Rebecca Dent

Triple-Negative Breast Cancer: Clinical Features and Patterns of Recurrence

Purpose: To compare the clinical features, natural history, and outcomes for women with “triple-negative” breast cancer with women with other types of breast cancer. Experimental Design: We studied a cohort of 1,601 patients with breast cancer, diagnosed between January 1987 and December 1997 at Womens College Hospital in Toronto. Triple-negative breast cancers were defined as those that were estrogen receptor negative, progesterone receptor negative, and HER2neu negative. The prognostic significance of triple-negative breast cancer was explored. Results: The median follow-up time of the 1,601 women was 8.1 years. One hundred and eighty of 1,601 patients (11.2%) had triple-negative breast cancer. Compared with other women with breast cancer, those with triple-negative breast cancer had an increased likelihood of distant recurrence (hazard ratio, 2.6; 95% confidence interval, 2.0-3.5; P < 0.0001) and death (hazard ratio, 3.2; 95% confidence interval, 2.3-4.5; P < 0.001) within 5 years of diagnosis but not thereafter. The pattern of recurrence was also qualitatively different; among the triple-negative group, the risk of distant recurrence peaked at ∼3 years and declined rapidly thereafter. Among the “other” group, the recurrence risk seemed to be constant over the period of follow-up. Conclusions: Triple-negative breast cancers have a more aggressive clinical course than other forms of breast cancer, but the adverse effect is transient.

Pathologic Complete Response Rates in Young Women With BRCA1-Positive Breast Cancers After Neoadjuvant Chemotherapy

PURPOSE To estimate the rate of pathologic complete response (pCR) to neoadjuvant chemotherapy in BRCA1 mutation carriers according to chemotherapy regimen. PATIENTS AND METHODS From a registry of 6,903 patients, we identified 102 women who carried a BRCA1 founder mutation and who had been treated for breast cancer with neoadjuvant chemotherapy. Pathologic complete response was evaluated using standard criteria. RESULTS Twenty-four (24%) of the 102 BRCA1 mutation carriers experienced a pCR. The response rate varied widely with treatment: a pCR was observed in one (7%) of 14 women treated with cyclophosphamide, methotrexate, and fluorouracil (CMF); in two (8%) of 25 women treated with doxorubicin and docetaxel (AT); in 11 (22%) of 51 women treated with doxorubicin and cyclophosphamide (AC) or fluorouracil, doxorubicin, and cyclophosphamide (FAC), and in 10 (83%) of 12 women treated with cisplatin. CONCLUSION A low rate of pCR was observed in women with breast cancer and a BRCA1 mutation who were treated with AT or CMF. A high rate of pCR was seen after treatment with cisplatin. An intermediate rate of PCR was associated with AC or FAC. The relative benefits of AC and platinum therapy need to be confirmed through follow-up of this and other cohorts.

Adjuvant bevacizumab-containing therapy in triple-negative breast cancer (BEATRICE): primary results of a randomised, phase 3 trial

BACKGROUND The addition of bevacizumab to chemotherapy improves progression-free survival in metastatic breast cancer and pathological complete response rates in the neoadjuvant setting. Micrometastases are dependent on angiogenesis, suggesting that patients might benefit from anti-angiogenic strategies in the adjuvant setting. We therefore assessed the addition of bevacizumab to chemotherapy in the adjuvant setting for women with triple-negative breast cancer. METHODS For this open-label, randomised phase 3 trial we recruited patients with centrally confirmed triple-negative operable primary invasive breast cancer from 360 sites in 37 countries. We randomly allocated patients aged 18 years or older (1:1 with block randomisation; stratified by nodal status, chemotherapy [with an anthracycline, taxane, or both], hormone receptor status [negative vs low], and type of surgery) to receive a minimum of four cycles of chemotherapy either alone or with bevacizumab (equivalent of 5 mg/kg every week for 1 year). The primary endpoint was invasive disease-free survival (IDFS). Efficacy analyses were based on the intention-to-treat population, safety analyses were done on all patients who received at least one dose of study drug, and plasma biomarker analyses were done on all treated patients consenting to biomarker analyses and providing a measurable baseline plasma sample. This trial is registered with ClinicalTrials.gov, number NCT00528567. FINDINGS Between Dec 3, 2007, and March 8, 2010, we randomly assigned 1290 patients to receive chemotherapy alone and 1301 to receive bevacizumab plus chemotherapy. Most patients received anthracycline-containing therapy; 1638 (63%) of the 2591 patients had node-negative disease. At the time of analysis of IDFS, median follow-up was 31·5 months (IQR 25·6-36·8) in the chemotherapy-alone group and 32·0 months (27·5-36·9) in the bevacizumab group. At the time of the primary analysis, IDFS events had been reported in 205 patients (16%) in the chemotherapy-alone group and in 188 patients (14%) in the bevacizumab group (hazard ratio [HR] in stratified log-rank analysis 0·87, 95% CI 0·72-1·07; p=0·18). 3-year IDFS was 82·7% (95% CI 80·5-85·0) with chemotherapy alone and 83·7% (81·4-86·0) with bevacizumab and chemotherapy. After 200 deaths, no difference in overall survival was noted between the groups (HR 0·84, 95% CI 0·64-1·12; p=0·23). Exploratory biomarker assessment suggests that patients with high pre-treatment plasma VEGFR-2 might benefit from the addition of bevacizumab (Cox interaction test p=0·029). Use of bevacizumab versus chemotherapy alone was associated with increased incidences of grade 3 or worse hypertension (154 patients [12%] vs eight patients [1%]), severe cardiac events occurring at any point during the 18-month safety reporting period (19 [1%] vs two [<0·5%]), and treatment discontinuation (bevacizumab, chemotherapy, or both; 256 [20%] vs 30 [2%]); we recorded no increase in fatal adverse events with bevacizumab (four [<0·5%] vs three [<0·5%]). INTERPRETATION Bevacizumab cannot be recommended as adjuvant treatment in unselected patients with triple-negative breast cancer. Further follow-up is needed to assess the potential effect of bevacizumab on overall survival.

Response to neoadjuvant therapy with cisplatin in BRCA1-positive breast cancer patients

Background Ten patients with breast cancer and a breast cancer susceptibility gene 1 (BRCA1) mutation, who presented with stages I to III breast cancer between December 2006 and 2007, were treated with four cycles of neoadjuvant cisplatin, followed by mastectomy and conventional chemotherapy. Methods The excised breast tissue and lymph nodes were examined for the presence of residual disease. Results Pathologic complete response was observed in nine patients (90%). Conclusions Platinum-based chemotherapy appears to be effective in a high proportion of patients with BRCA1-associated breast cancers. Clinical trials are now warranted to determine the optimum treatment for this subgroup of breast cancer patients.

Survival outcomes for patients with metastatic triple-negative breast cancer: implications for clinical practice and trial design.

BACKGROUND Clinical experience suggests that many women with triple-negative metastatic breast cancer (MBC) relapse quickly. This has implications for clinical practice and trial design. We evaluated the duration of first-, second-, and third-line chemotherapy as a surrogate for duration of treatment response. PATIENTS AND METHODS We performed a retrospective multicenter chart review of patients with triple-negative MBC receiving palliative chemotherapy. Primary outcome was duration of palliative chemotherapy, and secondary outcome was to identify prognostic variables. RESULTS A total of 111 patients were analyzed. Median age at diagnosis was 51 years (range, 26-82 years). Fourteen percent of patients presented with MBC. Twenty-seven percent received neoadjuvant chemotherapy, and 48% received adjuvant chemotherapy. Median distant disease-free interval (DDFI) was 18 months (range, 0-172 months). At presentation of MBC, 68% had visceral and 71% had multiple sites of disease. Median survival with MBC was 13.3 months (range, 0.8-99.8 months). Median duration of first-line palliative therapy was 11.9 weeks (range, 0-73.1 weeks). Eighty-seven patients (78%) went on to receive second-line therapy with a median duration of 9 weeks (range, 0-120.9 weeks), and 55 (49%) received third-line therapy with a median duration of 4 weeks (range, 0-59 weeks). Multivariate analysis revealed that age < 50 years, ALP > 120 U/L, history of previous chemotherapy, DDFI < 12 months, and visceral presentation were all independently associated with a poor prognosis. CONCLUSION Despite the poorer overall prognosis of patients with triple-negative disease, there remains considerable heterogeneity in individual outcomes. Many women with recurrent triple-negative disease will progress quickly on first-, second-, and third-line palliative treatment. Future clinical trials in this population must take into account their shorter time to progression when determining optimal trial design.

Results of a phase II open-label, non-randomized trial of cisplatin chemotherapy in patients with BRCA1-positive metastatic breast cancer

IntroductionThe purpose of this investigation was to evaluate the efficacy of cisplatin chemotherapy in BRCA1 mutation carriers with metastatic breast cancer.MethodsIn a phase II, open-label study, 20 patients with metastatic breast cancer who carried a mutation in BRCA1 were treated with cisplatin 75 mg/m2 intravenously every 3 weeks as part of a 21-day cycle for 6 cycles. Restaging studies to assess response were performed after cycles 2 and 6, and every three months thereafter.ResultsBetween July 2007 and January 2009, 20 patients were enrolled. Baseline characteristics were as follows: 65% had prior adjuvant chemotherapy, 55% had prior chemotherapy for metastatic breast cancer; mean age was 48 years (ranges 32 to 70); 30% estrogen receptor (ER) or progesterone receptor (PR)+, 70% ER/PR/Human Epidermal Growth Factor Receptor 2 (HER2)- and 0% HER2+. Overall response rate was 80%; nine patients experienced a complete clinical response (45%) and seven experienced a partial response (35%). Overall survival was 80% at one year, 60% at two years and 25% at three years. Four of the 20 patients are alive four years after initiating treatment. The median time to progression was 12 months. The median survival from the start of cisplatinum treatment was 30 months. Cisplatin-related adverse events, including nausea (50%), anemia (5%) and neutropenia (35%) were mostly mild to moderate in severity.ConclusionsThis phase II study demonstrates that cisplatin chemotherapy has high activity in women with a BRCA1 mutation and metastatic breast cancer and is generally well tolerated.Trial registrationThis trial is registered retrospectively on the clinical trials website ClinicalTrials.gov. The identifier is NCT01611727.

Poly(ADP-Ribose) Polymerase Inhibition: “Targeted” Therapy for Triple-Negative Breast Cancer

In contrast to endocrine-sensitive and human epidermal growth factor receptor 2 (HER2)–positive breast cancer, novel agents capable of treating advanced triple-negative breast cancer (TNBC) are lacking. Poly(ADP-ribose) polymerase (PARP) inhibitors are emerging as one of the most promising “targeted” therapeutics to treat TNBC, with the intended “target” being DNA repair. PARPs are a family of enzymes involved in multiple cellular processes, including DNA repair. TNBC shares multiple clinico-pathologic features with BRCA-mutated breast cancers, which harbor dysfunctional DNA repair mechanisms. Investigators hypothesized that PARP inhibition, in conjunction with the loss of DNA repair via BRCA-dependent mechanisms, would result in synthetic lethality and augmented cell death. This hypothesis has borne out in both preclinical models and in clinical trials testing PARP inhibitors in both BRCA-deficient and triple-negative breast cancer. The focus of this review includes an overview of the preclinical rationale for evaluating PARP inhibitors in TNBC, the presumed mechanism of action of this novel therapeutic class, promising results from several influential clinical trials of PARP inhibition in advanced breast cancer (both TNBC and BRCA deficient), proposed mechanisms of acquired resistance to PARP inhibitors, and, finally, concludes with current challenges and future directions for the development of PARP inhibitors in the treatment of breast cancer. Clin Cancer Res; 16(19); 4702–10. ©2010 AACR.

Targeting triple-negative breast cancer: optimising therapeutic outcomes

BACKGROUND Triple-negative breast cancer (TNBC) is a distinct subset of breast cancer (BC) defined by the lack of immunohistochemical expression of the estrogen and progesterone receptors and human epidermal growth factor receptor 2. It is highly heterogeneous and displays overlapping characteristics with both basal-like and BC susceptibility gene 1 and 2 mutant BCs. This review evaluates the activity of emerging targeted agents in TNBC. DESIGN A systematic review of PubMed and conference databases was carried out to identify randomised clinical trials reporting outcomes in women with TNBC treated with targeted and platinum-based therapies. RESULTS AND DISCUSSION Our review identified TNBC studies of agents with different mechanisms of action, including induction of synthetic lethality and inhibition of angiogenesis, growth, and survival pathways. Combining targeted agents with chemotherapy in TNBC produced only modest gains in progression-free survival, and had little impact on survival. Six TNBC subgroups have been identified and found to differentially respond to specific targeted agents. The use of biological preselection to guide therapy will improve therapeutic indices in target-bearing populations. CONCLUSION Ongoing clinical trials of targeted agents in unselected TNBC populations have yet to produce substantial improvements in outcomes, and advancements will depend on their development in target-selected populations.BACKGROUND Triple-negative breast cancer (TNBC) is a distinct subset of breast cancer (BC) defined by the lack of immunohistochemical expression of the estrogen and progesterone receptors and human epidermal growth factor receptor 2. It is highly heterogeneous and displays overlapping characteristics with both basal-like and BC susceptibility gene 1 and 2 mutant BCs. This review evaluates the activity of emerging targeted agents in TNBC. DESIGN A systematic review of PubMed and conference databases was carried out to identify randomised clinical trials reporting outcomes in women with TNBC treated with targeted and platinum-based therapies. RESULTS AND DISCUSSION Our review identified TNBC studies of agents with different mechanisms of action, including induction of synthetic lethality and inhibition of angiogenesis, growth, and survival pathways. Combining targeted agents with chemotherapy in TNBC produced only modest gains in progression-free survival, and had little impact on survival. Six TNBC subgroups have been identified and found to differentially respond to specific targeted agents. The use of biological preselection to guide therapy will improve therapeutic indices in target-bearing populations. CONCLUSION Ongoing clinical trials of targeted agents in unselected TNBC populations have yet to produce substantial improvements in outcomes, and advancements will depend on their development in target-selected populations.

Phase I trial of the oral PARP inhibitor olaparib in combination with paclitaxel for first- or second-line treatment of patients with metastatic triple-negative breast cancer

IntroductionThis Phase I study evaluated the safety, tolerability and efficacy of olaparib, a potent oral poly(ADP-ribose) polymerase (PARP) inhibitor, in combination with paclitaxel in patients with metastatic triple-negative breast cancer (mTNBC).MethodsEligible patients who had received ≤1 prior cytotoxic regimen for mTNBC were treated with olaparib 200 mg bid continuously plus weekly paclitaxel 90 mg/m2 for three weeks per four-week cycle. Dose modifications in a large proportion of patients due to neutropenia resulted in enrollment of a second cohort of patients who, if they experienced grade ≥2 neutropenia in cycle 1, received granulocyte-colony stimulating factor, which was continued prophylactically in subsequent cycles. All patients had measurable disease; tumor responses were evaluated according to RECIST (version 1.0).ResultsNineteen patients (cohort 1, n = 9; cohort 2, n = 10) received treatment; 15 had received prior taxane chemotherapy. The most frequent adverse events were diarrhea (n = 12, 63%), nausea (n = 11, 58%) and neutropenia (n = 11, 58%). Seven neutropenia events were reported in cohort 1 (four grade ≥3) and four in cohort 2 (two grade ≥3, including one event of febrile neutropenia). The median (range) dose intensity of paclitaxel was 57% (26 to 100%) in cohort 1 and 73% (29 to 100%) in cohort 2. Seven patients (37%) had a confirmed partial response; one patient remains on olaparib monotherapy without progression.ConclusionsThe combination of olaparib and weekly paclitaxel was complicated by a significant clinical interaction, with higher-than-expected rates of neutropenia despite secondary prophylaxis. Given the encouraging response rate, alternative scheduling and dosing strategies should be considered (funded by AstraZeneca; ClinicalTrials.gov, NCT00707707).

Patterns of recurrence in the basal and non-basal subtypes of triple-negative breast cancers

Traditional prognostic markers for breast cancer include estrogen receptor (ER), progesterone receptor (ER) and HER2/neu. Negative staining for these three markers defines the ‘triple-negative’ phenotype. By adding markers for cytokeratin 5/6 and EGFR, triple-negative breast cancers can be divided into ‘basal-like’ and ‘normal-like’ subgroups. We conducted immuno-staining on a panel of 958 patients with breast cancer, using all five markers and we followed the patients for distal recurrence and death. We compared rates of distal recurrence in the basal-like and normal-like subgroups with that of women with ER-positive breast cancer. Only 16 of 958 women had normal-like breast cancers. These cancers resembled basal-like cancers in that they had a high proliferative index, but the women with normal-like breast cancers resembled ER-positive women in terms of distant recurrence. The addition of CK5/6 and EGFR to the standard panel (ER/PR/HER2/neu) defines a small subgroup of women with normal-like breast cancer. The prognosis of these women may be superior to that of basal-like breast cancers but firm conclusions cannot be made.