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Impact of adjuvant trastuzumab on locoregional failure rates in a randomized clinical trial: North Central Cancer Treatment Group N9831 (alliance) study
Author(s) -
Vargas Carlos E.,
Thorpe Cameron S.,
Dueck Amylou C.,
Tenner Kathleen S.,
Davidson Nancy E.,
Martino Silvana,
Pisansky Thomas M.,
Hwang E. Shelley,
Halyard Michele Y.,
Pockaj Barbara A.,
Perez Edith A.
Publication year - 2020
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.33154
Subject(s) - medicine , trastuzumab , adjuvant , randomized controlled trial , oncology , clinical trial , alliance , cancer , adjuvant therapy , surgery , breast cancer , political science , law
Background The goal of this study was to assess the impact of trastuzumab on locoregional failure. METHODS The analysis included 2763 patients with HER2‐positive (HER2+) breast cancer who were randomly assigned to adjuvant doxorubicin (A), cyclophosphamide (C), paclitaxel (T) and trastuzumab (H) (arm A, AC→T [n = 922]; arm B, AC→T→H [n = 988]; arm C, AC→T+H→H [n = 853]). Radiotherapy was given after AC→T concurrently with H. Radiotherapy was given after lumpectomy (L) or after mastectomy (M) with ≥4 positive lymph nodes but was optional for 1 to 3 positive lymph nodes. Locoregional failures at 10 years (LFR10) as first events were compared using competing risk analysis. Results The median follow‐up was 13.0 years. The first site of failure was local‐only in 96 cases, locoregional in 16 cases, regional in 32 cases, and not specified in 2 cases; LFR10 was 4.8% (95% CI 4.1%‐5.7%). LFR10 was 5.5% (95% CI 4.3%‐7.2%), 4.9% (95% CI 3.7%‐6.4%), and 2.8% (95% CI 1.9%‐4.1%) in arms A, B, and C (B vs A: hazard ratio [HR] 0.91, P = .62; C vs A: HR 0.72, P = .12). For estrogen receptor–positive patients, LFR10 was 3.7% (95% CI 2.8%‐4.8%) and for estrogen receptor–negative patients, it was 6.1% (95% CI 5.0%‐7.4%; HR 0.61, P = .004). Local treatment included L+RT (n = 1044 [38%]), M+RT (n = 1025 [37%]), and M (n = 694 [25%]). LFR10 was 6.% (95% CI 5.0%‐7.8%), 3.0% (95% CI 2.1%‐4.3%), and 5.5% (95% CI 4.0%‐7.4%) for L+RT, M+RT, and M, respectively (M+RT vs L+RT: HR 0.43, P < .001; M vs L+RT: HR 0.88, P = .57). For 1 to 3 positive lymph nodes, LFR10 was 6.5% (95% CI 4.8%‐8.9%), 4.1% (95% CI 2.4%‐7.0%), and 4.3% (95% CI 2.9%‐6.5%) in L+RT, M+RT, and M, respectively (M vs L+RT: HR 0.68, P = .14; M vs M+RT: HR 1.2, P = .6). Conclusion Low 10‐year LFRs were seen regardless of trastuzumab use. Differences in local therapy in patients with 1 to 3 positive lymph nodes did not appear to improve local control. Local therapy studies for HER2+ and other tumor characteristics are important as the role of local therapies continues to evolve.