SIRARIS: Survey of internal mammary radiotherapy among radiation oncologists from Italy & Spain.

Background: Clinical guidelines for internal mammary chain (IMC) irradiation are not uniformly accepted, with notable differences between countries. This survey examines IMC irradiation practices among radiation oncologists in Italy and Spain.

Materials And Methods: An online survey was distributed to radiation oncologists via Google Forms. It included 26 questions, 9 on participants' epidemiological data and 17 on IMC irradiation. Participation was voluntary with no financial incentives.

Results: The survey, conducted in March and April 2024, received 94 responses (51 from Italy, 43 from Spain). Spanish oncologists are more likely to include IMC irradiation with any axillary involvement, regardless of tumor size or location. Italian oncologists more often take definitive stances of "always" or "never," while Spanish oncologists prefer the "sometimes" option. No significant differences were found in IMC definition, technique, doses, or respiratory control.

Conclusions: IMC radiotherapy indications remain controversial, with differences between Italian and Spanish oncologists.