Arguments	Emblematic Quotes
Advantages of IORT
Non-inferiority compared to WBRT if strict adherence to patient selection criteria	“To compare efficacy, we rely on published studies which show a very marginal benefit in favor of standard treatment. The selection of patients in these studies was perhaps a little less strict than what we do...We take a lot of precautions to have an equivalent benefit between the two treatments. With very precise criteria, the two treatments are equivalent.” (P15)
Precision of the irradiated area	“In WBRT there is radiotherapy of the whole breast and then there is over-irradiation localized on the area of the excision. With IORT, we are sure that the boost, is done exactly where it should be done.” (P16)
One-day treatment	“Avoiding round trips and transportation is a big advantage for patients who are more vulnerable. The benefit in terms of quality of life is clear.” (P1)
Well-tolerated treatment and low toxicity	“Toxicity is less at the skin level and at the level of peripheral organs.” (P13) “The breast remains supple, it is not fibrotic, we don’t have the problems of burning that we have with external radiotherapy.” (P7) “There is less deformation of the breast, especially in elderly women, who often have significant late deformation of the breast treated with conventional radiotherapy.” (P8)
Positive psychological impact for the patient	“For the patient, it’s psychologically more positive to have a one-day treatment, meaning that you arrive in the morning and go home after the surgery. There is just a continuous oral treatment to take, and the psychological impact is much less than with WBRT, and the patients have an excellent experience.” (P13)
Important benefit for older women with small tumors	“We have been slow to explore therapeutic de-escalation and giving an 80-year-old woman with a 6-mm tumor, six weeks of radiation is heresy. This is really the concept of therapeutic de-escalation. For small cancers, these are patients for whom the Americans and the British say in their standards that we can do without radiation, with relatively high relapse rates. Rather than not doing radiation, let’s do targeted radiotherapy.” (P8)
Disadvantages of IORT
Unknown long-term risk of recurrence and difficulty in selecting patients	“In highly selected patients, we do not feel that there is a greater risk of local relapse. Afterwards, we need a 10-year follow-up.” (P1) “This is a technique that is still being evaluated and we do not have that much experience with it.” (P12)
Need of extra time to share decision with the patient	“Initially I was trying to present things in a very neutral way by really explaining even the uncertainties of medicine, because we have plenty of them, and in fact patients don’t expect that at all. They want to be guided… even if we make them understand that it is a choice, this choice must be guided.” (P14)
Delay to initiate treatment	“Conventional treatment which consists of an outpatient lumpectomy and sentinel node sampling, can usually be completed within 15 days. If IORT is chosen, an angio-mammogram, an MRI and a consultation with the radiation therapist are required, which takes more time. The date of the breast surgery is necessarily delayed compared to the one that could be proposed. This is not serious from an oncological point of view for tumors with a good prognosis, but it is sometimes a little complicated to manage with patients.” (P13)
Additional radiotherapy often needed	“It takes about ten days to get the results and to know whether or not additional radiotherapy is needed... I always approach the consultation with the patients by saying: we propose the treatment but, in any case, what counts is the definitive analysis and as long as we don’t have that, we can’t affirm that you won’t need another postoperative treatment.” (P15)
Negative psychological impact for the patient	“That’s the psychological problem of the IORT. We tell the women it’s nothing at all, the little lady sees the surgeon, we operate on her, we don’t really talk about radiation, we wake her up, and then finally we announce that we have to do radiation... it’s certain that in this case, she’ll say to herself that it’s perhaps much more serious, and there’s anguish.” (P8) “If the IORT is not validated and additional radiation therapy is required, women are extremely disappointed. The disappointment and the psychological impact are greater than for a patient scheduled for conventional radiotherapy and who must have more sessions.” (P7)
Compliance with adjuvant endocrine therapy needed	“They absolutely have to comply with the anti-hormonal treatment, and we don’t have the key to know if they will take it knowing there are problems of compliance to hormone therapy for breast cancer. We need to make women accountable for this.” (P14)
Specific side effects	“The inflammatory reactions are stronger with intraoperative radiotherapy. As an immediate reaction, there may be greater discomfort, redness, pain and inflammatory effects. When patients are a little obese, they have more skin reactions and pain” (P9)
Increased logistical constraints for hospital and physicians	“Even when the organization is satisfactory, IORT extends the operating time. This can be a constraint for the anesthesia team, for the surgeons. Normally it lasts about three quarters of an hour to an hour longer, so it is a time to be considered for the occupation of the room and the occupation of the staff.” (P15)
No benefit compared to other techniques	“With hypo-fractionated radiotherapy there is less fatigue, less travel, no increased delay in care. It is widely used in some centers for elderly women. Duration 3 weeks and one day.” (P3) “For patients over 60 years, with good prognosis tumors, we propose local brachytherapy, i.e., a shorter treatment, which is less irradiating, which targets the operating bed.” (P4)
	WBRT, whole breast radiotherapy; IORT, intraoperative radiotherapy.