Metastasis is malignant tumor growth that occurs far from the original or main tumor. Malignant tumors have the capacity to grow in size and number, sending tumor cells through the blood or lymphatic ducts that reach specific organs and begin their multiplication in that new niche, giving rise to a new tumor that we call metastasis.
Different cancers spread to different organs. The most common organs where metastases are located are: bones, liver, lungs and brain.
What are bone metastases or bone metastases?
They are tumors located in the bones, but that occur due to the dissemination of another main or primary tumor that is located outside the bones, in another distant organ of the body.
Although the spread of cancer is mainly through the blood, there are more frequent bones where these metastases are located: pelvic bones, long bones: femur (thigh), humerus (arm), ribs and skull bones.
Difference between bone (bone) cancer and bone metastasis.
It is always important to differentiate that there is bone cancer from bone metastases, which are tumors that grow distant from an original one that has spread through the blood.
In general, bone cancer occurs in a single bone in the body, whereas bone metastases are often multiple.
Bone metastases are more common than primary bone cancer.
Symptoms of bone metastasis.
These are the signs that can occur with bone metastasis.
Pain is the main symptom of bone metastases; it tends to be worse at night. At first the pain may improve with movement but in more advanced stages it becomes intense, constant and limits mobility.
Spontaneous fractures are common, due to areas of weakness in metastatic bones. In these cases, sudden pain appears at the particular site of the fracture.
Spinal cord compression.
If there are metastases growing in the vertebrae, symptoms of compression of the spine are common: pain in the lower limbs, usually located on one side of the body, also muscle weakness in that same area, which can reach paralysis of a lower limb (legs).
In more severe cases, compression can lead to a lack of control in the urinary sphincter, generating incontinence.
High levels of calcium in the blood occur from the rapid destruction of the bones, which release large amounts of calcium into the blood. This excess calcium in the blood can generate other symptoms such as constipation, weakness, nausea, loss of appetite and neurological symptoms.
Diagnosis of bone metastases.
The diagnosis is made mainly by imaging or radiological studies.
Tumor areas of metastasis can be seen on plain X-rays, especially in cases of large lesions.
Gamma gram or bone scan.
It is the most common method for diagnosis and is the method used for post-treatment evaluation.
It can offer some details of bone metastases especially in short and flat bones. It also allows to locate the lesions well to take biopsies if necessary.
It can be used in a complementary way in some cases, mainly to locate very small metastases or to differentiate some other lesions in the bones that can occur simultaneously.
Positron emission tomography (CT-PET).
It is based on the use of a radioactive marker that binds to malignant cells and that allows to evaluate the entire body and the areas where small tumors may be growing that are not visible with other radiological methods
It also serves to monitor and measure the effectiveness of treatment.
Blood levels of calcium and alkaline phosphatase, which are markedly elevated in bone metastases, should be measured.
Tomography-guided biopsy samples or biopsies taken by surgery or open biopsies can be taken.
Biopsies in the case of bone metastases are taken in special cases when the lesion in the bone can be detected but it is not known where the primary or main tumor is located.