Full axillary lymph node dissection and increased breast epidermal thickness 1 year after radiation therapy for breast cancer

Objective, Clinician- and Patient-Reported Evaluation of Late Toxicity Following Adjuvant Radiation for Early Breast Cancer: Long-Term Follow-Up Results of a Randomised Series

Background and Purpose: This study aimed to differentially assess the frequency and severity of late radiation-induced toxicity following adjuvant whole-breast irradiation for early breast cancer with conventional fractionation (CF) and moderate hypofractionation (mHF). Materials and Methods: Patients recruited in a previous randomised controlled trial comparing acute toxicity between CF and mHF without disease recurrence were included in a post hoc analysis. Spectrophotometric and ultrasonographic examinations were performed for an objective evaluation and subsequent comparison of long-term skin toxicity. Furthermore, patient- and clinician-reported outcomes were recorded. Results: Sixty-four patients with a median age of 58 (37-81) years were included. The median follow-up was 57 (37-73) months. A total of 55% underwent CF and 45% mHF. A total of 52% received a sequential boost to the tumour bed. A significant decrease in mean L* (p = 0.011) and an increase in a* (p = 0.040) and b* values (p < 0.001) were observed, indicating hyperpigmentation. In comparison with the non-irradiated breast, there was a significant increase in both cutis (+14%; p < 0.001) and subcutis (+17%; p = 0.011) thickness, significantly more pronounced in CF patients (p = 0.049). In CF patients only, a sequential boost significantly increased the local cutis thickness and oedema compared to non-boost regions in the same breast (p = 0.001 and p < 0.001, respectively). Conclusions: mHF objectively resulted in reduced long-term skin toxicity compared to CF. A sequential boost increased the local fibrosis rate in CF, but not in mHF. This might explain the subjectively reported better cosmetic outcomes in patients receiving mHF and reinforces the rationale for favouring mHF as the standard of care.

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

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.

Ultrasonographic Evaluation of Skin Toxicity Following Radiotherapy of Breast Cancer: A Systematic Review

The present review aimed to systematically review skin toxicity changes following breast cancer radiotherapy (RT) using ultrasound (US). PubMed and Scopus databases were searched according to PRISMA guidelines. The characteristics of the selected studies, measured parameters, US skin findings, and their association with clinical assessments were extracted. Seventeen studies were included with a median sample size of 29 (range 11-166). There were significant US skin changes in the irradiated skin compared to the nonirradiated skin or baseline measurements. The most observed change is skin thickening secondary to radiation-induced oedema, except one study found skin thinning after pure postmastectomy RT. However, eight studies reported skin thickening predated RT attributed to axillary surgery. Four studies used US radiofrequency (RF) signals and found a decrease in the hypodermis's Pearson correlation coefficient (PCC). Three studies reported decreased dermal echogenicity and poor visibility of the dermis-subcutaneous fat boundary (statistically analysed by one report). The present review revealed significant ultrasonographic skin toxicity changes in the irradiated skin most commonly skin thickening. However, further studies with large cohorts, appropriate US protocol, and baseline evaluation are needed. Measuring other US skin parameters and statistically evaluating the degree of the association with clinical assessments are also encouraged.