Ultrasound‐Based Grading System for Radiation‐Induced Acute Breast Toxicity

Abstract

Objectives To introduce an ultrasound‐based scoring system for radiation‐induced breast toxicity and test its reliability. Methods Breast ultrasound (BUS) was performed on 32 patients receiving breast radiotherapy (RT) to assess the radiation‐induced acute toxicity. For each patient, both the untreated and irradiated breasts were scanned at five locations: 12:00, 3:00, 6:00, 9:00, and tumor bed to evaluate for heterogenous responses to radiation within the entire breast. In total, 314 images were analyzed. Based on ultrasound findings such as skin thickening, dermis boundary irregularity, and subcutaneous edema, a 4‐level, Likert‐like grading scheme is proposed: none (G0), mild (G1), moderate (G2), and severe (G3) toxicity. Two ultrasound experts graded the severity of breast toxicity independently and reported the inter‐ and intra‐observer reliability of the grading system. Imaging findings were compared with standard clinical toxicity assessments using Common Terminology Criteria for Adverse Events (CTCAE). Results The inter‐observer Pearson correlation coefficient (PCC) was 0.87 (95% CI: 0.83–0.90, P < .001). For intra‐observer repeatability, the PCC of the repeated scores was 0.83 (95% CI: 0.78–0.87, P < .001). Imaging findings were compared with standard clinical toxicity assessments using CTCAE scales. The PCC between BUS scores and CTCAE results was 0.62 (95% CI: 0.35–0.80, P < .001). Among all locations, 6:00 and tumor bed showed significantly greater toxicity compared with 12:00 (P = .04). Conclusions BUS can investigate the cutaneous and subcutaneous tissue changes after RT. This BUS‐based grading system can complement subjective clinical assessments of radiation‐induced breast toxicity with cutaneous and subcutaneous sonographic information.

Quantitative ultrasound radiomics for monitoring radiation-induced toxicity following breast radiotherapy

“…From previous literatures, the skin thickness of breast is around 1.5 to 3.5 mm [10] and the skin thickening was found to be correlated with the progression of radiation toxicity [8,[11][12][13][14][15][16]. In addition to the superficial skin, studies have highlighted that subcutaneous tissues can exhibit noticeable changes in acute breast toxicity, such as subcutaneous edema, for severe cases [17]. To capture both the superficial skin and subcutaneous tissues, we crop a region of interest (ROI) of 8 mm thickness with the skin surface as the upper bound.…”