Accelerated partial breast irradiation in the elderly: 5-year results of high-dose rate multi-catheter brachytherapy

OBJECTIVE: To evaluate clinical outcome after accelerated partial breast irradiation (APBI) in the elderly after high-dose-rate interstitial multi-catheter brachytherapy (HIBT). METHODS AND MATERIALS: Between 2005 and 2013, 70 patients underwent APBI using HIBT. Catheter implant was performed intra or post-operatively (referred patients) after lumpectomy and axillary sentinel lymph node dissection. Once the pathological results confirmed the indication of APBI, planification CT-scan was performed to deliver 34 Gy/10f/5d or 32 Gy/8f/4d. Dose-volume adaptation was manually achieved (graphical optimization). Dosimetric results and clinical outcome were retrospectively analyzed. Physician cosmetic evaluation was reported. RESULTS: With a median follow-up of 60.9 months [4.6 – 90.1], median age was 80.7 years [62 – 93.1]. Regarding APBI ASTRO criteria, 61.4%, 18.6% and 20% were classified as suitable, cautionary and non-suitable respectively. Axillary sentinel lymph node dissection was performed in 94.3%; 8 pts (11.5%) presented an axillary involvement. A median dose of 34 Gy [32 – 35] in 8 to 10 fractions was delivered. Median CTV was 75.2 cc [16.9 – 210], median D90 EQD2 was 43.3 Gy [35 – 72.6] and median DHI was 0.54 [0.19 – 0.74]. One patient experienced ipsilateral recurrence (5-year local free recurrence rate: 97.6%. Five-year specific and overall survival rates were 97.9% and 93.2% respectively. Thirty-four patients (48%) presented 47 late complications classified grade 1 (80.8%) and grade 2 (19.2%) with no grade ≥ 3. Cosmetic results were considered excellent/good for 67 pts (95.7%). CONCLUSION: APBI using HIBT and respecting strict rules of implantation and planification, represents a smart alternative between no post-operative irradiation and whole breast irradiation delivered over 6 consecutive weeks.