Sarcoma treatments

The treatment of sarcomas of soft tissues and bones when they are localized is primarily based on surgery. However, sarcomas can evolve in various manners, slowly or very quickly, with risk of metastases (like Ewing's sarcoma) or not (for example, liposarcoma). This is why surgery is sometimes supplemented with chemotherapy and/or radiotherapy, depending on the type of sarcoma, its stage, its location, and the results of the surgery. The treatment choices are decided upon in a multidisciplinary consultation meeting.

Sarcoma surgery

The quality of surgery is fundamental to the survival of sarcoma patients. Institut Curie has shown that the management of patients in an expert center improves the prognosis of patients. 
The surgery consists of removing the tumor with the necessary amount of surrounding tissue in order to avoid a risk of local recurrence. What makes Institut Curie unique is that its teams have expert sarcoma surgeons. It is also a national and international referral center for abdominal sarcomas, the world's third largest center in the field. In addition, plastic surgeons from Institut Curie collaborate in certain cases in order to provide patients with reconstructive surgical options.
This type of sarcoma surgery is particularly challenging for several reasons:

• Under no circumstances should the tumor be opened. Otherwise, there is a risk that cancer cells will spread throughout the body.
• The width of the margin of healthy tissue removed with the tumor must be adapted to each specific case.
• Surgery can involve several organs, while being performed jointly.
• The articular, muscular, and organic functions must be preserved as much as possible.
• Reconstructions may be necessary.

Chemotherapy for sarcomas

Chemotherapy is not routinely used in the treatment of sarcomas. The protocol is decided by the medical team, as part of a multidisciplinary consultation meeting, depending on the type, grade and stage of the sarcoma, as well as the patient's state of health.
If the tumor size has to be reduced, chemotherapy can be used prior to surgery. This is often the case for children's sarcomas and is done in order to facilitate the surgical procedure. It is also possible to perform an "isolated limb perfusion" for chemotherapy. This technique involves isolating an arm or a leg affected by a sarcoma from the bloodstream using a tourniquet and extracorporeal circulation. It makes it possible to deliver higher doses of anticancer drugs to the patient than if they were administered systemically.
Chemotherapy can also be administered following surgery in order to avoid relapses, in case the disease has caused metastases. Doxorubicin is the anti-cancer drug that is most often used in sarcomas. In the cases of soft-tissue sarcomas, this molecule is sometimes associated with ifosfamide, dacarbazine or trabectedine.
In osteosarcoma, it is combined with cisplatin and methotrexate.
In Ewing sarcoma and sarcoma of the joints (chrondosarcoma), several other medications are combined with doxorubicin, such as cyclophosphamide or ifosfamide. Immunotherapy or targeted monoclonal antibodies may be combined with chemotherapy.
Institut Curie is also investigating new drug treatments based on the metabolism of iron in cancer cells, which would play a key role in the proliferation of sarcomas.

Sarcoma immunotherapy

Immunotherapy is still seldom used in the treatment of sarcoma, except in very rare cases. New therapeutic approaches are currently being evaluated for these tumors, which do not respond well to immunotherapies traditionally effective in other types of cancer. Institut Curie has also highlighted the expression of highly specific genes in Ewing's sarcoma and some other pediatric sarcomas, which suggests the possibility of immunotherapies targeting tumor-specific proteins.

Targeted therapy of sarcomas

Certain sarcomas are associated with specific molecular abnormalities, which can then serve as therapeutic targets. 
The best known example is that of the gastrointestinal stromal tumors (GISTS) that are treated with gene-targeting therapies KIT or PDGFRA like Imatinib. 
Some sarcomas that mainly affect very young children are associated with fusions of the NTRK gene. The development of NTRK receptor blockers (such as Larotrectinib) has made it possible to obtain spectacular results in these patients.