Prospective Study of 3-Fraction Intra-Cavitary Accelerated Partial Breast Brachytherapy: Early Provider and Patient-Reported Outcomes of a Novel Regimen

Abstract

The optimal dose and fractionation for accelerated partial breast irradiation (APBI) is not known. We evaluated 3-fraction brachytherapy APBI in the context of a prospective clinical trial. Our purpose is to report early adverse effects and patient-reported outcomes (PROs) of this novel regimen. Eligible women were ≥ 50 years of age with ≤2 cm estrogen receptor positive, sentinel lymph node (SLN) negative invasive or in-situ breast cancer treated with breast conserving surgery. After frozen section pathology assessment of negative surgical margins and SLN(s), a multi-channel intra-cavitary brachytherapy catheter was placed intraoperatively. APBI was initiated on the second weekday after surgery after permanent section pathology confirmation. The prescription was 21 Gy in 3, once daily, fractions targeting the lumpectomy cavity with a 1 cm expansion. Common toxicity criteria for adverse effects (CTCAE v 4.0), 10-point linear analog scales, PROs version of the CTCAE (PRO-CTCAE), and Harvard Breast Cosmesis Scale (HBCS) were utilized for provider and patient-reported assessments. Seventy-three women, median age 66 years, were treated for invasive breast cancer (79%) or ductal carcinoma in situ (21%) between 2015 and 2017. Tumor grade was 1-2 in 88%. The median time to completion of all locoregional therapy (surgery and radiotherapy) was 6 days. After 14 months median follow-up, two patients (3%) had developed breast infections that resolved with oral antibiotics. There was no other treatment-associated adverse effects ≥ grade 2. The grade 1 seroma rate at 3 months was 20% (11/56 evaluable patients) which dropped to 8% (4/49) at 12 months; none required intervention. PROs are summarized in table 1. At 12 months, 91% reported overall QOL between 8 and 10 and patient-reported cosmesis was good or excellent in 95%. All patients were alive without relapse at the last follow-up. The 3-fraction, once daily, breast brachytherapy was associated with favorable early physician and PROs. These early results compare favorably with other reports including the more universally employed twice daily (3.4 Gy x 10) fractionation being studied in NSABP B-39. A randomized trial comparing these two approaches is warranted.Abstract TU_5_3369; Table 1Patient-Reported Outcomes associated with 3-fraction brachytherapy APBIPROsLASA 10Baseline (n=56)Post-RT (n=51)3 month (n=44)6 month (n=46)12 month (n=35)Quality of Lifeα8-1095%96%89%96%91%4-74%2%7%2%9%1-31%2%4%2%0%Breast CosmesisExcellent55%41%50%65%69%Good45%49%39%26%26%Fair0%10%9%9%6%Poor0%0%2%0%0%Painβ0-361%69%86%91%86%4-632%22%7%4%9%7-107%10%7%4%6%Fatigueβ0-361%55%75%63%71%4-625%37%16%24%12%7-1014%8%9%13%17%Skin BurnsNone100%90%88%96%100%Mild0%8%12%2%0%Moderate0%0%0%0%0%Severe0%0%0%0%0%Very Severe0%2%0%2%0%LASAα: Reported on a scale of 1-10 (1 indicating “worst” and 10 indicating “best”) LASAβ: Reported on a scale of 1-10 (1 indicating “none” and 10 indicating “as bad as it can be”). Open table in a new tab