KEY TAKEAWAYS
- The study aimed to investigate the potential benefit of proton therapy in DIBH compared to FB for breast cancer patients, focusing on reducing heart and other organs at risk exposure.
- Researchers noticed limited median absolute reduction in heart dose with proton treatment in DIBH, indicating its relevance primarily for patients with substantial heart exposure reduction.
Proton therapy for breast cancer is commonly administered during free breathing (FB), yet the deep inspiration breath-hold (DIBH) technique offers potential advantages by displacing the heart inferiorly, away from the internal mammary nodes, thereby reducing heart dose.
Line Bjerregaard Stick and the team aimed to assess the potential benefits of proton therapy in DIBH compared to FB for selected patients to minimize heart and other organ exposure. The focus was on developing feasible proton plans for DIBH treatment delivery.
Researchers performed an inclusive analysis, including 16 patients diagnosed with left-sided breast cancer undergoing loco-regional proton therapy. FB and DIBH plans were devised for each patient utilizing spot-scanning proton therapy with 2-3 fields, robust and single field optimization. For DIBH plans, the minimum monitor unit per spot and spot spacing was increased to diminish treatment delivery time.
The results show that all plans adhered to target coverage constraints. The median mean heart dose experienced a statistically significant reduction from 1.1 to 0.6 Gy relative biological effectiveness (RBE) with the implementation of DIBH. No statistically significant difference was observed between the mean dose and V17Gy RBE in the ipsilateral lung, and the median treatment delivery time for DIBH plans decreased by 27% compared to FB plans, maintaining plan quality.
The study concluded that proton treatment in deep inspiration breath-hold may only be relevant for a subset of breast cancer patients with the largest reduction in heart exposure. No funding information was available.
Source: https://pubmed.ncbi.nlm.nih.gov/38404218/
Stick LB, Nielsen LL, Trinh CB, et al. (2024). “Spot-scanning proton therapy for early breast cancer in free breathing versus deep inspiration breath-hold.” Acta Oncol. 2024 Feb 26;63:56-61. doi: 10.2340/1651-226X.2024.28591. PMID: 38404218.
