In Germany, around 150-200 people are diagnosed with bone cancer every year. A distinction must be made here between osteosarcoma, Ewing's sarcoma and chondrosarcoma.

Osteosarcoma

Osteosarcoma is a malignant mesenchymal tumour that grows into the bone marrow and forms bone substance (osteoid). At around 45%, it is the most common bone tumour. The disease peaks in 60% of patients between the ages of 10 and 25. Men are affected slightly more frequently than women. Approximately 30% of osteosarcomas occur in patients over the age of 40.

The long tubular bones are most frequently affected, especially the lower part of the femur, the upper part of the tibia and the humerus. Around 15-20% of the flat bones such as the pelvis and spine are affected and, in very rare cases, the facial skull. Infestation of the skull occurs predominantly in older people and has a less aggressive course than in other localisations. In approx. 15-20% of patients, metastases, particularly in the lungs, have already spread at the time of initial diagnosis.

Ewing's sarcoma

Ewing's sarcoma is a malignant tumour that primarily arises from bone tissue, although it can also occur outside the bone. Ewing's sarcoma accounts for approx. 10-15% of all bone tumours and 2% of all malignant tumours in children. In 80% of all Ewing sarcomas, a chromosomal alteration of chromosome 22 can be detected. Ewing's sarcoma occurs in young people between the ages of 3 and 30. The most common localisations are the thigh, pelvis, fibula, tibia and upper arm (decreasing from 20.8% to 10.6% of all cases). In approx. 20% of patients, metastases already exist at the time of initial diagnosis.

Chondrosarcoma

Chondrosarcoma is a cartilage-forming tumour and accounts for approx. 10% of all bone tumours. The majority of patients are between 40 and 60 years old.
Approximately 70% of chondrosarcomas occur in the pelvis, followed by the trunk, shoulder girdle, upper part of the thigh and upper arm.

The causes for the development of bone cancer are not clear. However, it is known that patients with Paget's disease, Li-Fraumeni syndrome (germline alteration) and a hereditary retinoblastoma (malignant retinal tumour of the eye) have an increased risk of developing osteosarcoma. A tendency towards bone tumours has been observed in patients who have already undergone radiotherapy or chemotherapy.

In 80% of patients with a Ewing bone tumour, a change in chromosome 22 was detected.

Chondrosarcomas can develop from benign chondromas (tumours of cartilage tissue) or exostoses (increased formation of bone substance - bumpy, spur-like bone protrusions).

Bone cancer does not cause any symptoms in the early stages of the disease.

Bone pain that occurs regardless of any strain on the bone is a possible indication of tumour disease. Bone tumours that are not localised on the arms and legs can grow unnoticed for a long time.

If bone cancer is suspected, various examination procedures are necessary in order to make an accurate diagnosis. These include, for example, a physical examination, laboratory tests, X-ray examination, ultrasound examination and computerised tomography (CT). Additional examinations such as magnetic resonance imaging (MRI), skeletal scintigraphy or positron emission tomography (PET-CT) may also be required.

Medical history and physical examination

During a detailed consultation, you will tell the doctor about all your symptoms and previous illnesses (including family hereditary diseases). You will then undergo a thorough physical examination.

X-ray examination

The X-ray examination is used to detect the bone tumour and/or to rule out lung metastases.

Sonography (ultrasound examination)

Sonography is a painless and radiation-free examination to detect bone cancer and/or metastases. In principle, the spread of the tumour to other organs or existing metastases (tumour metastases), e.g. in the liver, can be detected.

Computed tomography (CT)

Computed tomography is a special X-ray examination (with contrast medium) that scans the body layer by layer and can therefore show the exact location and size of the tumour.

Magnetic resonance imaging (MRI)

MRI is not an X-ray examination, but is based on magnetic field effects. Cross-sectional images are produced after the administration of a contrast medium, whereby mainly soft tissue parts of a tumour are shown.

Skeletal scintigraphy (bone scintigraphy)

By administering a small amount of radioactive substance into the bloodstream, tumour metastases in the bones can be visualised. A special camera recognises the radioactively enriched areas in the diseased bone. This is a gentle examination in which the radiation decays quickly.

Biopsies (tissue samples)

The tissue sample is necessary in order to classify the tumour (tumour classification), i.e. to identify the tumour subtype, the degree of malignancy and the characteristics of the tumour in order to enable targeted tumour therapy. The tissue sample must be taken at a centre specialising in sarcomas due to the risk of tumour cell spread and the planning of subsequent surgical removal of the tumour.

PET and PET/CT

PET/CT is the most modern fusion imaging technique, in which the anatomically high-resolution imaging of multi-line spiral CT is combined with the specific molecular imaging of PET in a single examination. This allows, for example, whole-body examinations for staging malignant tumours to be carried out in a single examination in approx. 30 minutes. Highly detailed imaging of the anatomical body structures with contrast-enhanced spiral CT and specific "staining" of pathological tissue changes with suitable molecular probes in PET are combined in an imaging diagnosis. Intravenous injection of a radiopharmaceutical is necessary for the PET examination. A drug similar to glucose (2-F-18 fluorodeoxyglucose FDG) is most commonly used.

In order to be able to determine the most suitable therapy, it is necessary to determine exactly which histological subtype (tissue type) the bone cancer corresponds to, what degree of differentiation (grading) it has and how far it has already spread. In other words, the tumour stage is determined. Grading and the TNM classification are used for this purpose (see tables below).

- Fine tissue subtype

Osteosarcoma, chondrosarcoma, Ewing's sarcoma

- Grading

Microscopic examination of the tumour tissue provides an indication of the malignancy of the tumour. This involves comparing the similarity of the cancer cells with the organ cells.

-TNM classification (2010)

Tumour spread is determined by the TNM classification.

T stands for the size and extent of the primary tumour, N stands for the number of affected regional lymph nodes and M stands for the occurrence and localisation of distant metastases (tumour metastases).

No distant metastases

The treatment methods depend on the type of tumour, tumour stage, age and general condition. The earlier a bone tumour is detected, the better the prognosis for the patient. In principle, it is safest for patients with a bone tumour to have these tumour-specific therapies carried out by specialist doctors at a centre within "clinical trials". A combination of surgery and systemic therapy (chemotherapy) is usually required.

Treatment of osteosarcoma

The most promising therapy is provided by the international EURAMOS 1 study, which is based on the results of 25 years of continuous study activity by the Cooperative Osteosarcoma Study Group (COSS). The study is currently closed to new admissions and has been analysed since the end of 2011; initial results were published in 2015. New patients are reported as registry patients and treated exactly according to the study specifications. This treatment procedure represents the standard therapy. Children, adolescents and young adults under the age of 40 should be treated analogue to the study.

The EURAMOS 1 study comprises several different treatment methods in succession. Once the histological diagnosis has been confirmed by a biopsy, preoperative chemotherapy with four different cytostatic drugs is used to shrink the tumour. In the 10th week, the tumour is completely removed with a safety margin. The radical nature of the operation depends on the size and location of the tumour. Thanks to improvements in surgical techniques and prosthetic replacements, it is now largely possible to preserve extremities. Bone tumours that are not located on the extremities are more difficult for surgeons to access. However, even if a more radical surgical method has to be chosen, various reconstruction procedures are available.

This is followed by several weeks of post-operative chemotherapy. By combining chemotherapy and surgery, 5-year survival rates can be achieved in over 50-75% of cases. Surgery alone only achieves a cure in a maximum of 20% of patients.

Patients over the age of 40 are to be treated in the European EURO-B.O.S.S. study. This treatment procedure also represents the standard therapy and is essentially similar to the EURAMOS study, but with less highly administered and therefore age-adapted chemotherapy. The study also includes chemotherapy before and after surgery as well as surgical removal of the tumour.

Metastases are surgically removed where possible.

Radiotherapy for osteosarcoma

Radiotherapy is used for osteosarcoma to relieve pain or in cases of inoperability (e.g. of the skull or pelvis).

Treatment of Ewing's sarcoma

Ewing's sarcoma also requires a combination of different treatment methods in order to prolong survival times. The international EWING 2008 study is a therapy concept based on more than 20 years of research. It involves a combination of chemotherapy, surgery and radiotherapy. The combination of these different therapies results in a significant improvement in prognosis. Depending on the size of the tumour, 10-year survival rates (cure) of 50-75% can be achieved.
Individual partial study results will be published in 2016.

Treatment of chondrosarcoma

The optimal removal of the tumour is crucial for the patient's prognosis. If the tumour is completely removed, a cure rate of 40-60% can be expected if there is no additional tumour metastasis in other organs. In individual cases, with locally advanced tumours that are highly malignant, chemotherapy and radiotherapy can also be administered.

For all patients who are treated as part of the bone sarcoma studies, there is a precisely defined follow-up programme (initially every 6-8 weeks, then longer intervals) with clinical examinations, imaging procedures (X-ray/MRI/CT) and blood tests. These checks by surgeons and oncologists are carried out over a period of 5 years, after which an annual visit to the family doctor is recommended in order to detect possible late effects of the treatment.

Depending on the surgical procedure and the tumour prostheses used, follow-up treatment is initiated during the inpatient stay, often followed by further necessary physical treatment at home.

Depending on the patient's previous occupation, this can be resumed after the end of treatment, and counselling by qualified social service staff should take place at an early stage.

Main source:
Interdisciplinary guidelines of the German Cancer Society (AWMF - Association of the Scientific Medical Societies in Germany)