The device compacts in one morning the preparation times which could be spread over 2 to 3 weeks. How is it possible ?
Dr. Sofia Rivera: Indeed, the first morning is devoted to preparatory work and you can follow up directly with the first ray session right after. This is a huge time saving, feasible thanks to the commitment of the entire department and a reorganization at all levels. Because the teams must be available at the right time.
It is also achievable thanks to technological advances and artificial intelligence. This, for example, is used to reduce the time spent by caregivers on tedious and time-consuming tasks such as contouring (which consists of locating the volumes to be treated), the semi-automation of the dosage set up by our teams of physicists, for its part, is accelerating dosimetry.
Do we lose precision by going through the machines?
Dr. Sofia Rivera: Not at all, on the contrary. The machine does not replace humans, it saves time and efficiency, because the parameters are so fine that the margins of error are considerably reduced. The doctors intervene to validate; the skills of each – carer and machine – are used optimally.
Do we not lose efficiency either?
Dr. Sofia Rivera: No, for several reasons. This radiotherapy is hypofractionated, but in the end the biological dose of rays is equivalent to traditional protocols. It is a personalized approach (the doses are calculated as closely as possible to the needs of the patient), but also very targeted, because the guidance of the radiotherapy by integrated scanner – another innovation included in the device – increases the precision of the action. .
Fewer sessions therefore mean higher doses per session, and more side effects perhaps?
Dr. Sofia Rivera: Clinical trials have shown that there were overall fewer side effects with this device, including less fatigue. No more burning or irritation is seen, as these side effects are related to the total dose – which remains the same – rather than the dose per session.
This device is intended only for localized breast cancers without lymph node involvement, ie approximately 50% of breast cancers. Why ?
Dr. Sofia Rivera: Because the studies on the effectiveness of shorter radiotherapy took this type of cancer into account. We based our program on the results of two English randomized protocols, for which we therefore have scientific proof of efficacy: our device does not increase the risk of relapse and achieves the same survival rate as with five-week radiotherapy. Other clinical studies are underway, in Canada and India in particular, to test this protocol on breast cancer with lymph node involvement. We will have more visibility on that in a few years.
Can we still imagine that radiotherapy over 5 days could be offered one day for cancers other than breast cancer?
Dr. Sofia Rivera: Certainly. It all depends on the cancer cells. We know that those of prostate cancer are quite similar to those of the breast, it is a track. On the other hand, the cells of ENT cancers do not behave in the same way. A hypofractionated radiotherapy regimen does not seem relevant in this case.
Why do only women over 60 with this type of invasive breast cancer have access to it?
Dr. Sofia Rivera: Because in younger women, the risks of recurrence being higher, the radiation doses must be greater. However, the studies conducted so far have not made it possible to determine this necessary additional dosage. This type of breast cancer primarily concerns women over the age of 60 (40% of all breast cancers), they form the bulk of the trial cohort. We started with the figures we had. But of course, the goal is to address all age categories as quickly as possible.
What are the reactions of the patients?
Dr. Sofia Rivera: Once doubts about efficacy, toxicity or possible side effects have been dispelled, patients are enthusiastic, you can imagine. The psychological benefits are quite obvious since the therapeutic burden is reduced. With a shorter treatment, these are weeks gained without having to manage your illness. This is all the more positive for patients as radiotherapy comes to an end, after surgery and/or chemotherapy treatment. Finishing the treatment more quickly is experienced as a release.
You are the only center today to offer this protocol. Will others follow?
Dr. Sofia Rivera: Without a doubt. We are developing a national deployment project for the entire technique. Everyone has to gain from it, the patients of course, but also the centers which limit waiting times and will be able to take care of more patients.
The device in 4 essential points
- The system takes place over five days, all inclusive, from the initial radiotherapy consultation to the end-of-treatment consultation on the 5th day.
- For now, only patients over 60 with breast cancer without lymph node involvement are eligible for the program.
- The results are the same as with longer radiotherapy: no more risk of relapse and the same benefits as sessions spread over 3 or 5 weeks.
- At this stage, the earliest form of breast cancer (carcinoma in situ) is excluded from the scheme due to a lack of clinical trials.
Our expert: Dr Sofia Rivera, head of the breast radiotherapy department at Gustave-Roussy (Villejuif, 94).