Dosimetric parameters of the axillary-lateral thoracic junction in predicting risk of breast cancer-related lymphedema
In brief
Dose covering >50% of axillary-lateral thoracic junction triples lymphedema risk
In a cohort of 722 breast-cancer patients treated with surgery and radiotherapy, an ALTJ V35Gy greater than 50% was linked to a three-fold higher chance of developing stage 2 or worse lymphedema, independent of axillary node dissection. Adding this dose metric modestly improved predictive models, but prospective validation is needed.
- Journal
- Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology (Q1)
- Published
- 13 August 2026
- Study design
- Unclassified
- Evidence level
- Level 5, Expert Opinion (CEBM 5)
- Authors
- Soon Woo Hong, Eun-Kyu Kim, Hee-Chul Shin, Jaewon Beom, Jae-Young Lim, In Ah Kim, et al.
- PMID
- 42595256
- DOI
- 10.1016/j.radonc.2026.111725
Why clinicians should know about it
- Picked for Medical Physics (top studies of the week, 16 August 2026): ALTJ dose‑volume predicts breast cancer‑related lymphedema
Abstract
INTRODUCTION: Regional nodal irradiation (RNI) is associated with breast cancer-related lymphedema (BCRL), yet varying definition of extensive RNI among radiation oncologists leads to the inconsistencies in risk assessment. Recently, the axillary-lateral thoracic junction (ALTJ) has been proposed as a potential organ-of-interest, but its role remains controversial. This study investigates the predictive role of ALTJ dose-volumetric parameters in BCRL development. METHODS AND MATERIALS: We identified patients with breast cancer who underwent surgery and adjuvant radiotherapy (2018 - 2020). BCRL was defined as newly developed upper arm lymphedema after radiotherapy, with International Society of Lymphology stage ≥ 2. Following retrospective ALTJ contouring, multivariable Cox regression and Random Survival Forest models were developed using clinical factors and ALTJ dosimetric parameters. Model performance was evaluated via Harrell's C-index and 24-month landmark analysis. RESULTS: We investigated 722 patients with a median follow-up of 30 months. 283 (39.2%) underwent axillary lymph node dissection (ALND). In multivariate Cox regression, along with ALND, ALTJ V35Gy > 50% was associated with an increased risk BCRL (p = 0.003, HR 3.07), whereas binary RNI status wasn't (p = 0.363). When comparing multivariable prognostic frameworks, Model B (incorporating ALTJ V35Gy) demonstrated a more favorable statistical fit than Model A (incorporating RNI). While Model B yielded a numerically higher C-index (0.753 vs. 0.749), this gain was not statistically significant. CONCLUSIONS: This study highlights the significance of the ALTJ as an organ-of-interest in breast cancer patients who underwent radiotherapy. Incorporating ALTJ dosimetric parameters into predictive models enhances prognostic accuracy, addressing the limitations of variable RNI field definitions.
Abstract as published, via PubMed.
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