Comparative dosimetric findings using accelerated partial breast irradiation across five catheter subtypes (Radiation Oncology)

PurposeAccelerated partial breast irradiation (APBI) with balloon and strut adjusted volume implants (SAVI) show promising results with excellent tumor control and minimal toxicity. Knowing the factors that contribute to a high skin dose, rib dose, and D 95 coverage may reduce toxicity, improve tumor control, and help properly predict patient outcomes following APBI.Methods and materialsA retrospective analysis of 594 patients treated with brachytherapy based APBI at a single institution from May 2008 to September 2014 was grouped by applicator subtype. Patients were treated to a total of 34 Gy (3.4 Gy x 10 fractions over 5 days delivered BID) targeting a planning target volume (PTV) 1.0 cm beyond the lumpectomy cavity using a high dose rate source. Results: SAVI devices had the lowest statistically significant values of D max Skin (81.00 ± 29.83), highest values of D 90 (101.50 ± 3.66), and D 95 (96.09 ± 4.55). SAVI-mini devices had the lowest statistically significant values of D max Rib (77.66 ± 32.92) and smallest V 150 (18.01 ± 3.39). Multi-lumen balloons were able to obtain the smallest V 200 (5.89 ± 2.21). Strut-based applicators were more likely to achieve a D max Skin and a D max Rib less than or equal to 100 %. The effect of PTV on V 150 showed a strong positive relationship (p