Scientists have discovered a
substance that accelerates the death of tumor cells and reduces its ability to
divide at the molecular level. This substance (natural flavonoid) reduces the
phosphorylation of proteins and blocks the signaling pathway, which leads to a
decrease in DNA-binding proteins. As a result, tumor growth slows down. The
Malignant bone tumors are divided
into two types - primary and secondary. Primary is a tumor of bone tissue;
secondary - metastases in bone tissue if there is already a primary tumor, such
as lung or breast. Malignant neoplasms from bone tissue are rare (per 100,000
population - from one to five new cases). If detected at a late stage, the
prognosis is unfavorable.
Ewing's sarcoma, chondrosarcoma
and osteosarcoma are most often diagnosed among primary bone tumors. Ewing's
sarcoma and osteosarcoma occur as a result of the growth of bone tissue, with
chondrosarcoma there is a degeneration of cartilage cells. Ewing's sarcoma is a
bone tumor that is most common in children.
When metastases are detected in
the bones, the primary source must be found in some organ. Bone metastases most
often give the prostate, lungs, thyroid, breast. These malignant tumors spread
cancer cells in blood vessels, stimulate bone tissue to destruction or to the
appearance of tumors.
DIAGNOSIS
In usa diagnosis of bone tumors,
in addition to examination, collection of medical history and standard blood
tests, involves:
clinical examination;
use of medical imaging methods:
·
computed tomography;
·
ultrasound;
·
radiographic method;
morphological diagnosis with the establishment of the type of tumor;
immunohistochemically and
molecular biology methods (studies are conducted in reference laboratories in
Israel and Germany).
X-ray examination is the first
and important diagnostic test. Sarcomas have a characteristic picture on the
radiograph. In this case, there are either dark spots in the affected areas of
bone, or light spots in those places where the tumor forms calcium deposits
with the formation of new bones (sclerosis).
A more sensitive method is
computed tomography. It allows you to detect very small "hot spots"
that cannot be seen on the radiograph. An even more informative method is
PET-CT. This study is prescribed in some cases:
to determine the stage of highly differentiated
sarcomas with unproven metastatic disease (Ewing's sarcoma, rhabdomyosarcoma,
leiomyosarcoma, osteosarcoma, malignant fibrous histiocytoma, synovial sarcoma
and myxoid lip sarcoma);
A biopsy is needed to make a
definitive diagnosis when sarcoma is suspected and primary tumors in other
organs are not detected. In secondary bone tumors, when the site of primary
tumor formation is known, a biopsy is usually not required. A puncture biopsy
is usually performed under local anesthesia.
All subsequent examinations are
performed to determine the spread of tumor cells (in the case of a secondary
tumor) or to identify the primary lesion. Such studies include, as a rule, CT
scan of the chest (there often metastasizes primary tumors of other organs), ultrasound
examination of the liver.
TREATMENT
With sarcomas, surgery is usually
performed. In the past, this was a major operation, including amputation of the
affected limb. In LISOD, in all cases, it is possible to remove only the
affected part of the bone and replace it with an implant made of quality
materials. In cases where there is a germination of tumor cells of the chest in
one or two parts of the lungs, these parts can be removed surgically, if the
patient is sufficiently compensated and able to undergo surgery.
Surgical treatment is also the
main method for secondary bone tumors (resection of metastases), especially if
they are single (1-2) and isolated, such as pulmonary metastases of sarcoma
(especially osteo- or chondrosarcoma).
For some types of primary bone
tumors, LISOD provides neoadjuvant therapy: this treatment is performed as an
adjunct to surgery, such as radiotherapy or chemotherapy. When surgery is not
possible, in some cases only radiotherapy or chemotherapy is used, such as
osteogenic sarcomas.
Chemotherapy is performed as a
form of adjuvant therapy after surgery in the case of osteogenic sarcomas and
is aimed at eliminating small metastases. We use Varian linear accelerators for
remote therapy. Individual planning, the presence of collimators that allow you
to create radiation fields according to the shape of the tumor, significantly
reduces the risk of side effects of radiation.
Neoadjuvant therapy is most often
used to reduce the size of the tumor to such an extent that gentle surgery can
be performed. In Ewing's sarcoma, the usual approach involves several cycles of
chemotherapy before surgery to reduce the size of the tumor and subsequent
surgery or radiotherapy, or both.
Most bone tumors, especially
secondary ones, activate cells (osteoclasts) that lead to bone destruction.
Drugs known as bisphosphonates usually have a very good effect, reducing the
activity of osteoclasts and thus slowing or weakening bone destruction.
SYMPTOMS
Malignant bone tumors, both
primary and secondary, are similar in their manifestations. They are
characterized by constant, deep and aching pain, independent of exercise. With
Ewing's sarcoma, the pain worsens at night; there is no relief, even if the
limb is fixed in a certain position.
If the malignant tumor has
already led to the fragility of the bones, the first symptom may be a fracture
as a result of even a slight fall.
Confusion and abdominal pain,
nausea and vomiting may occur. This happens when calcium salts get from the
bones into the blood. The level of calcium in the blood increases
(hypercalcemia).
RISK FACTORS
The causes of sarcoma are
currently being studied. There is evidence that people with Paget's disease
(inflammatory chronic bone disease) are at high risk (in adulthood or old age)
of developing osteogenic sarcoma. But this disease is observed in a small
number of people. Injuries and microtraumas under heavy loads can also be the
cause of the disease. As mentioned above, secondary tumors are metastases of
primary tumors that are in other organs. Secondary tumors can sometimes be a
sign of primary cancer that shows no symptoms.
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