Osteosarcoma can begin in any bone segment, but tends to develop more commonly in areas with a rapid growth rate. Often, the neoplastic process originates in the metaphyseal or terminal regions of long bones: in the tibia, in the femur (near of the knee) and in the humerus (in the upper arm). Other sites such as hip, pelvis, shoulder and jaw (especially in elderly patients) are not excluded.
The neoplastic process leads to the destruction of normal bone tissue. In some cases, the tumor can weaken the bone structure to the point of causing pathological fractures.
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The causes that lead to the onset of osteosarcoma are not yet known, but the characteristics of the disease have made it possible to identify some risk factors. Most cases begin sporadically, then appear in people who do not have a familial predisposition or other concomitant pathological conditions.
Osteosarcoma is probably caused by a combination of genetic alterations, which together result in the transformation of immature bone cells into tumors; instead of undergoing differentiation and organizing themselves to form healthy bone, these cells "go crazy" and begin to replicate quickly, subverting the normal bone structure. The specific alterations in the genes that induce the hyperactivity of these cells are still under study.
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Osteosarcoma Initial Symptoms
At the onset of the disease, the pain on the affected area may be intermittent and quite vague, and worsen at night or during physical activity and movement. However, over time, it tends to gradually become persistent and more severe.
The symptoms of osteosarcoma can mimic the pain caused by normal bone growth, with the difference that these tend to stop during the early teens. Sometimes, as the cancer progresses, other general symptoms such as fatigue, excessive sweating, back pain or a loss of bowel or bladder control (if the tumor is in the pelvis or at the base of the spine) occur. neoplastic mass grows and presses on nearby structures, the patient may feel a sensation of pressure: for example, if this compresses a nerve it can cause pain, tingling, muscle weakness or numbness. If the cancer spreads to other parts of the body, it can develop various other symptoms.
For further information: Specific Osteosarcoma Symptoms to diagnose an osteosarcoma and determine the presence of any metastases, even in regions other than that of tumor origin. These investigations can help determine the most suitable treatment. The diagnostic process usually begins with the acquisition of radiographic images of the suspect region (X-rays), continues with a combination of other imaging tests (computed tomography, PET, bone scan and magnetic resonance) and ends with a biopsy.
Imaging helps determine the presence and location of a tumor, and can determine if the osteosarcoma has given rise to metastases. The tumor is solid and irregular, due to the spicules of the calcified bones, which radiate to form right angles. This characteristic lesion of osteosarcoma, known as "Codman's triangle" is detectable by radiographic examination and highlights the raised periosteum due to the tumor. The surrounding tissues are infiltrated. Bone biopsy is the only method that allows to definitively confirm the presence of an osteosarcoma.
is a system that allows you to describe the position of the tumor and its possible extension to other parts of the body. This information, obtained with in-depth diagnostic tests, allows you to establish which type of treatment is best for the patient and helps to formulate a prognosis (i.e. to define the probability of recovery).Osteosarcoma can be defined as:
- Localized: if the cancer cells are located only in the bone tissue, where the tumor originated;
- Metastatic: if cancer cells have spread from bone to other parts of the body; usually, metastases affect the lungs or other bones.
- Relapsing: Osteosarcoma is relapsing if it has come back during or after treatment, in the same location as the original tumor or in another region of the body.
The chemotherapy regimen includes one or more courses before surgery (neoadjuvant chemotherapy), to reduce the size of the tumor and avoid the amputation of the arm or leg. The duration of treatment varies and may depend on whether or not the cancer has spread to other parts of the body. Once the patient completes the course of chemotherapy, surgery can be used to remove residual cancer tissue. After the surgical procedure, further courses (adjuvant chemotherapy) follow to destroy any remaining cancer cells, which may still be present in the body. The side effects of chemotherapy depend on the individual's response, the duration of treatment and the dose used, but can include fatigue, risk of infection, nausea and vomiting, hair loss and diarrhea. These immediate side effects usually disappear once once treatment is finished. Other consequences, such as decreased heart muscle strength, hearing loss, or decreased kidney function may persist over the long term.
Chemotherapy drug used
Potential long-term effect
Doxorubicin (Adriamycin)
Heart failure
Cisplatin
Loss of hearing
Ifosfamide
Infertility and kidney damage
Etoposide
Induced leukemia
Surgery
In most cases, surgeons are oriented towards conservative surgery. Often, the procedure involves surgical removal of the tumor and surrounding bone tissue (complete surgical resection). To help maintain function and give the limb (arm or leg) a more normal appearance, surgery can be completed with a bone graft, taken from another part of the patient's body or from a donor (allograft). , and with reconstructive surgery techniques. Alternatively, the diseased part of the bone can be replaced with a metal or other material prosthesis. Chemotherapy can be resumed after the surgical approach to destroy any remaining tumor cells and lower the risk of recurrence. Some complications, such as local tumor infections or relapses, may require further surgery or amputation (ie surgical removal of the limb. In the latter case, rehabilitation can help the patient cope with the effects of losing a limb.
Radiotherapy
Radiation therapy involves the destruction of cancer cells by high-energy radiation. In the management of osteosarcoma, this treatment is not very effective, but it can help reduce the size of the tumor before surgery, or control symptoms in the more advanced stages of the disease. A radiotherapy regimen consists of a certain number of treatments, carried out over a certain period of time. Side effects can include fatigue, mild skin reactions, upset stomach, and diarrhea.
After Osteosarcoma Treatment
After treatment, your doctor can establish a monitoring plan. This may include regular physical examinations and / or investigations to evaluate the patient's recovery and rule out the onset of tumor recurrence or delayed effects.
Potential complications
On some occasions, chemotherapy and surgery cannot completely cure osteosarcoma; as a result, cancer cells can continue to proliferate and migrate to other regions. When these approaches fail, or serious treatment-related complications arise (infections, rejection in case of allograft, etc.), the doctor may suggest amputation. If metastatic cells reach the lungs, signs may occur including: chest pain, dyspnoea, chronic cough, hemoptysis, and hoarseness.
Recurrence of Osteosarcoma
Remission consists of the temporary or permanent absence of evidence of disease; at this stage the tumor is asymptomatic and cannot be detected in the body.
However, osteosarcoma can recur even after the period of remission induced by the chemotherapy regimen and the surgical approach.
Treatment of osteosarcoma relapses depends on three factors:
- Time elapsed from the remission phase (relapses are rare after more than five years);
- Type of treatment the patient received for the original tumor;
- Health conditions of the patient.
Often the treatment plan will include the same therapies used previously to fight osteosarcoma (surgery and chemotherapy), but they can be used in a different combination or given at a different pace.
When relapsing osteosarcoma affects another bone or a small number of other bones, a surgical procedure may be performed, particularly if neoadjuvant chemotherapy has been found to be effective.
