Effect of BioZorb® surgical marker placement on post-operative radiation boost target volume

OBJECTIVE: BioZorb® is a tumor bed marker placed during partial mastectomy for targeted post-operative radiation. This study was designed to evaluate BioZorb® effect on radiation boost clinical target volume (CTV), planning target volume (PTV), median dose to ipsilateral lung (Gy), and heart irradiation in left-sided cancers. METHODS: Data was collected via a retrospective cohort study with two study arms: BioZorb® intra-operative placement versus no BioZorb® placement. Patients were stratified by BMI, age, tumor laterality and volume, and cancer stage. Mean, standard deviation, median, range of cubic centimeters of clinical and planning target volume, cardiac dose in left-sided cancers, ipsilateral lung dose, and volume of ipsilateral lung receiving 20 Gy were reported. RESULTS: Of 143 patients, median CTV (cm(3)) was 8.7 and 14.2 (P = 0.0048), median PTV (cm(3)) was 53.2 and 79.6 (P = 0.0010), median ipsilateral lung Gy was 7.53 and 6.74 (P = 0.0099) and volume (cc) of ipsilateral radiation lung at 20 Gy was 13.4 and 12 (P = 0.008), and median heart Gy in left-sided cancers was 2.01 and 2.21 (P = 0.9952) in BioZorb® and non-BioZorb® arms, respectively. Patients with BMIs of 25–30 had CTV medians of 7.8 and 11.1 in BioZorb® and non-BioZorb® arms, respectively (P = 0.0293). CONCLUSION: The BioZorb® arm showed statistically significant reductions in CTV and PTV but not ipsilateral lung or heart irradiation.