Author: Md. Yousuf Ali, Parvin Akhter Banu, Ehteshamul Hoque, Qazi Mushtaq Hussain, Md Jobairul Islam, Md. Abdul Mannan, Sadia Afrin Sarah, Mostafa Aziz Sumon, Ahammad Al Mamun Sweet, AFM Kamal Uddin 👨🔬
Affiliation: Labaid Cancer Hospital & Superspeciality Centre 🌍
Purpose: Radiotherapy for left-sided breast cancer can induce cardiac injury. Deep Inspiration Breath Hold (DIBH) is a technique that minimizes cardiac exposure during treatment. This study compares dosimetric outcomes between DIBH using 3DCRT and Free-Breathing (FB) using VMAT and for left-sided breast cancer.
Methods: A retrospective study was conducted with 25 patients who underwent breast-conserving surgery or mastectomy. Each patient received CT simulation scans in both FB and DIBH positions using the Varian RGSC system. Treatment plans were generated using Eclipse TPS with the AAA algorithm. Patients were planned either with 3DCRT using DIBH and Free-Breath with VMAT and IMRT. All patients received 40 Gy in 15 fractions. DVH analysis evaluated clinical target volume (CTV) and organs at risk (OARs).
Results: Both techniques achieved adequate target coverage per RTOG-1005. PTV V95% was 96.58±0.95% for DIBH-3DCRT and 99.23±0.45% and 99.05±0.5% for FB-VMAT and IMRT respectively, with VMAT-FB providing more uniform coverage. The average heart dose was significantly lower with DIBH (2.67 Gy) compared to FB plans (3.90 Gy and 4.40 Gy, p = 0.000). Lung V20Gy was higher in 3DCRT-DIBH (18.03% vs. 12.51%, 14.05%) compared FB, but DIBH reduced V8Gy (34.8% to 25.42%) and V4Gy (71.61% to 38.6%). DIBH-3DCRT also delivered lower doses to the contralateral lung and breast compared to VMAT-FB.
Conclusion: DIBH-3DCRT is a viable alternative to FB-VMAT, IMRT for left-sided breast cancer in developing countries, offering effective target coverage with reduced cardiac and lung exposure. FB-VMAT is preferable for elderly patients or those unable to perform DIBH, with advantages in uniform coverage and shorter treatment times. IMRT, while effective, has disadvantages such as longer treatment times, higher monitor unit requirements, and increased low-dose exposure to the heart and lungs, making DIBH-3DCRT and VMAT the more optimal choice. Careful patient selection is crucial to optimize outcomes.