Barlow, William E.

Purpose To determine the optimal dose and schedule of anthracycline and taxane administration as adjuvant therapy for early-stage breast cancer. Patients and Methods A 2 × 2 factorial design was used to test two hypotheses: (1) that a novel continuous schedule of doxorubicin-cyclophosphamide was superior to six cycles of doxorubicin-cyclophosphamide once every 2 weeks and (2) that paclitaxel once per week was superior to six cycles of paclitaxel once every 2 weeks in patients with node-positive or high-risk node-negative early-stage breast cancer. With 3,250 patients, a disease-free survival (DFS) hazard ratio of 0.82 for each randomization could be detected with 90% power with two-sided α = .05. Overall survival (OS) was a secondary outcome. Results Interim analyses crossed the futility boundaries for demonstrating superiority of both once-per-week regimens and once-every-2-weeks regimens. After a median follow-up of 6 years, a significant interaction developed between the two randomization factors (DFS P = .024; OS P = .010) in the 2,716 patients randomly assigned in the original design, which precluded interpretation of the two factors separately. Comparing all four arms showed a significant difference in OS (P = .040) but not in DFS (P = .11), with all treatments given once every 2 weeks associated with the highest OS. This difference in OS seemed confined to patients with hormone receptor–negative/human epidermal growth factor receptor 2 (HER2) –negative tumors (P = .067), with no differences seen with hormone receptor–positive/HER2-negative (P = .90) or HER2-positive tumors (P = .40). Conclusion Patients achieved a similar DFS with any of these regimens. Subset analysis suggests the hypothesis that once-every-2-weeks dosing may be best for patients with hormone receptor–negative/HER2-negative tumors.

Purpose Patients with inflammatory breast cancer (IBC) or locally advanced breast cancer (LABC) were randomly assigned to 21-day doxorubicin and cyclophosphamide administered for five cycles (standard arm) versus weekly doxorubicin and daily oral cyclophosphamide administered with granulocyte colony-stimulating factor support for 15 weeks (continuous arm). All patients had subsequent weekly paclitaxel for 12 weeks before surgery. Patients and Methods Patients (n = 372) were randomly assigned to the standard arm (n = 186) or the continuous arm (n = 186) stratified by disease type (LABC, n = 256; IBC, n = 116). The primary outcome was microscopic pathologic complete response (pCR) at surgery. Secondary outcomes included disease-free survival, overall survival, and toxicity. Results More patients in the standard arm had grade 3 to 4 leukopenia and neutropenia, but there were more instances of stomatitis/pharyngitis and hand-foot skin reaction in the continuous arm. Assessed among 356 eligible patients, pCR was not different between the treatment groups stratified by disease type (P = .42). In subset analysis, higher pCR rates were observed in the continuous arm versus the standard arm only for stage IIIB disease (P = .0057) and in IBC (P = .06). Comparison of overall survival and disease-free survival showed no difference between treatment groups (P = .37 and P = .87, respectively). Conclusion No significant clinical benefit was seen for the investigational arm in this trial overall.

Abstract Background: Taxane-induced peripheral neuropathy is a dose-limiting side effect that leads to suboptimal cancer treatment and diminished quality of life. The mode of taxane neurotoxicity is unclear, but may be through stabilization of microtubules and induction of spindle checkpoint, leading to cell cycle arrest at G2/M. Fanconi Anemia (FA) genes, including FANCD2, and FANCA, appear to be involved in G2/M phase checkpoint maintenance as well as spindle checkpoint in response to internal and external signals, such as taxane treatment. Thus, we hypothesized that variants in FA genes could impact severity of taxane-induced neuropathies.Methods: Using DNA extracted from blood collected from 893 breast cancer patients participating in a trial evaluating metronomic dosing of cyclophosphamide, doxorubicin and paclitaxel (S0221), we genotyped for single nucleotide polymorphisms (SNPs) that represent all of the variability across FANCA (44 SNPs) and FANCD2 (24 SNPs) in all race/ethnicity groups, as well as a panel of ancestry informative markers to control for potential population stratification, using Illumina GoldenGate platform. SNPs with minor allele frequency (MAF) less than 0.10 and those out of Hardy Weinberg Equilibrium (HWE) proportions (p<0.001) were removed from analyses. Ordinal regression was used to test for allelic and haplotypic association with grade 3 or 4 toxicities relative to 0, 1, and 2 toxicities, adjusting for age, genetic admixture index and treatment arm. To adjust for multiple testing, permutation analyses were performed on both single SNP and haplotype models.Results: Eighteen SNPs in FANCD2 and 38 SNPs in FANCA passed MAF and HWE proportion requirements. For FANCD2, 4 SNPs spanning 67.5 Kb (rs7648104, rs2272125 [coding SNP], rs6786638 and rs644215), were significantly associated with taxane-induced neuropathy (p<0.001) after controlling for multiple testing, with each SNP resulting in approximately a twofold increase in odds of severe taxane-induced neuropathy. Haplotype estimation showed that all 18 SNPs comprise a single haplotype. Two major (>1% frequency) haplotypes were found. The frequencies of the risk haplotype in cases (patients with grade 3 or 4 neuropathy) and controls (patients with ≤ grade 2 neuropathy) were 0.25 and 0.15, respectively. Ordinal regression analyses were highly significant (p<0.0005); patients with at least one copy of the risk haplotype had more than a twofold increased risk of grade 3 or 4 taxane-induced neuropathy (OR=2.2, 95% CI 1.44, 3.44). For FANCA, no SNPs or haplotypes were significantly associated with grade 3 or 4 neurotoxicity, either prior to or after correction for multiple testing.Conclusions: These results indicate that the Fanconi-Anemia pathway may be important for neurological sensitivity to taxanes, and that genotypic markers might be able to be used to identify patients at increased risk for severe taxane-induced neuropathy. Further studies will elucidate potential associations with survival outcomes. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2001.

Purpose Southwest Oncology Group (SWOG)/Intergroup study 9623 was undertaken to compare treatment with an anthracycline-based adjuvant chemotherapy regimen followed by high-dose chemotherapy (HDC) with autologous hematopoietic progenitor cell support (AHPCS) with a modern dose-dense dose-escalated (nonstandard) regimen including both an anthracycline and a taxane. Patients and Methods Participants in this phase III randomized study had operable breast cancer involving four or more axillary lymph nodes and had completed mastectomy or breast-conserving surgery. Patients were randomly assigned to receive four cycles of doxorubicin and cyclophosphamide followed by HDC with AHPCS or to receive sequential dose-dense and dose-escalated chemotherapy with doxorubicin, paclitaxel, and cyclophosphamide. The primary end point of this study was disease-free survival (DFS). Results Among 536 eligible patients, there was no significant difference between the two arms for DFS or overall survival (OS). Estimated five-year DFS was 80% (95% CI, 76% to 85%) for dose-dense therapy and 75% (95% CI, 69% to 80%) for transplantation. Estimated 5-year OS was 88% (95% CI, 84% to 92%) for dose-dense therapy and 84% (95% CI, 79% to 88%) for transplantation. Conclusion There is no evidence that transplantation was superior to dose-dense dose-escalated therapy. Transplantation was associated with an increase in toxicity and a possibly inferior outcome, although the hazard ratios were not significantly different from 1.