, lump or thickening in the body
- Cough or hoarseness of voice
- Constipation, diarrhea, or frequent urination
- Fever
- Sweating at night
- Unexpected weight loss or appetite loss
- Fatigue
- Abnormal bleeding or discharge
Causes
Cancer can be caused by a variety of factors. It is very difficult to pinpoint a specific cause of carcinoma of unknown primary since the original site of the malignancy is unknown.
Cancer is usually caused by mutations in the DNA of cells. DNA provides instructions that direct cells on what to perform. These abnormal cells then divide, multiply, and possibly spread to other parts of the body. Cancer cells that have spread to other places of the body are observed in carcinoma of unknown primary. However, the primary tumor is not discovered.
Carcinoma of unknown primary can occur if:
- The origin of the cancer is too minor for imaging tests to detect
- The immune system of the body killed the original cancer
- There was a surgery for another condition and the original cancer was unknowingly removed during the operation
Risk factors
There are several factors that affects one’s risk of getting carcinoma of unknown primary, such as:
- Age: People with ages 60 and older are at a higher risk of getting this disease.
- Family history of cancer: Family history of lungs, kidney, or colon cancer may be linked to a higher risk of carcinoma of unknown primary.
Diagnosis
The diagnosis of carcinoma of unknown primary requires assessment of signs and symptoms, evaluating the patient’s medical history, current medications, vitamins, supplements, or other therapies, and performing a physical examination. The physical exam often entails inspecting the affected area or looking for tumors, swollen lymph nodes, or anything odd.
Several tests and procedures may be required, such as:
- Imaging tests: Scans provide detailed images of the inside of the body. CT, MRI, PET, mammogram, and X-ray are the type of scans that may be necessary.
- Biopsy: A biopsy will be performed if the lump is discovered or if the symptoms or initial test indicates possible cancer. A biopsy involves the removal of cells or tissue from the body for lab testing to see whether they are malignant and where they came from. The procedure involves inserting a needle through the skin or during surgery.
- Tests to look for the original cancer: Tests may aid the healthcare provider in locating the original tumor where the cancer began. If the primary tumor is discovered, one will no longer be diagnosed with carcinoma of unknown primary. If initial tests reveal cancer cells that originated elsewhere in the body, one may be subjected to additional testing to determine the location of the cancer cells’ origin or primary tumor.
Tests may include:
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- Physical examination: A thorough examination for symptoms of cancer will be performed.
- Imaging studies: The tests, such as CT and positron emission tomography (PET), can indicate details of abnormal areas, how far cancer has gone, and where the cancer may have begun.
- Blood tests: These tests detect higher- or lower-than-normal quantities of chemicals released into the bloodstream by the tissues and organs in the body. They can monitor organ function which can provide the doctor with information about whether cancer has affected the organs, such as the liver and kidneys.
A tumor marker test may check for chemicals produced by types of cancer which may provide further information for the diagnosis. Tumor markers are chemicals secreted into the bloodstream by some malignancies. Tumor markers include prostate-specific antigen (PSA) for prostate cancer, alpha-fetoprotein (AFP) for liver cancer, and CA-125 for ovarian cancer.
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- Endoscopy: Using an endoscope, the organs and tissues may be examined. An endoscope is a narrow, tube-like device that has a light and a lens for seeing as well as a tool for removing tissue samples. The scope may be passed through the mouth and into the lungs, esophagus, stomach, liver, or small intestine. The scope can be put into the anus to inspect the colon and rectum.
- Advanced lab testing: A pathologist may employ several types of high-powered microscopes as well as dyes, stains, or chemicals to magnify cell features and detect changes in cell DNA. Certain cell alterations or features have been connected to different types of cancer. This extensive test can provide more information for the diagnosis.
Treatment
Since carcinoma of unknown primary has already spread and the primary cancer site might not be identified, the treatment will depend on what is known and what is regarded to be the most likely type of cancer. The treatment strategy is tailored to the patients’ specific clinical circumstances as well as their personal preferences.
Common treatment options include:
- Chemotherapy: Chemotherapy is recommended if cancer is suspected in more than one location. One or more medications to kill cancer cells are used for this type of treatment. It can be administered through a vein, or consumed orally.
- Radiation therapy: If cancer is deemed to be localized, radiation therapy is utilized. It can also help with reducing symptoms, such as discomfort caused by a growing malignancy. Radiation therapy kills cancer cells by delivering high-energy beams from sources such as X-rays and protons. External radiation often involves the use of radiation beams directed towards the cancer, while internal radiation uses radioactive seeds, wires, needles, or catheters implanted in or near the malignancy.
- Surgery: This method is utilized if the cancer is deemed to be localized such as a lymph node or the liver. The doctor will remove the malignancy as well as a little amount of good tissue surrounding it. To eliminate any leftover cancer cells, radiation or chemotherapy may be used.
- Palliative care: This is often recommended in conjunction with more severe therapies like surgery, chemotherapy, or radiation therapy. This treatment focuses on relieving pain and other symptoms of cancer. Additional support to the existing treatment is provided by specialized professionals in collaboration with the patients, their doctors, and families.
