Partial breast irradiation as second conservative treatment for local breast cancer recurrence

Mastectomy is the treatment of reference for local relapse after breast cancer (BC). The aim of this study was to document the feasibility and the results of associating lumpectomy with partial breast irradiation by interstitial brachytherapy (IB) as local treatment for an isolated ipsilateral BC local recurrence (LR). Between 1975 and 1996 at Marseille and Nice Cancer Institutes, 4026 patients received lumpectomy and radiotherapy (RT) (50–80 Gy) for a localized breast cancer of which 473 presented a LR. Among these patients, 69 (14.6%) received a second lumpectomy followed by IB, which delivered 30 Gy (Nice, n = 24) or 45–50 Gy (Marseille, n = 45) with 3 to 8 192Ir wires in 1 or 2 planes on the 85% isodose. Median age at LR was 58.2 years, median follow-up since primary BC was 10 years, and median follow-up after the second conservative treatment was 50.2 months (range, 2–139 months). Immediate tolerance was good in all cases. Grade 2 to 3 long-term complications (LTC) according to IB dose were 0%, 28%, and 32%, respectively, for 30 Gy, 45 to 46 Gy, and 50 Gy ( p = 0.01). Grade 2 to 3 LTC according to total dose were 4% and 30%, respectively, for total doses (initial RT plus IB) ≤ 100 Gy or >100 Gy ( p = 0.008). Logistic regression showed that the only factor associated with Grade 2 to 3 complications was higher IB doses ( p = 0.01). We noted 11 second LRs (LR2), 10 distant metastases (DM), and 5 specific deaths. LR2 occurred either in the tumor bed (50.8%) or close to the tumor bed (34.3%) or in another quadrant (14.9%). Kaplan-Meier 5-year freedom from (FF) LR2 (FFLR2), FFDM, and DFS were 77.4%, 86.7%, and 68.9%, respectively. Overall 5-year survival (OS) was 91.8%. Univariate analysis showed the following factors associated with a higher FFLR2: (1) number of wires used for IB (3–4 vs. 5–8 wires, p = 0.006), (2) IB doses (30–45 Gy vs. 46–60 Gy, p = 0.05), (3) number of planes (1 vs. 2, p = 0.05), (4) interval between primary breast cancer and LR (< 36 months vs. ≥36 months, p = 0.06). Multivariate analysis showed two factors associated with better local control: (1) number of wires (5–8 wires, p = 0.013) and (2) interval between primary breast cancer and LR ≥36 months ( p = 0.039). The multivariate analysis showed two factors associated with better FFDM: (1) absence of initial axilla involvement ( p = 0.019) and (2) relapse in a different location ( p = 0.04). These two factors were also associated with a higher OS. Our experience showed that second con