Radiotherapy at Institut Curie

What is radiotherapy?

Radiotherapy is a locoregional anticancer treatment that is based on irradiating cancer cells in order to destroy them. It can be curative, to cure cancer, or palliative, to slow down the progression of the tumor, relieve symptoms, and improve the quality of life.

Two thirds of patients with cancer will be treated with radiotherapy at some point of their course of care. Radiotherapy can be used as the only form of treatment, but it is most often combined with chemotherapy and/or surgery. For certain cancers, radiotherapy can be an alternative to surgery, or it can be used to complement it to reduce its scope, and thus preserve the affected organ (prostate, breast, rectum, bladder, etc/).

Institut Curie is the cradle of radiotherapy, which stemmed from Marie Curie's discoveries, and it boasts the most complete radiotherapy technical platform in Europe.

There are different types of radiotherapy, depending on the external or internal positioning of the irradiation source:

External radiotherapy

External radiotherapy is the most frequent form. The rays are emitted by a machine called a linear particle accelerator, which is placed near the patient who is lying on a table. The irradiation beams are directed specifically at the area where the tumor is located. They pass through the skin to reach the tumor. The rays can be of two types - photons or protons (protontherapy). Superficial irradiation of skin tumors can also be achieved with electrons (contact therapy).

Curietherapy

Curietherapy involves introducing a radioactive source inside the body to put it in direct contact with the tumor, which allows for a more targeted treatment. It may be indicated for localized cancers affecting accessible organs (gynecological and prostate cancers).

Vectorized internal radiotherapy

A type of irradiation that is burgeoning in nuclear medicine departments, metabolic radiotherapy, and vectorized internal radiotherapy, involves administering radioactive sources orally or by intravenous infusion.

Institut Curie's expertise in radiotherapy

With 15 treatment rooms (6 in Paris, 5 in Saint-Cloud, and 4 in Orsay), Institut Curie has the most complete radiotherapy technical platform in Europe. All types of radiotherapy are practiced there. Over 97,000 radiotherapy sessions are performed every year at the institute.

Conformal radiotherapy with intensity modulation, delivered by rotational dynamic arc therapy (VMAT)

This is the most widely used radiotherapy technique. It is coupled with image-guided radiotherapy, which makes it possible to check the positioning of the tumor before and during each irradiation session. It can also be combined with respiratory-dependent radiotherapy whenever it is necessary to take into account the movements of the tumor linked to respiration during irradiation.

Stereotactic radiotherapy

This very high-precision radiotherapy technique is increasingly preferred for treating localized cancers. By converging multiple beams on a small volume, it makes it possible to irradiate the tumor at a high dose while limiting the irradiation area in order to spare the surrounding healthy tissues. Institut Curie has many devices for performing this type of radiotherapy. Thanks to stereotaxy, it is now possible to treat with radiotherapy cancers that were previously resistant to this treatment (kidney, liver, pancreas, etc.).

MRI (magnetic resonance imaging) radiotherapy

This type of radiotherapy, which revolutionizes patient care, complements stereotaxy. It involves coupling an MRI (and no longer a conventional X-ray imaging) to a particle accelerator, making it possible to "track" with even more precision the changes in position or volume of the tumor during the entire irradiation session. This has the effect of targeting the area to be irradiated with even more precision and of reinforcing the effectiveness of the irradiation on the tumor. At Institut Curie, the MRI-Linac of the Elekta brand makes it possible for us to offer this type of radiotherapy routinely at the Saint-Cloud site for certain selected cancers.

Curietherapy

In addition to its external radiotherapy treatment rooms, Institut Curie has two pulsed-flow curietherapy projectors and a high-flow curietherapy projector that are used to treat gynecological cancers. It also offers curietherapy with permanent iodine-125 implants to treat prostate cancers, and it is the only center in France and one of the few in the world to practice ophthalmic curietherapy with iodine-125 discs.

Protontherapy

This ultra-precise technology is particularly indicated for treating certain tumors in children and adults, such as tumors of the eye. Institut Curie has one of the only protontherapy centers in France, which is located in Orsay.

Radiotherapy treatment

The first step in the external radiotherapy journey is a consultation with a radiotherapist oncologist. After that a scanner is placed on the treatment location to collect the patient's anatomical data and to trace on their skin reference points, which will be used to reposition them identically during the irradiation sessions. A delay of a few days, the exact duration of which varies depending on the complexity or urgency of the treatment, is then required prior to the start of the treatment.

During this phase, the radiotherapist oncologist, physicist, and dosimetrist work together to determine the volume that must be irradiated and the areas that must be protected (contouring). They also define the types of rays to be used, the dose of radiotherapy to be administered, as well as its distribution at the level of the tumor area (dosimetry). The objective of this step is to optimize the irradiation in order to treat the tumor as efficiently as possible while sparing the neighboring healthy tissues as much as possible. Once the personalized treatment plan has been established, the treatment schedule is communicated to the patient, and the irradiation sessions can begin.

A simplified course of care

Thanks to technological developments, and in particular stereotaxy, fewer and fewer irradiation sessions are now necessary during a radiotherapy treatment. Certain more precise particle accelerators, which are available on all Institut Curie sites (Paris, Saint-Cloud and Orsay), are equipped to allow treatments to be administered over one or two weeks (1 to 6 sessions) instead of five to eight weeks (25 to 40 sessions).

In addition to simplifying the patient's course of care, these more precise technologies better protect healthy tissues located near the tumor, thus limiting possible side effects. Moreover, thanks to these advances, Institut Curie has developed expertise to offer radiotherapy in the event of a second cancer or recurrence in an area that was already irradiated (re-irradiation).

Side effects of radiotherapy

Radiotherapy is likely to cause side effects. Acute side effects, which may occur after a few sessions, are temporary. Medical follow-up during radiotherapy and the prescription of care or appropriate treatment most often make it possible for patients to tolerate them. They usually resolve gradually within a few weeks. Late side effects, on the other hand, can appear several months or years after the treatments. Fortunately, these effects are very rare.

The techniques used at Institut Curie - and the advances in radiotherapy that make it possible to protect healthy tissues as much as possible - reduce these side effects or even succeed in making them disappear.

Dynamic research in radiotherapy

The cutting-edge research conducted at Institut Curie paves the way for innovative treatments in radiotherapy. In particular, researchers are currently working on a new class of drugs from the institute's laboratories, Dbait, which by strengthening the effectiveness of radiotherapy would make it possible to treat certain tumors that are currently radioresistant.

Mini-proton beam radiotherapy (pMBRT), which is based on a strong spatial modulation of the dose and alternating regions of high and low doses (thus making it possible to escalate the dose in the tumor), also raises many hopes for the treatment of radioresistant tumors.

Flash radiotherapy, a radiotherapy technique discovered in the laboratories of Institut Curie in the early 2000s, which involves administering a high dose of radiation in a fraction of a second, is also very promising.

In addition, several clinical research procedures are available to patients treated at Institut Curie for various cancers (prostate, bladder, breast, lung, brain tumors, etc.).