Osteosarcoma (Latin osteosarcoma) is a malignant tumor that originates from bone tissue. Find out who most often develops osteosarcoma, what symptoms are osteosarcoma, what diagnostic tests should be performed when osteosarcoma is suspected, and how is osteosarcoma treated.
Contents:
- Osteosarcoma - introduction. Bone structure
- Osteosarcoma - risk factors
- Osteosarcoma - symptoms
- Osteosarcoma - diagnosis
- Osteosarcoma - classification. Progress
- Osteosarcoma - treatment
- Osteosarcoma - prognosis
Osteosarcoma( osteosarcoma , Latinosteosarcoma ) is most often diagnosed in young people , especially in adolescents in the period of intensive growth.
Although the incidence of osteosarcomas is relatively low (in the Polish population it is about 80 new cases a year), this group of cancers should not be underestimated.
In the case of unexplained ailments from the skeletal system, a possible neoplastic process should always be ruled out.
Treatment of osteosarcomas is usually aggressive and multidirectional, and an early diagnosis increases the chances of therapy success.
Osteosarcoma - introduction. Bone structure
Before we get into the description of osteosarcomas, let's take a brief look at the organs in which these tumors develop - the bones.
Due to the shape, there are several types of bones:
- long bones
- short bones
- flat bones
- various bones
Hearing the name "bone", most of us probably imagine a long bone. Examples of long bones in our body include
- humerus
- femur
- tibia
- ulna
Speaking of osteosarcomas, we will primarily focus on this group of bones.
It is estimated that as much as 80-90% of osteosarcomas develop in long bones.
There are 3 basic structures in the construction of the long bone: the proximal epiphysis, the shaft and the distal epiphysis. The roots of the long bones are coveredcartilage and form articular surfaces.
There are so-called sockets.
Within the epiphyses there is one more very important element: growth cartilage. Growth cartilage enables the bone to grow longitudinally. After the growth process is complete, this cartilage transforms into bone.
The set of long bones is the place where osteosarcomas most often develop.
Among them, the distal epiphysis of the femur and the proximal epiphysis of the tibia should be particularly distinguished, i.e. structures located in the immediate vicinity of the knee joint.
It is estimated that up to half of the osteosarcomas are located in the knee area.
Another relatively common location for these tumors is the humerus. Osteosarcomas located in the axial skeleton (skull, spine, pelvis) or in the small bones of the hands and feet are much less common.
Osteosarcoma - risk factors
There are several hypotheses regarding the causes of osteosarcomas. The specific factors behind the development of these tumors are still unknown.
In many patients, the formation of osteosarcomas seems to be associated with the so-called a growth jump, i.e. a rapid growth of bones in length. This relationship is both temporary (peak incidence in the second decade of life) and localization (osteosarcomas developing in the vicinity of growth cartilages).
Gender is an independent risk factor: osteosarcomas are more common in men (frequency 3: 2 compared to women).
In older patients, osteosarcomas may develop on the basis of pre-existing bone disease. I am talking primarily about various types of bone dysplasias, i.e. diseases related to the abnormal structure of the bone tissue.
Another risk factor is ionizing radiation: previously irradiated bones are at a higher risk of neoplastic processes. The risk increases with the dose of absorbed radiation.
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It is also known that genetic predisposition plays a certain role in the formation of osteosarcomas. So far, there are several known genes whose mutations may contribute to an increased risk of developing osteosarcoma.
Osteosarcoma - symptoms
The risk factors for the development of osteosarcomas mentioned in the previous section show how little we know about the formation of these neoplasms. They are also negligible as a resultpossibilities of osteosarcoma prophylaxis. For this reason, it is very important to follow the rules of the so-called oncological vigilance.
It is good to know what symptoms osteosarcoma can give and when it is absolutely necessary to deepen the diagnosis of this cancer.
- Bone pain
The first and most common symptom of osteosarcoma is bone pain. Ailments are usually localized in a specific place. A particularly disturbing symptom (called a "red flag" in oncology) is pain that occurs at night and wakes the patient up from sleep.
- Swelling of adjacent soft tissues
Another common symptom is swelling of adjacent soft tissues. In the case of a significant tumor advancement, it sometimes happens that the tumor is visible to the naked eye.
Unlike many other malignancies, osteosarcomas rarely cause general symptoms such as
- anemia
- low fever
- weight loss
- weakness
Sudden, severe bone pain may result from a pathological fracture, which is a consequence of the weakening of the bone structure by the cancer developing in it.
Osteosarcoma - diagnosis
The first stage in the diagnosis of osteosarcoma is a medical history and physical examination.
In order to visualize any changes in the bones, it is necessary to perform imaging tests.
The basic type of imaging is x-ray. The X-ray image in osteosarcomas is heterogeneous: the image may show both the points of bone tissue destruction and its build-up.
A characteristic symptom on X-ray pictures of osteosarcomas is the so-called Codman's triangle, i.e. elevation of the periosteum in the vicinity of the neoplastic infiltrate.
An X-ray image allows you to visualize the pathology, although a thorough assessment of its extent and degree of advancement requires additional research.
In order to better visualize the inside of the bones (medullary cavities), as well as the surrounding soft tissues, magnetic resonance imaging is performed.
The next stage of diagnostics is to detect possible metastatic foci.
Osteosarcoma is a malignant neoplasm that can metastasize through the bloodstream.
It is estimated that at diagnosis, approximately 15% of patients have metastases visible on imaging tests.
Osteosarcoma has a tendency to metastasize within the lungs, so an X-ray or CT scan of the chest should also be done.
Also, the diagnosis of osteosarcoma isan indication for a scintigraphic examination of the whole skeleton. Scintigraphy makes it possible to visualize tumor foci located in other bones.
Although imaging tests often suspect the malignancy of the lesion, the final diagnosis is possible only after histopathological verification. To perform a histopathological examination, it is necessary to take a sample of the tissue affected by the disease.
Such a section is obtained during a bone biopsy. The pathologist subject the obtained material to a special treatment and then examines it under a microscope. The result of the histopathological examination allows to establish the diagnosis and classify the neoplasm according to its type and stage.
Osteosarcoma - classification. Progress
Osteosarcomas can be classified according to various criteria. The first type of assessment is the histological grade of the neoplasm, called grading.
Grading answers the question of how intensified the malignancy features are in the cells of the tumor under study.
The grading scale for osteosarcomas has four grades (from G1 to G4), with G1 being low-grade, G2 being medium, and G3 and G4 being high. Examples of osteosarcomas belonging to particular groups are:
- G1 - osteosarcoma
- G2 - extraosarcoma
- G3 and G4 - classical, angiosarcoma, small cell osteosarcoma
The second important component of the assessment of osteosarcomas is the clinical stage, the so-called staging.
As in the case of many other malignant neoplasms, the TNM classification is used to assess the clinical stage, based on three basic features of the tumor: the size of the primary tumor (T - tumor), the presence of metastases in the local lymph nodes (N - nodes) and the presence of distant metastases (M - metastases).
Staging osteosarcomas is represented by the following symbols:
I. Feature T (tumor size):
- T0 - no primary focus
- T1 - primary focus greater than or equal to 8 cm (in the maximum dimension)
- T2 - primary focus larger than 8 cm (in maximum dimension)
- T3 - other tumor lesions within the same bone
II. Feature N (nearby lymph nodes):
- N0 - no metastases in the local lymph nodes
- N1 - present metastases in the local lymph nodes
III. Feature M (distant metastases):
- M0 - no distant metastasis
- M1 - current distant metastases
Osteosarcoma-treatment
Treatment of osteosarcoma is combined: both tumor removal surgery and additional pharmacological treatment (chemotherapy) are important.
Radiotherapy in the treatment of this group of neoplasms shows little effectiveness.
The basic stage of osteosarcoma treatment is a surgical procedure consisting in the complete removal of the tumor with an appropriate margin of he althy tissue.
In the past, the diagnosis of osteosarcoma often required limb amputation. Nowadays, thanks to the advances in reconstructive surgery techniques, it is usually possible to perform less radical procedures that save the limb.
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The treatment regimen for osteosarcoma also includes two stages of chemotherapy: neoadjuvant and adjuvant.
- Neoadjuvant chemotherapy
Neoadjuvant chemotherapy is administered before surgery and allows the tumor size to be limited, thus facilitating its excision. A good response to preoperative chemotherapy is also a favorable prognostic factor.
- Adjuvant chemotherapy
Adjuvant chemotherapy is administered after tumor resection surgery. The main purpose of its use is to destroy the so-called micrometastases, that is, residual tumor cells that remain in the body despite the removal of the main tumor mass.
In osteosarcoma chemotherapy, several drugs are usually used in combination. The most commonly used are:
- doxorubicin
- cisplatin
- ifosfamid
- etoposide
- methotrexate
Multi-drug therapycarries a high risk of side effects, therefore patients undergoing chemotherapy should be constantly monitored for the functions of internal organs (liver, kidneys, heart), as well as infectious complications caused by impaired blood cell production by the bone marrow.
Osteosarcoma - prognosis
The prognosis of osteosarcoma depends on many factors, however, the stage of the cancer at diagnosis is of major importance.
If the disease is detected in a limited stage, before the onset of metastases to the lymph nodes or distant organs, the prognosis is much better.
Currently used therapy scheme:
- preoperative chemotherapy
- surgery
- postoperative chemotherapy
allows you to get the 5-year survival rate within limits60-70%.
Worse prognosis applies to osteosarcoma in the metastatic stage, as well as cases of recurrence of this tumor.
About the author
Krzysztof BialaziteA medical student at Collegium Medicum in Krakow, slowly entering the world of constant challenges of the doctor's work. She is particularly interested in gynecology and obstetrics, paediatrics and lifestyle medicine. A lover of foreign languages, travel and mountain hiking.
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