Lateral wedge with medial only cardiac shielding (LEMONADE) technique in left chest wall adjuvant radiotherapy
Abstract
Background: This dosimetric study compared lateral wedge with medial only cardiac shielding (LEMONADE) technique, for left chest wall (LCW) irradiation against three other commonly used techniques.
Materials and methods: Dosimetric parameters of 22 consecutive LBC patients treated using the P1 (LEMONADE technique) were compared with 3 other virtually reconstructed plans: no cardiac shielding with paired wedges; P2 (paired wedges and medial only Y-direction shielding) and P3 (paired wedges and bilateral Y-direction shielding).
Results: P1 showed better target volume (TV) coverage with the mean 90% isodose coverage of 85.59% ± 5.44 compared to 78.90% ± 8.59 and 74.22% ± 9.50 for P2 and P3, respectively. Compared to no cardiac shielding, for a 4.65% drop in TV coverage the V26Gy of heart dropped from 6.68% to a negligible 0.85% for P1. TV receiving < 30Gy is also significantly lesser for P1 compared to P2 and P3 (5.42% vs 10.64% and 15.8%), whilst there is a small difference of 2.75% between no cardiac shielding and P1.
Conclusion: With the improvement in BC survival rate, cardiac toxicity associated with adjuvant irradiation for LBC is a major concern. P1 (LEMONADE) technique has a good compromise between cardiac sparing and target coverage and should suffice for most LCW irradiations. Furthermore, the LEMONADE technique is a simple, reproducible and involves fast planning for cardiac sparing, which is ideal for under-resourced departments with heavy workload.
Keywords: left chest wall radiotherapyleft breast carcinomacardiotoxicitymultileaf collimatorscardiac shielding
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