The role of breath holding technique on minimizing cardiac dose in left breast cancer irradiation in the adjuvant setting

Abstract

Author(s): Ruaa Ali Seror* and Manwar Al-Naqqash

Breast Cancer (BC) is one of the top cancers in Iraq. It is the leading cancer among females for morbidity and mortality. One of the most concerning adverse events of breast RT is cardio-toxicity. Cardiac doses can be reducing by physical separation the heart from the volume of treatment, as in Deep Inspiration Breath Hold (DIBH). Study aimed to quantify the risk of cardiotoxicity from radiation in left BC and to describe the roles of DIBH by ABC devise on minimizing cardiac dose from radiation in left BC. A retrospective dosimetry study of 50 left BC women were enrolled whom were consecutively treated as 26 female with left BC at Baghdad Radiation Oncology Center, Baghdad Medical City and 24 females with left BC at Al-Safeer Oncology Center. The study conducted in period between December 2022 and May 2023, where planning for treatment with adjuvant RT. Data collected included age, T-N stages, grades, tumour primary site, histopathology, Lymph-Vascular Invasive (LVI), Perineural Invasion (PNI), previous treatments, dose of radiation, protocols of management, hormonal receptors status, HER2 status, and surgery (mastectomy or BCS). We used the ABC device (Elekta, Sweden) technique that found in Al-Safeer Oncology Center as we get agreement for and approval to conduct this study. The mean age was (53.92 ± 10.59) years for Free Breathing group (FB) (n=26) and (48.29 ± 11.82) years for ABC group (n=24). All women received 40.05 G dose of radiotherapy. Mastectomy done in 16(32%) of cases in FB group and in 15(30%) of cases in ABC group. The mean PTVT ref. vol% of ABC group (97.577 ± 1.069 cm3) was better in covering than that of FB group (92.135 ± 2.651 cm3), (p<0.0001). Additionally, the mean PTVN ref. vol% of ABC group (97.79 ± 1.417 cm3) was higher than that of FB group (95.296 ± 2.954 cm3), (p<0.0001). The mean heart vol. of ABC group (567.969 ± 102.202 cm3) was lower than that of FB group (682.287 ± 167.442 cm3), (p=0.009). The mean D_max of heart in ABC group (3113.279 ± 906.777 Gy) was lower than in FB group (3787.865 ± 797.608 Gy), (p=0.028) in conclusion to the knowledge, this first time study conducted in Iraq compare between DIBH (ABC devise) and FB in adjuvant setting of left BC radiotherapy. Both PTV of target and lymph nodes better coverage in DIBH (ABC device) than FB. The cardiac mean dose, mean D_max and mean volume are lower in DIBH (ABC device) than FB

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