Multicatheter interstitial brachytherapy for breast cancer

Analysis of multicatheter interstitial brachytherapy: Accelerated partial breast irradiation in a retrospective cohort of early-stage breast cancer patients

PURPOSE

To determine cardiac dose received by patients treated with high dose rate interstitial brachytherapy. Patients with early-stage, node negative breast cancer can be treated using multi-catheter interstitial brachytherapy accelerated partial breast irradiation (MIB-APBI), with the benefit of reduced treatment volumes and favorable toxicity.

METHODS AND MATERIALS

We conducted a retrospective review of left-sided breast cancer patients treated using MIB-APBI at our institution since 2014. The mean heart dose (MHD) was calculated using the Oncentra 3.2 planning system. The minimum distance between the planning target volume (PTVeval) and heart contour was measured manually.

FINDINGS

81 patients were included. The upper outer quadrant was the most common site. The MHD was 97.8 cGy (EQD2a/b=2) (range 22-229 cGy). MHD significantly correlated with the closest distance between PTVeval and heart contour (correlation coefficient -0.823, p <0.001); size of PTVeval (cc) and quadrant location did not.

CONCLUSIONS

Appropriately selected women with early-stage, low-risk, left-sided breast cancer who received MIB-APBI had acceptable MHD. There was a strong correlation between the distance of PTVeval and MHD. Quadrant breast tumor is in cannot be used as a surrogate for MHD in brachytherapy. Our findings contribute to the growing evidence of the utility and safety of MIB-APBI.

Performance evaluation of buildup bolus during external radiotherapy of mastectomy patients: treatment planning and film dosimetry

A buildup bolus is used during the post-mastectomy radiotherapy (PMRT) to overcome under-dosage issues in the chest wall. The current study is aimed at evaluating the performance of a bolus in dose enhancement through both film dosimetry and treatment planning approaches. Twenty patients were enrolled in current research. The received dose by the skin at the lateral and medial regions of the chest wall in the presence and absence bolus was evaluated. Film dosimetry results showed that the presence of the bolus can averagely increase the skin dose by about 80% (P value < 0.001) and 92% (P value < 0.001) in lateral and medial regions, respectively. No significant difference was observed between the measured and treatment planning system (TPS)-calculated dose values in the presence of bolus. The presence of the bolus can considerably increase the absorbed dose by superficial chest wall regions. The TPS shows a favorable performance in superficial dose calculations in the presence of the buildup bolus. Hosseini et al.: demonstration of implemented research in the current study.