What is radiotherapy?
- Radiotherapy may be applied for curative purposes, to treat the patient, or for palliative reasons, to treat metastases, especially in the brain, or to relieve pain from bone metastases. It is sometimes used alone, for example to treat some brain, lung or gynecological tumors that cannot be removed surgically. It is also regularly used in combination with surgery and drug treatments as part of a multidisciplinary approach. Radiotherapy can often help avoid disfiguring surgery and thus save the affected organ (breast, rectum, ENT organs).
Several types of radiation are possible.
- External radiotherapy is the most frequent form. It involves delivering an electron, photon or proton beam (protontherapy) via particle accelerator into the volume of the tumor.
- Brachytherapy involves putting radioactive sources in contact with or inside tumors, for more targeted treatment. It can be prescribed for certain prostate, gynecological, anal canal and eye cancers.
The main biological effect of ionizing radiation is to break the DNA strands of the tumor cells – either directly or through the formation of free radicals – which leads to the death of these cells.
Every radiation treatment requires a period of preparation, during which the specialist makes a precise calculation of the volumes to be irradiated based on scans performed in the treatment position, sometimes merged with MRI or PET-scan images. These images also make it possible to locate the healthy organs adjacent to the treated volume and to draw up a personalized treatment plan for each patient.
The precision of the treatment’s delivery and the quality controls implemented are crucial to ensuring the most effective results possible.
The estimated dosimetry is prepared by dosimetrists, checked by medical physicists and validated by radiotherapy oncologists. The treatment plan’s parameters are verified by the radiophysicist.
The positioning of the patient on the treatment table is carefully checked every day. The dose actually received is systematically measured and compared to the planned dose. Throughout treatment, a weekly medical consultation provides for strict medical follow-up.
Radiotherapy at Institut Curie
Institut Curie has 12 treatment devices: Seven in Paris, four in Saint-Cloud and one in Orsay.
Institut Curie’s practitioners can conduct radiotherapy for all types of cancer that require this kind of treatment. They have particular expertise in the treatment of breast cancers, children’s cancers and sarcomas. In pediatrics, the experts at Institut Curie administer treatments under general anesthesia.
The Institut’s modern equipment allows for several types of radiation to be performed.
- Conformal radiation and with intensity modulation.
- Rotational radiation by tomotherapy or volumetric arc therapy.
- Stereotaxis, i.e. multiple-beam convergence on a small volume. This requires identification via imaging and results in fewer sessions, since the doses are concentrated. This technique is used for brain, bone or pulmonary lesions.
- The cyclotron based at our Orsay site also allows for the practice of protontherapy. This technique is mainly used for the treatment of tumors of the eye, the base of the skull, and the spinal column, and for childhood tumors. The indications for protontherapy are still at the developmental stage. Institut Curie has been using protontherapy since 1991. Until recently, it was the only center to treat tumors other than eye tumors.
Research in radiotherapy
The Radiotherapy department is involved in several clinical and translational research projects with a variety of aims:
- To better understand the biological effects of the various types of ionizing radiation.
- To increase the effectiveness and tolerance of treatment within clinical trials.
- To take part in technological development and evaluate new treatment methods.
- To develop research into the drug treatments associated with radiotherapy to enhance its effectiveness.