SNP of Aromatase Predict Long-term Survival and Aromatase Inhibitor Toxicity in Patients with Early Breast Cancer: A Biomarker Analysis of the GIM4 and GIM5 Trials.

PURPOSE: In estrogen receptor-positive (ER+) breast cancer, single-nucleotide polymorphisms (SNP) in the aromatase gene might affect aromatase inhibitors (AI) metabolism and efficacy. Here, we assessed the impact of SNP on prognosis and toxicity of patients receiving adjuvant letrozole. EXPERIMENTAL DESIGN: We enrolled 886 postmenopausal patients in the study. They were treated with letrozole for 2 to 5 years after taking tamoxifen for 2 to 6 years, continuing until they completed 5 to 10 years of therapy. Germline DNA was genotyped for SNP rs4646, rs10046, rs749292, and rs727479. Log-rank test and Cox model were used for disease-free survival (DFS) and overall survival (OS). Cumulative incidence (CI) of breast cancer metastasis was assessed through competing risk analysis, with contralateral breast cancer, second malignancies and non-breast cancer death as competing events. CI of skeletal and cardiovascular events were assessed using DFS events as competing events. Subdistribution HR (sHR) with 95% confidence intervals were calculated through Fine-Gray method. RESULTS: No SNP was associated with DFS. Variants rs10046 [sHR 2.03, (1.04-2.94)], rs749292 [sHR 2.11, (1.12-3.94)], and rs727479 [sHR 2.62, (1.17-5.83)] were associated with breast cancer metastasis. Three groups were identified on the basis of the number of these variants (0, 1, >1). Variant-based groups were associated with breast cancer metastasis (10-year CI 2.5%, 7.6%, 10.7%, P = 0.035) and OS (10-year estimates 96.5%, 93.0%, 89.6%, P = 0.030). Co-occurrence of rs10046 and rs749292 was negatively associated with 10-year CI of skeletal events (3.2% vs. 10%, P = 0.033). A similar association emerged between rs727479 and cardiovascular events (0.3% vs. 2.1%, P = 0.026). CONCLUSIONS: SNP of aromatase gene predict risk of metastasis and AI-related toxicity in ER+ early breast cancer, opening an opportunity for better treatment individualization.

Randomized phase III trial of adjuvant epirubicin followed by cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) versus CMF followed by epirubicin in patients with node-negative or 1-3 node-positive rapidly proliferating breast cancer.

Adjuvant cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) have proven highly effective in rapidly proliferating breast cancer (RPBC). It has also been seen that sequential administration of doxorubicin and CMF is superior to their alternation, especially in indolent tumors. In a phase III study, we evaluated whether adjuvant epirubicin (E) followed by CMF is superior to the inverse sequence in RPBC. Patients with node-negative or 1-3 node-positive RPBC (Thymidine Labeling Index > 3% or histological grade 3 or S-phase > 10% or Ki67 > 20%) were randomized to receive E (100 mg/m(2) i.v. d1, q21 days for 4 cycles) followed by CMF (600, 40, 600 mg/m(2) i.v. d1 and 8, q28 days for 4 cycles) (E â†’ CMF) or CMF followed by E (CMF â†’ E) or CMF for 6 cycles. From November 1997 to December 2004, 1066 patients were enrolled: E â†’ CMF 440, CMF â†’ E 438, and CMF 188. At a median follow-up of 69 months, 5-year OS was 91% (95% CI 88-94) for E â†’ CMF and 93% (95% CI 90-95) for CMF â†’ E, with adjusted hazard ratio of 0.88 (95% CI 0.58-1.35), and DFS was 80% in both arms, with adjusted hazard ratio of 0.99 (95% CI 0.73-1.33, Cox model). Adverse events were similar, apart from a higher rate of neutropenia in the CMF â†’ E arm. No important differences in clinical outcome were observed between the two different sequences, making both a valid option in early breast cancer. Further molecular characterization of the tumors might help to identify subgroups achieving higher benefit from either sequence.