Abstract P1-15-12: Development of a photonumeric scale for acute radiation dermatitis in breast cancer patients

Abstract

Purpose Scales for rating acute radiation dermatitis (ARD) are inconsistent and have not been validated despite decades of clinical use, making ARD difficult to report reliably. We sought to design a photonumeric scale to consistently describe ARD in breast cancer patients undergoing radiation (RT). Methods Patients undergoing RT for breast cancer were enrolled on a prospective study that included photographs and reporting of physician-rated erythema, hyperpigmentation, and CTCAE toxicity score at baseline and 2, 4, and 6 weeks after initiating RT. Erythema and hyperpigmentation were also quantified using a hand-held colorimetric device. Photographs were taken using a standardized protocol that included 3 views to fully assess the breast/chest wall, axilla, and inframammary fold. 209 photographs from 35 patients with white skin (Fitzpatrick skin types I-IV) and 369 photographs from 50 patients with skin of color (Fitzpatrick skin types V-VI) were clustered according to the apparent severity of ARD. Due to the prevalence of hyperpigmentation that obscured erythema in patients with skin of color, separate images were used to illustrate ARD in this population. Two photonumeric scales (for white skin and skin of color) were developed via an iterative process until group consensus was achieved. Four raters with experience in the evaluation of ARD in breast cancer patients used the photonumeric scale to independently score the entire collection of photographs, sequenced in random order. Intra- and inter-rater agreements were assessed using weighted kappa scores. Results Of the 35 patients with white skin, 20% experienced severe erythema, and 40% experienced dry or moist desquamation. Of the 50 patients with skin of color, 34% experience severe hyperpigmentation, and 48% experienced dry or moist desquamation. Using the photonumeric scales, we observed high intra-rater agreement for independent ratings of erythema or hyperpigmentation (70 to 89% agreement fraction, kappa 0.55 to 0.81) and desquamation (79 to 87% agreement fraction, kappa 0.52 to 0.64). Similarly, we observed moderate to high inter-rater agreement for independent ratings of erythema or hyperpigmentation (61 to 76% agreement fraction, kappa 0.40 to 0.62) and desquamation (69 to 84% agreement fraction, kappa 0.36 to 0.58). Quantitative measurements of erythema in white patients using colorimetry correlated strongly with photonumeric grade (correlation coefficient 0.76, p<0.001), as did physician-rated erythema at the point-of-care (p<0.001). Fitzpatrick score was not significantly associated with maximum photonumeric erythema grade (p = 0.14). Conclusions We report a new photonumeric scale with high intra- and inter-rater reliability for acute radiation dermatitis in breast cancer patients. To our knowledge, this is the first rigorously evaluated scale that is applicable to patients across the spectrum of skin pigmentation, including white skin and skin of color. The photonumeric scale will facilitate consistent reporting of acute radiation dermatitis in research and clinical settings using a simple, standardized instrument. Future work will include prospective real-time clinical validation with multiple raters and correlation with patient-reported outcomes. Funded by a Munn Idea Grant (G011480). Citation Format: Dean Shumway, Eleanor M Walker, Nirav Kapadia, Thy Thy Do, Kent Griffith, Mary Feng, Bonnie DePalma, Reshma Jagsi, Yolanda Helfrich, Erin Gillespie, Alexandria Miller, Adam Liss, Lori J Pierce. Development of a photonumeric scale for acute radiation dermatitis in breast cancer patients [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-15-12.