Outcomes For Apbi With Strut-Based Brachytherapy: 596 Patients With 39-Month Median Follow-Up

Purpose/Objective(s)The SAVI Collaborative Research Group (SCRG) created a retrospective database to study the long-term outcomes of women receiving accelerated partial breast irradiation (APBI) using strut-based applicators.Materials/MethodsPatients for this analysis were required to have reported dosimetry data and follow-up of at least 12 months post-APBI. Patients were treated with APBI using the strut-based brachytherapy device with conventional dose and fractionation (3.4 Gy x 10 fx, BID). Treatment planning goals for the planning target volume were a V90 > 90%, V150 < 50 cc, and V200 < 20 cc. Patients were followed regularly by their radiation oncologist and outcome was graded based on the CTCAE v3.0 (common terminology criteria for adverse events, version 3.0). Recurrence (raw and actuarial) rates were also calculated based on the follow-up. Cosmesis was graded using the Harvard Scale.Results596 total patients were included in this analysis (69% invasive histology). The median age was 63.0 yrs (range 40-88 yrs), with 88% post-menopausal. Median tumor size was 11.0 mm (range 0.0-60 mm) with 89% being estrogen receptor positive. All patients completed APBI as planned with no serious adverse events. All patients met the dosimetric criteria. Late toxicity (grade ≥ 2) rates were low; telangiectasias (1.0%), seroma (3.0%) and fat necrosis (0.8%). Good/excellent cosmesis was seen in > 94% of subjects at all times of follow-up (6 months to 60 months). Local control was excellent with a true recurrence/marginal miss rates of 1.3% (n = 8), 0.96% (n = 4) and 2.3% (n = 4) for all subjects, invasive and DCIS subgroups, respectively. The ipsilateral/elsewhere recurrence rate was 1.5% (n = 9), 1.5% (n = 6) and 1.7% (n = 3) for all subjects, invasive and DCIS subgroups, respectively. The 3-yr actuarial rates for TR/MM were 1.1%, 0.85%, and 2.4% for all subjects, invasive and DCIS subgroups, respectively.ConclusionsFor this large (n = 596) population of patients, with 39 months of median follow-up, strut-based brachytherapy appears to be a well-tolerated and effective treatment. Local control in this large population is similar to that seen with other brachytherapy techniques for APBI at this duration of follow-up. Purpose/Objective(s)The SAVI Collaborative Research Group (SCRG) created a retrospective database to study the long-term outcomes of women receiving accelerated partial breast irradiation (APBI) using strut-based applicators. The SAVI Collaborative Research Group (SCRG) created a retrospective database to study the long-term outcomes of women receiving accelerated partial breast irradiation (APBI) using strut-based applicators. Materials/MethodsPatients for this analysis were required to have reported dosimetry data and follow-up of at least 12 months post-APBI. Patients were treated with APBI using the strut-based brachytherapy device with conventional dose and fractionation (3.4 Gy x 10 fx, BID). Treatment planning goals for the planning target volume were a V90 > 90%, V150 < 50 cc, and V200 < 20 cc. Patients were followed regularly by their radiation oncologist and outcome was graded based on the CTCAE v3.0 (common terminology criteria for adverse events, version 3.0). Recurrence (raw and actuarial) rates were also calculated based on the follow-up. Cosmesis was graded using the Harvard Scale. Patients for this analysis were required to have reported dosimetry data and follow-up of at least 12 months post-APBI. Patients were treated with APBI using the strut-based brachytherapy device with conventional dose and fractionation (3.4 Gy x 10 fx, BID). Treatment planning goals for the planning target volume were a V90 > 90%, V150 < 50 cc, and V200 < 20 cc. Patients were followed regularly by their radiation oncologist and outcome was graded based on the CTCAE v3.0 (common terminology criteria for adverse events, version 3.0). Recurrence (raw and actuarial) rates were also calculated based on the follow-up. Cosmesis was graded using the Harvard Scale. Results596 total patients were included in this analysis (69% invasive histology). The median age was 63.0 yrs (range 40-88 yrs), with 88% post-menopausal. Median tumor size was 11.0 mm (range 0.0-60 mm) with 89% being estrogen receptor positive. All patients completed APBI as planned with no serious adverse events. All patients met the dosimetric criteria. Late toxicity (grade ≥ 2) rates were low; telangiectasias (1.0%), seroma (3.0%) and fat necrosis (0.8%). Good/excellent cosmesis was seen in > 94% of subjects at all times of follow-up (6 months to 60 months). Local control was excellent with a true recurrence/marginal miss rates of 1.3% (n = 8), 0.96% (n = 4) and 2.3% (n = 4) for all subjects, invasive and DCIS subgroups, respectively. The ipsilateral/elsewhere recurrence rate was 1.5% (n = 9), 1.5% (n = 6) and 1.7% (n = 3) for all subjects, invasive and DCIS subgroups, respectively. The 3-yr actuarial rates for TR/MM were 1.1%, 0.85%, and 2.4% for all subjects, invasive and DCIS subgroups, respectively. 596 total patients were included in this analysis (69% invasive histology). The median age was 63.0 yrs (range 40-88 yrs), with 88% post-menopausal. Median tumor size was 11.0 mm (range 0.0-60 mm) with 89% being estrogen receptor positive. All patients completed APBI as planned with no serious adverse events. All patients met the dosimetric criteria. Late toxicity (grade ≥ 2) rates were low; telangiectasias (1.0%), seroma (3.0%) and fat necrosis (0.8%). Good/excellent cosmesis was seen in > 94% of subjects at all times of follow-up (6 months to 60 months). Local control was excellent with a true recurrence/marginal miss rates of 1.3% (n = 8), 0.96% (n = 4) and 2.3% (n = 4) for all subjects, invasive and DCIS subgroups, respectively. The ipsilateral/elsewhere recurrence rate was 1.5% (n = 9), 1.5% (n = 6) and 1.7% (n = 3) for all subjects, invasive and DCIS subgroups, respectively. The 3-yr actuarial rates for TR/MM were 1.1%, 0.85%, and 2.4% for all subjects, invasive and DCIS subgroups, respectively. ConclusionsFor this large (n = 596) population of patients, with 39 months of median follow-up, strut-based brachytherapy appears to be a well-tolerated and effective treatment. Local control in this large population is similar to that seen with other brachytherapy techniques for APBI at this duration of follow-up. For this large (n = 596) population of patients, with 39 months of median follow-up, strut-based brachytherapy appears to be a well-tolerated and effective treatment. Local control in this large population is similar to that seen with other brachytherapy techniques for APBI at this duration of follow-up.