2993 - Acute Toxicity in Patients with Skin of Color Treated with Hypofractionated Whole Breast Irradiation

Purpose/Objective(s): Prior studies suggest that patients with skin of color (SOC) may have lower rates of physician-reported radiation dermatitis, possibly due to the difficulty in assessing erythema on darker skin tones. However, data on acute toxicity effects of hypofractionated whole breast irradiation (HF-WBI) across racial groups remain limited. Furthermore, existing research has primarily focused on hyperpigmentation and dermatitis, with less attention given to pain, erythema, and edema—critical factors influencing patient experience and treatment tolerance. This study seeks to address these knowledge gaps by comparing acute toxicities in SOC versus White patients receiving HF-WBI and evaluating the influence of race.

Materials/Methods: We retrospectively reviewed the charts of 600 patients who received HF-WBI according to ASTRO 2018 guidelines at our institution from 2018 to 2023.Patients were categorized as White or SOC based on self-reported race/ethnicity. Acute toxicities were assessed using the Common Terminology Criteria for Adverse Events (CTCAE) v5.0 and recorded at on-treatment visits (OTV) and short-term follow-up (ST F/U) one-month post-treatment. Logistic regression was used to evaluate the association between race/ethnicity and acute toxicity prevalence. All statistical analyses were performed using Python v3.13.2.

Results: Of 600 patients, 334 (55.7%) were White, while 266 (44.3%) were SOC, including Hispanic (17.8%), Black/African American (16.1%), Asian (10.2%), and American Indian (0.2%). During OTV, White patients had significantly higher odds of grade 1 erythema than SOC patients (OR: 5.43; 95% CI: 2.59-11.37; P < 0.001). No patients had grade =2 erythema or edema. SOC patients were more likely to have grade 3 pain (OR: 3.55; 95% CI: 1.08-11.68; P = 0.037), though differences in combined grade 2 and 3 pain were not significant (OR: 1.19; 95% CI: 0.71-2.00; P = 0.50). At ST F/U, there were no significant racial differences in grade =2 pain (OR: 1.08; 95% CI: 0.10-11.55; P = 0.96) or grade =2 edema. However, White patients remained significantly more likely to experience grade 2 erythema (OR: 2.35; 95% CI: 1.49-3.72; P < 0.001).

Conclusion: This study highlights racial differences in acute toxicity following HF-WBI, with SOC patients experiencing higher rates of physician-reported grade 3 pain but lower rates of erythema compared to White patients. However, these toxicities largely resolved by short-term follow-up, with no significant differences in pain or edema persisting between racial groups. These findings suggest that when HF-WBI is delivered according to ASTRO 2018 guidelines, acute toxicity grade is relatively low in patients across race/ethnicity groups. Long-term follow-up analysis is warranted to confirm whether race-based disparities in these toxicities are present and whether they have lasting clinical impact.