CANTO: Skin Toxicities Evaluation of a Multicenter Large Prospective Cohort of Irradiated Patients for Early-Stage Breast Cancer.

PURPOSE/OBJECTIVE(S): Skin damage is a common toxicity during oncology management. Its assessment and understanding of the factors influencing its occurrence, is a major issue in the management of patients treated for an early breast cancer (BC).

MATERIALS/METHODS: CANTO (NCT01993498) is a prospective, multicentric, clinical cohort study of 11 400 patients with stage I-III BC, treated in 26 French cancer centers. In this study, we will evaluate the 8561 patients during their overall management for a BC. We are focus on specifical skin toxicities: Erythema, fibrosis, telangiectasia and skin color (CTCAE v4.0). These toxicities were assessed at 3-6 (M0), 12 (M12), 36 (M36), 60 (M60) months.

RESULTS: The prevalence of toxicities of interest varied over time, so at M0, 30.4% of patients had erythema while 17.7% of patients had fibrosis. At M12, M36 and M60, the prevalence of erythema decreased from 5.5 % to 2.5 % then to 2 %, respectively, while fibrosis remained stable at about 19 %. The prevalence of telangiectasia increased from 0.8 % to 7 % from M0 to M60. While the modification of skin color was 51.1 % at M0, and 10.6 % at M60. After adjustments, at M0, there was a statistically significant association between the onset of cutaneous erythema and obesity, the presence of axillary dissection, the type of surgery the age of the patient as well as the tumor phenotype RH+/HER2+ [OR: 0.79 [0.67; 0.93]]. Concerning fibrosis, a statistically significant association was found, at M12, with the age of the patient, obesity, tumor grade, Charlson score, type of surgery and mitotic index. Obesity and the age of the patient represent at M12 and M36 a risk significantly associated with the onset of telangiectasia. Concerning the modification of skin color at M12, we find a link between the age of the patient, obesity, tobacco consumption, tumor grade, Charlson score, type of surgery, and alcohol consumption [OR: 0.69 [0.51; 0.91]].

CONCLUSION: In this study we identified several risk factors for acute and late skin toxicity. The knowledge of its predictive factors allows a personalized management of the patient by adapting our treatments and our monitoring according to these different factors.