The secondary bone cancer (or bone metastases) is among the more common forms. This type of bone tumor, due to another cancer that is metastasized, presents a rather pessimistic prognosis , depending on the stage of the disease.
Secondary cancers of the bones: frequent tumors
Secondary bone cancer occurs when a cancer affecting another organ spreads and develops in the bones. It is said that cancer metastasis . Bone cancer is therefore the result of a first cancer, hence its “secondary”. The following characteristics can be noted:
- In the case of bone metastases, dissemination occurs almost exclusively via the blood .
- Secondary cancers of the bones constitute a particularly frequent complication of certain cancers since it is estimated that half of the new cases of cancer develops bone metastases . This is the third secondary cancer after those of the lung and the liver.
To note : the secondary bone cancer is much more common than primary cancers, that is to say those which originate directly in the bones .
Major Cancers Causing Bone Metastases
In medicine, it is considered, until proof to the contrary, that all bone lesions of tumor appearance occurring in people over the age of 50 years are bone metastases :
- Before age 55, women are most affected by the development of breast cancer.
- Between the ages of 55 and 70, men and women are equally concerned with each other.
- After 70 years, men are the most affected because of the presence of prostate cancers.
The most common cancers that result in bone metastases are (in descending order of frequency):
- the breast cancer (bone metastases are found in about 70% of cases of advanced breast cancer);
- the prostate cancer (90% of men died from prostate cancer bone metastases present);
- the cancer of the lung and bronchus (lung cancer);
- the kidney cancer ;
- the thyroid cancer ;
- the pancreatic cancer ;
- the colon cancer ;
- the stomach cancer ;
- the liver cancer .
Localization of secondary bone cancers
The metastases that affect the bones often affect the same areas. The most frequently affected are (in descending order):
- The lumbar vertebrae (lower back);
- The upper part of the femur (upper thigh);
- The pelvis (iliac bones, sacrum and coccyx);
- The dorsal vertebrae ;
- The coasts ;
- The upper limb and in particular the humerus (arm);
- The skull .
Good to know : these localizations are the most common, but bone metastases can affect all bones without exception.
Secondary cancers of the bones: simultaneous appearance of metastases
Concerning the simultaneity of bone metastases (among themselves or with other types of metastases), we can list the following cases:
- In about 70% of cases , several bone metastases occur simultaneously.
- 74% of isolated metastases remain intact throughout the course of cancer.
- In addition, bone metastases may occur at the same time as other types of metastasis (as shown in the table below).
- On the other hand, if the tumor has metastasized in various zones of the same bone, we speak of discontinuous metastases.
Joint Appearances Between Different Types of Metastasis
Consequences of bone metastases
Whatever the regions affected, as soon as there is cancer , bone metastases will lead to abnormal activity:
- It can be the destruction of bone cells (by activating the osteoclasts ). It is this process which is the most frequent ( almost 87% of the cases ):
- It occurs mainly in the case of kidney, thyroid, bronchial or digestive cancers.
- Radiography shows bone areas that are radiotransparent , that is, black, instead of white.
- This type of metastasis is often accompanied by spontaneous fractures .
- More rarely ( 3% of cases ), it can also be the production of bone cells (by activating the osteoblasts):
- This type of metastasis produces mainly in the case of breast or prostate cancers.
- Diffuse images, especially of the vertebrae and pelvis, are observed on the radiograph.
- This type of metastasis is rarely accompanied by fractures.
- There are also mixed forms which are found in 10% of cases :
- On radiography, a bone with a flaky appearance is observed.
- Here, too, they are observed mainly in the context of breast cancer.
- significant bone pain ;
- of paralysis when they affect the surrounding tissues;
- of fractures even without trauma.