Locoregional recurrence and survival outcomes by type of local therapy and trastuzumab use among women with node-negative, HER2-positive breast cancer.
BACKGROUND
While human epidermal growth factor receptor 2 (HER2) overexpression is an adverse breast cancer prognostic factor, it is unclear whether there are differences in outcomes between types of local treatment in this population. This retrospective study examined locoregional recurrence and survival in women with node-negative, HER2+ breast cancer treated with breast-conserving therapy (BCT) versus mastectomy.


METHODS
Subjects were 748 patients with pT1-2, N0, M0 HER2+ breast cancer, treated with BCT (n = 422) or mastectomy (n = 326). Trastuzumab was used in 54 % of subjects. The 5-year Kaplan-Meier locoregional recurrence free survival (LRRFS), breast cancer specific survival (BCSS), and overall survival (OS) were compared between cohorts treated with BCT versus mastectomy. Subgroup analyses of LRR and survival were performed separately among patients treated with BCT or mastectomy to examine the effect of trastuzumab on outcomes in each group.


RESULTS
Median follow-up was 4.4 years. Patients treated with mastectomy had higher proportions of grade 3 histology (69 vs 60 %, p = 0.004) and lower rates of hormone therapy (51 vs 64 %, p < 0.001) and trastuzumab therapy (50 vs 57 %, p = 0.04). The 5-year outcomes in women treated with BCT compared with mastectomy were: LRRFS 98.0 versus 98.3 % (p = 0.88), BCSS 97.2 versus 96.1 % (p = 0.70), and OS 95.5 versus 93.4 % (p = 0.19). Trastuzumab was associated with similar LRRFS and improved OS in both local treatment groups.


CONCLUSIONS
BCT is safe in the population of women with pT1-2, N0, HER2+ breast cancer, providing high rates of locoregional control and survival equivalent to mastectomy. Trastuzumab was associated with improved survival in both groups.
Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver Island Centre, Victoria, BC, Canada.
David J
DJ
Peterson
Pauline T
PT
Truong
Betro T
BT
Sadek
Cheryl S
CS
Alexander
Bradley
B
Wiksyk
Mina
M
Shenouda
Rita Abi
RA
Raad
Alphonse G
AG
Taghian
D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000378:metabolism / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008198:Lymph Nodes / Q000473:pathology*; D008408:Mastectomy; D015412:Mastectomy, Segmental; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000378:metabolism / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012189:Retrospective Studies; D015996:Survival Rate; D000068878:Trastuzumab
D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D000068878:Trastuzumab; C508053:ERBB2 protein, human