Sarcomas

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Sarcomas are rare malignancies affecting around 5 in 100,000 people every year. They originate in connective tissues, that is to say, the tissues in charge of supporting the body, and can, therefore, affect muscles, bones, cartilage, tendons, deep skin layers, blood vessels and adipose tissue. 

Currently there are over 100 different types of sarcomas known, divided into 3 macro-categories:

• Bone sarcomas
• Soft-tissue sarcomas
• Gastrointestinal stromal tumours

In this context we deal with bone sarcomas.

Bone sarcomas: osteosarcoma and chondrosarcoma

What are they?
Bone sarcomas are primary tumours of the bone, that is, tumours that arise in the bone itself; they are less frequent than metastatic bone tumours, which arise after cancer cells migrate from other parts of the body, affecting 1 person per 100,000 on average each year. This disease most commonly affects young adults around 20 years old; in any case, more than half of the diagnoses occur before the age of 60.

Which is the onset location? 
Potentially, a primary bone tumour can originate from any bone segment.  In young people, bones that grow rapidly (such as the long bones of the legs or arms) are generally most often affected, whereas in the elderly, the bones most affected include shoulder blades, jaw or knee.

How are they classified?
Depending on their cellular origin, bone sarcomas are divided into:

• Osteosarcoma: the most frequent primary bone tumour; it develops in the bone tissue
• Chondrosarcoma: the second most frequent primary bone tumour; it develops in the cartilage

Osteosarcoma originates from osteoblasts precursors, which are special cells making up a bone that cannot evolve into a mature cell and so remain in an immature and precancerous state. It generally arises in the period of maximum bone growth and therefore, mainly affects children and adolescents, without major differences between boys and girls.

Chondrosarcoma originates in the cartilage, a connective tissue that, besides providing support, contributes to the formation of bones.
It arises more in men than in women and it most commonly affects the femur, humerus, scapula, pelvis and ribs. There are different types that can be classified according to the cell that forms the tumour (clear-cell, de-differentiated, mesenchymal or conventional chondrosarcoma) or according to how aggressive the malignancy is (I°, II° or III°).

Symptoms of sarcomas

Symptoms of bone sarcomas may not be hidden for a long time and when they appear, depending on the tumour location, they are mainly the following:  

• Pain, swelling, redness
• Joint stiffness, lameness
• Limitation of motion
• Pathologic fractures

In the onset of osteosarcomas, pain can be intermittent and vague, but tends to intensify at night and during exercise. As the disease progresses, pain becomes constant and severe.

When the tumour grows, other symptoms sometimes appear, such as fatigue, excessive sweating, back pain or incontinence of bowel and/or bladder (if tumour affects the pelvis or the base of the spine). 

In general, if a sarcoma spreads to other parts of the body, various other symptoms may develop.

Diagnosis of sarcomas

Fractures, infections and many other conditions can mimic the presence of a bone tumour and this makes diagnosis complex.

To determine the existence of a bone sarcoma, physicians may request: 

• a detailed medical history
• an accurate physical examination (the set of diagnostic manoeuvres)
• blood tests and urinalysis
• diagnostic imaging tests, which are mainly used to identify the exact position and extent of the tumour mass
  • Nuclear magnetic resonance (NMR)
  • CT scanning (Computed Axial Tomography);
  • PET (Positron-emission tomography);
• a tumour biopsy, which consists in removing and analysing a sample of cells from the tumour. This exam identifies the specific type of sarcoma. A sample can be taken with a needle (needle bone biopsy) or a scalpel (‘open’ biopsy)

Treatment of sarcomas

Since these are rare diseases, the patient diagnosed with sarcoma should be evaluated and treated at the National Reference Centres with proven experience in this field.
Sarcomas are always treated with a multidisciplinary and comprehensive approach, involving the joint work of different specialists such oncologists, surgeons and radiotherapists. 

Surgery is considered to be the main option to treat sarcomas so that a total removal of the tumour is achieved 'with wide margins'. When the surgeon evaluates that the neoplasm is not operable in a conservative way, hadrontherapy with protons or carbon ions can be a valid alternative to X-ray radiotherapy.
In fact, a very high dose of rays can be irradiate that is not so harmful to the surrounding tissues.

Hadrontherapy can also play a role before surgery (neoadjuvant intent) or after surgery (adjuvant intent). 
At CNAO, we treat the following cases with hadrontherapy:

• Head and neck sarcomas
• Torso sarcomas
• Abdomen sarcomas
• Pelvis sarcomas
• Limb sarcomas (only selected cases)

The data gathered at CNAO show that hadrontherapy is very well tolerated, and in this way it completes the surgeon's work while being less toxic than traditional radiotherapy.