Radiotherapy is a localised treatment, in which high-energy rays are delivered to a precise zone of the body, hosting the disease, preserving the normal surrounding tissue as much as possible.


Radiotherapy is especially used to treat Hodgkin lymphomas. The devices used are called “accelerators” or “cobalt” devices, depending on the type of rays that are emitted. Receiving these rays never causes lingering radioactivity.


Radiotherapy is usually performed once a day, every day except for the weekend. Its duration can vary from 1 to 4 weeks, depending on the case. The treatment intervals and duration, determined by the radiotherapist, must be observed.


The first “centering” meeting aims to precisely define the area to be irradiated, the zones to be protected and the irradiation technique that is the most adapted to each patient. To this purpose, radiological images are taken thanks to a “simulator”, a device with the same technical characteristics as the future treatment device. The zone to be irradiated will be marked with a pen on the skin (not to be erased) or with little tattoo marks, of the size of a pen tip (these tattoo marks remain permanently). This planning stage lasts from 40 to 60 minutes, and the treatment itself will only start several days later, as a certain amount of calculations are necessary. To define even more precisely the areas to be irradiated and those to be avoided, a “scanner radiotherapy” may be proposed, before, during or after the centering.

As of the first radiotherapy session, the patient will meet the team of technicians who will administer the treatment every day. A monitoring image will be taken, validated by the radiotherapist doctor. The patient is installed by the technician(s), who will then leave the room, while remaining in contact through an interphone and a video recorder. The entire session lasts for less than 15 minutes.

A periodic monitoring consultation will be held with the radiotherapist during the treatment, usually once a week. The irradiation usually does not require hospitalisation.


Radiography can have short, medium and long-term side-effects. Their occurrence is monitored by the medical team. In case of doubts, there should be no hesitation at asking any questions of the technicians and radiotherapist doctor.


The side-effects occur as of the second half of the treatment, and recede over the course of several weeks after the end of the treatment. They are limited to the irradiated area, as radiotherapy is a localised treatment.

For example, radiotherapy in the throat area, irradiating the salivary glands, modifies the quality and quantity of saliva in the mouth. The mouth then becomes dry and sensitive: it can become more and more difficult to chew and swallow. As saliva protects the teeth, the dryness in the mouth can accelerate the development of cavities and gingivitis. Particular treatments are then recommended. In certain cases, the irradiated tongue becomes “hypersensitive”, and the taste of food may change for a long stretch of time before slowly going back to normal.

If the throat or thorax areas are irradiated, this may cause an inflammation which manifests itself as a sore throat, present at a lower sport than throat infections. After several weeks of irradiation, burning feelings occur behind the throat and the sternum. During this period, acid, dry or irritating food should be avoided, and semi-liquid, tepid meals should be favoured. If the larynx is included in the irradiated zone, the patient’s voice may weaken, be sensitive to climatic variation or change its timbre for several weeks. Rays to the thorax can trigger a persistent dry cough.

Other examples can be named. Radiotherapy on the skull can cause headaches and general tiredness. Radiotherapy on the abdominal area can cause bouts of nausea or diarrhoea.

More generally, in the irradiated area and after several weeks of treatment, a “sunburn-like” reaction can appear, with the skin becoming dry and more sensitive. In the months following the end of the treatment, a discrete cutaneous pigmentation can persist, similar to a sun-tan. The hair in the irradiated areas may fall out. All these phenomena slowly correct themselves after the end of the radiotherapy.

A suitable nutrition and medicines that are effective against all these uncomfortable effects will be prescribed in the weekly consultations. As to the effect of the rays on the skin, some local hygiene precautions are to be followed for the duration of the irradiation in order to prevent or limit these effects, such as:

  • avoiding showers and baths that are too hot;
  • leaving the irradiated areas uncovered as much as possible, without soaping them, but letting the soapy water run across them;
  • using basic Marseille soap (or the product prescribed by your doctor), but never alcohol, eau de toilette, deodorants, talc or cream on the irradiated areas;
  • drying without rubbing;
  • wearing ample, cotton clothes, avoiding friction.

In the longer term, certain complications, particularly cardiac, digestive or lung complications, may occur several years after the radiotherapy. This fully justifies the continuation of the medical monitoring, well after the end of the treatment.

For more information, a full booklet called “Better understanding radiotherapy” can be provided, either by the oncology and radiotherapy specialist, or directly by the Ligue Nationale Contre le Cancer (the French national league against cancer)