The Role of CD4/6 Inhibitors in Breast Cancer Treatment.

Over the last decade, treatment paradigms for breast cancer have undergone a renaissance, particularly in hormone-receptor-positive/HER2-negative breast cancer. These revolutionary therapies are based on the selective targeting of aberrancies within the cell cycle. This shift towards targeted therapies has also changed the landscape of disease monitoring. In this article, we will review the fundamentals of cell cycle progression in the context of the new cyclin-dependent kinase inhibitors. In addition to discussing the currently approved cyclin-dependent kinase inhibitors for breast cancer, we will explore the ongoing development and search for predictive biomarkers and modalities to monitor treatment.

Using cfRNA as a tool to evaluate clinical treatment outcomes in patients with metastatic lung cancers and other tumors.

Aim: We report an exploratory analysis of cfRNA as a biomarker to monitor clinical responses in non-small cell lung cancer (NSCLC), breast cancer, and colorectal cancer (CRC). An analysis of cfRNA as a method for measuring PD-L1 expression with comparison to clinical responses was also performed in the NSCLC cohort. Methods: Blood samples were collected from 127 patients with metastatic disease that were undergoing therapy, 52 with NSCLC, 50 with breast cancer, and 25 with CRC. cfRNA was purified from fractionated plasma, and following reverse transcription (RT), total cfRNA and gene expression of PD-L1were analyzed by real-time polymerase chain reaction (qPCR) using beta-actin expression as a surrogate for relative amounts of cfDNA and cfRNA. For the concordance study of liquid biopsies and tissue biopsies, the isolated RNA was analyzed by RNAseq for the expressions of 13 genes. We had to close the study early due to a lack of follow-up during the Covid-19 pandemic. Results: We collected a total of 373 blood samples. Mean cfRNA PCR signals after RT were about 50-fold higher than those of cfDNA. cfRNA was detected in all patients, while cfDNA was detected in 88% of them. A high concordance was found for the expression levels of 13 genes between blood and solid tumor tissue. Changes in cfRNA levels followed over the course of treatments were associated with response to therapy, increasing in progressive disease (PD) and falling when a partial response (PR) occurred. The expression of PD-L1 over time in patients treated with immunotherapy decreased with PR but increased with PD. Pre-treatment levels of PD-L1 were predictive of response in patients treated with immunotherapy. Conclusion: Changes in cfRNA correlate with clinical response to the therapy. Total cfRNA may be useful in predicting clinical outcomes. PD-L1 gene expression may provide a biomarker to predict response to PD-L1 inhibition.

A Phase II Open Label Study of Everolimus in Combination With Endocrine Therapy in Resistant Hormone Receptor-Positive HER2-Negative Advanced Breast Cancer.

BACKGROUND: Therapies targeting estrogen receptor signaling are standard for patients with hormone receptor (HR)-positive (HR+) metastatic breast cancer (MBC). Dysregulation of the phosphoinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is associated with treatment resistance. Addition of the mTOR inhibitor, everolimus, to exemestane doubled progression-free survival (PFS) in HR+/HER2- MBC patients whose disease had previously progressed during endocrine therapy. In this phase II study, we used everolimus in addition to the most recent endocrine therapy during which a patient's disease progressed, in an attempt to restore and extend the benefit of the antiestrogen therapy in patients with HR+/HER2- MBC. PATIENTS AND METHODS: Patients with HR+ MBC who progressed on antiestrogen therapy received everolimus (10 mg orally daily) in combination with the antiestrogen therapy most recently administered. Treatment was administered in 4-week cycles and continued until disease progression or unacceptable toxicity. Blood and archival tumor specimens were collected for VeriStrat (Biodesix, Inc) and Foundation One (Foundation Medicine) assays, respectively. Accrual of 42 evaluable patients allowed detection of improvement in median PFS from 2.8 months (expected with hormonal treatment alone) to 5 months (power 80%, α = 5%). RESULTS: Forty-seven patients were enrolled and treated. After a median follow-up of 22.2 months, median PFS was 6.6 months. Secondary efficacy end points included: overall response rate, 6%; clinical benefit rate, 40%; and median overall survival, 21.1 months. No unexpected toxicity was observed. Efficacy could not be correlated with PI3K/AKT/mTOR alterations or VeriStrat (Biodesix, Inc) prognostic signatures. CONCLUSION: After progression during antiestrogen therapy, the addition of everolimus, without changing the hormonal therapy, resulted in a median PFS of 6.6 months, suggesting efficacy in patients with HR+/HER2- MBC.

Efficacy and safety of palbociclib plus endocrine therapy in North American women with hormone receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer.

Palbociclib is a cyclin-dependent kinase 4/6 inhibitor indicated for treatment of hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer in combination with endocrine therapy. We investigated the efficacy and safety of palbociclib in patients enrolled in North America during two-phase 3 trials: PALOMA-2 (n = 267, data cutoff: May 31, 2017) and PALOMA-3 (n = 240, data cutoffs: April 13, 2018, for overall survival, October 23, 2015, for all other outcomes). In PALOMA-2, treatment-naïve postmenopausal patients with advanced breast cancer were randomized 2:1 to palbociclib (125 mg/d; 3 weeks on/1 week off [3/1]) plus letrozole (2.5 mg/d, continuous) or placebo plus letrozole. In PALOMA-3, patients who progressed on prior endocrine therapy were randomized 2:1 to palbociclib (125 mg/d; 3/1) plus fulvestrant (500 mg, per standard of care) or placebo plus fulvestrant; pre/perimenopausal patients received ovarian suppression with goserelin. Palbociclib plus endocrine therapy prolonged median progression-free survival vs placebo plus endocrine therapy in North American patients (PALOMA-2: 25.4 vs 13.7 months, hazard ratio, 0.54 [95% CI, 0.40-0.74], P < .0001; PALOMA-3: 9.9 vs 3.5 months, hazard ratio, 0.52 [95% CI, 0.38-0.72], P < .0001). Objective response and clinical benefit response rates were greater with palbociclib vs placebo in North American patients in both trials. While overall survival data are not yet mature for PALOMA-2, median overall survival was increased in PALOMA-3 (32.0 vs 24.7 months, hazard ratio, 0.75 [95% CI, 0.53-1.04]), though this did not reach statistical significance (P = .0869). Safety profiles in North American patients were similar to those of the overall populations; neutropenia was the most common treatment-emergent adverse event. No new safety signals were observed. In summary, palbociclib plus endocrine therapy is an effective treatment option for North American women with hormone receptor-positive/human epidermal growth factor receptor 2-negative advanced breast cancer.

Progression-free Survival Outcome Is Independent of Objective Response in Patients With Estrogen Receptor-positive, Human Epidermal Growth Factor Receptor 2-negative Advanced Breast Cancer Treated With Palbociclib Plus Letrozole Compared With Letrozole: Analysis From PALOMA-2.

BACKGROUND: In PALOMA-2, palbociclib + letrozole significantly prolonged progression-free survival (PFS) versus placebo + letrozole in patients with estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) advanced breast cancer (ABC). We investigated clinical outcomes of patients who achieved or did not achieve a confirmed objective response (OR) according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 (data cutoff: May 31, 2017). PATIENTS AND METHODS: Postmenopausal patients untreated for ER+/HER2- ABC were randomized 2:1 to palbociclib + letrozole or placebo + letrozole. Median PFS, median duration of OR, baseline characteristics, and palbociclib exposure were compared in patients with or without OR by treatment arm. RESULTS: In the intent-to-treat population, OR was achieved by 194 (44%) of 444 and 77 (35%) of 222 patients in the palbociclib and placebo arms, respectively (odds ratio, 1.5; 95% confidence interval [CI], 1.0-2.1; P = .0156). Regardless of treatment, more OR than non-OR patients had de novo metastatic disease (47%-50% and 28%-31%, respectively) and no prior endocrine therapy (55% and 35%-37%, respectively). Rates of palbociclib dose reduction owing to adverse events were similar regardless of OR (41% and 38%, respectively). Among the patients with OR during the study, approximately 50% achieved OR within the first 3 months regardless of treatment. The median PFS was significantly prolonged with palbociclib + letrozole versus placebo + letrozole in patients with measurable disease in both OR (37.2 months; 95% CI, 28.1 months to not estimable vs. 27.4 months; 95% CI, 22.2-31.1 months; hazard ratio, 0.66; 95% CI, 0.47-0.94; P = .009) and non-OR groups (10.9 months; 95% CI, 8.2-11.2 months vs. 5.6 months; 95% CI, 5.3-8.3 months; hazard ratio, 0.72; 95% CI, 0.54-0.97; P = .016). CONCLUSIONS: Palbociclib + letrozole provided significant clinical benefit versus placebo + letrozole to patients with ER+/HER2- ABC regardless of achieving RECIST-defined OR. Pfizer; ClinicalTrials.gov: NCT01740427.

Phase Ib/II single-arm trial evaluating the combination of everolimus, lapatinib and capecitabine for the treatment of HER2-positive breast cancer with brain metastases (TRIO-US B-09).

BACKGROUND: Improving outcomes for patients with human epidermal growth factor 2-positive (HER2+) central nervous system (CNS) metastases remains an unmet clinical need. This trial evaluated a novel combination of everolimus, lapatinib and capecitabine for this disease. METHODS: Patients with trastuzumab-pretreated, HER2+ breast cancer brain metastasis without prior therapy with a mammalian target of rapamycin (mTOR) inhibitor were eligible. Patients received lapatinib and everolimus daily (continuously) and capecitabine twice daily (d1-14) in 21-d cycles. The primary endpoint was the 12-week CNS objective response rate (ORR). Secondary endpoints included safety, progression-free survival (PFS), overall survival (OS), best CNS ORR and extra-CNS ORR. RESULTS: A total of 19 participants were enrolled and treated with ⩾1 dose of the study drug. The median age was 58.5 years, the median number of therapies for metastatic breast cancer was 2.5 (0-11). Pretrial, 74% of participants had received prior lapatinib, capecitabine or both. A total of 63% had received previous CNS radiation or surgical resection and CNS radiation. The maximum tolerated doses were lapatinib at 1000 mg, everolimus at 10 mg, and capecitabine at 1000 mg/m2. Phase II proceeded with capecitabine at 750 mg/m2 due to better tolerability. The most common grade 3/4 adverse events were mucositis (16%), diarrhea, fatigue, and hypokalemia (11% each). Of 11 participants evaluable for 12-week CNS ORR, 3 (27%) had partial response and 7 (64%) had stable disease. The best CNS ORR in eligible participants was 28% (5/18). The median PFS and OS were 6.2 and 24.2 months, respectively. CONCLUSIONS: This novel triplet combination of lapatinib, everolimus, and capecitabine is well tolerated and yielded a 27% response rate in the CNS at 12 weeks in heavily pretreated participants. Larger studies are warranted to further evaluate this regimen. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01783756. Registered 05 February 2013, https://clinicaltrials.gov/ct2/show/NCT01783756.

Evaluation of weekly paclitaxel plus carboplatin followed by anthracycline chemotherapy on the neoadjuvant treatment of patients with triple-negative breast cancer.

OBJECTIVE: To evaluate the effectiveness and tolerability of neoadjuvant chemotherapy with weekly paclitaxel in combination with weekly carboplatin area under curve 2 followed by anthracycline chemotherapy. PATIENTS AND METHODS: This is a retrospective review of electronic medical records of patients (N = 32) with stage 1c-III triple-negative breast cancer. Patients received neoadjuvant chemotherapy with paclitaxel 80 mg/m2 once per week for 12 weeks in combination with carboplatin area under curve 2 once per week for 12 weeks (wP + wCb), followed by a standard anthracycline regimen including either doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2 every 2 or 3 weeks, or epirubicin 90 mg/m2 and cyclophosphamide 600 mg/m2 every 3 weeks for four cycles with myeloid growth factor support. RESULTS: Most patients (91%) received all 12 cycles of wP + wCb, and 88% received all four planned cycles of anthracycline chemotherapy. Of the patients, 84% completed all planned therapies. The complete pathologic response rate was 60%. In terms of hematologic toxicity, 96% of the patients experienced grade ≥3 leucopenia, 40% grade ≥3 anemia, and 15% grade ≥3 thrombocytopenia, and neutropenic fever was seen in 22% of the patients. CONCLUSION: The combination of neoadjuvant chemotherapy with wP + wCb before anthracycline chemotherapy can be tolerated by patients with triple-negative breast cancer. Complete pathologic response rates were comparable with those historically seen. Careful selection of patients is fundamental as this regimen is associated with a high incidence of hematologic toxicity.

Stereotactic Radiosurgery and Ipilimumab Versus Stereotactic Radiosurgery Alone in Melanoma Brain Metastases.

Benefits of stereotactic radiosurgery (SRS) have been well established in melanoma brain metastases (MBM). Immunotherapy agents such as ipilimumab (ipi) have recently demonstrated clinical efficacy in advanced disease as well. The theoretical synergistic effects of combining these therapies in MBM have not been explored in detail, however, we conducted a systematic review with meta-analysis of studies that compared combined SRS and ipi versus SRS alone in MBM. Medical Literature Analysis and Retrieval System Online (MEDLINE) and Central databases were used for our literature search, which was conducted by three reviewers. We included studies that examined SRS and ipilimumab compared to SRS alone in MBM. Pertinent results were tabulated in a standardized spreadsheet. Newcastle-Ottawa Scale (NOS) Risk of Bias Assessment and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) method for rating evidence quality were used for qualitative analysis. Review Manager was used for statistical analysis. We identified four cohort studies that compared SRS plus ipi versus SRS alone in MBM. As per the GRADE criteria, we found low-quality evidence for survival benefits associated with combined treatment. Meta-analysis confirmed a significant benefit in survival for SRS and ipilimumab (hazard ratio 0.38, 95% confidence interval 0.28 - 0.52, p < 0.01). There were no significant differences between comparison groups for local control, distant brain control, radiation necrosis, or intracranial bleeding. We conclude that low-quality evidence exists for superior overall survival in MBM treated with SRS and ipilimumab compared to SRS without ipilimumab. There is also no increased risk of radiation necrosis and/or intracranial bleeding with combining radiation and immunotherapy in this setting.

Impressive Response to Concomitant Platinum-based Chemotherapy and Yttrium-90 in a Patient with Heavily Pretreated Triple-negative Breast Cancer Widely Metastasized to the Liver.

Metastatic triple-negative breast cancer (TNBC) constitutes a heterogeneous group of diseases with systemic treatment options limited to cytotoxic chemotherapy at the time being. The disease tends to affect visceral organs more frequently when compared to hormone receptor-positive breast cancer. The prognoses of patients with heavily pretreated disease affecting the liver are very dismal. We present the response to radioembolization and systemic chemotherapy in a seriously ill patient who had undergone previous lines of chemotherapy for TNBC with extensive liver metastases.

Novel Strategies to Improve the Endocrine Therapy of Breast Cancer.

Endocrine therapy (ET) constitutes the usual first-line of therapy for patients in the treatment of metastatic hormone receptor-positive breast cancer. Unfortunately, not all patients respond to first-line endocrine treatment due to intrinsic resistance, while others may initially respond but eventually progress with secondary acquired resistance leading to disease progression. Mechanisms of resistance to anti-estrogen therapy include, loss of expression for estrogen or progesterone receptor, upregulation of epidermal receptor growth factor 2, increased receptor tyrosine kinase signaling, leading to activation of various intracellular pathways that are involved in signal transduction such as PI3K/AKT/mammalian target of rapamycin, and others. Growing understanding of the signal cascade of estrogen receptors and the signaling pathways that interact with estrogen receptors has revealed the complex role of these receptors in cell growth and proliferation, and on the mechanism in development of resistance. These insights have led to the development of targeted therapies that may prove to be effective options for the treatment of breast cancer and may overcome hormone therapy resistance. In this review we summarize some of the mechanisms of endocrine resistance, selected clinical trials of ET and targeted therapies, which might interfere with estrogen receptor pathways and might reduce or reverse resistance to traditional, sequential, single-agent ET.

The Role of Carboplatin in the Neoadjuvant Chemotherapy Treatment of Triple Negative Breast Cancer.

Triple negative breast (TNBC) cancer constitutes a heterogeneous group of disease with histologic and molecular differences. Complete pathologic response to neoadjuvant chemotherapy (NACT) in TNBC is associated with improved outcomes. Efforts have been made in identifying drug combinations that will increase the response rate to preoperative chemotherapy. In this review we present recent studies that have incorporated carboplatin (Cb) in the NACT of TNBC. We discuss the homologous recombination deficiency score and the somatic or germline mutation for BRCA as potential biomarkers for future selection of patients that could benefit from the addition of Cb to NACT.

Final results of a phase II study of nab-paclitaxel, bevacizumab, and gemcitabine as first-line therapy for patients with HER2-negative metastatic breast cancer.

In order to examine the efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-P) in combination with bevacizumab (B) and gemcitabine (G) for the first-line treatment of patients with HER2-negative metastatic breast cancer (MBC). In this single-center, open-label phase II trial, patients with HER2-negative MBC received gemcitabine 1500 mg/m(2), nab-paclitaxel 150 mg/m(2), and bevacizumab 10 mg/kg (each administered intravenously) on days 1 and 15 of a 28-day cycle. The primary end point was progression free survival (PFS); secondary end points were overall response rate (ORR), complete (CR) and partial (PR) response rates, clinical benefit (ORR + stable disease), overall survival (OS), and safety. Thirty patients were enrolled. One patient was ineligible and was not included in analysis. Median PFS was 10.4 months (95% CI: 5.6-15.2 months). ORR was 75.9%, comprising eight (27.6%) CRs and 14 (48.3%) PRs; five patients had stable disease (SD) and two patients (6.9%) had progressive disease (PD) as their best response. The clinical benefit rate was 93.1% (27/29) in the overall group and 84.6% in the triple-negative cohort (11/13). The 18-month survival rate was 77.2% (95% CI: 51.1-90.5%). Eight (27.6%) patients experienced grade 3 or 4 toxicity: grade 4 neutropenic fever (n = 1) and grade 3 infection (n = 6), leukopenia, thrombocytopenia, peripheral neuropathy, seizure, shortness of breath, hematuria, and cardiac tamponade (one each). First-line therapy with nab-P, B, and G demonstrated a median PFS of 10.4 months and a 75.9% ORR with acceptable toxicity; this novel combination warrants investigation in a randomized study.

Nasopharyngeal carcinoma: alternative treatment options after disease progression.

Nasopharyngeal carcinoma is a rare malignancy with an incidence well under one per 100,000 person-years, except for some geographic areas, such as Asia. The prognosis of nasopharyngeal carcinoma is related to its potential for locoregional invasion and metastatic spread. Radiotherapy alone remains the standard treatment for early stages. However, for locally advanced disease, chemotherapy may offer some benefit as a radiosensitizer while treating microscopic spread disease. Chemoradiotherapy is now the standard treatment for locally advanced and/or node-positive patients. Platinum-based therapy is the preferred regimen for this therapeutic approach. In this review, we discuss all treatment modalities available for nasopharyngeal carcinoma, including the standard of care and what therapeutic options could be available for those patients who progress after the standard treatment has been delivered.

Crohn's disease complicated by primary gastrointestinal Hodgkin's lymphoma presenting with small bowel perforation.

An increased incidence of non-Hodgkin's lymphoma has been reported in patients with inflammatory bowel disease, particularly in those receiving immunosuppressive therapy. Rare cases of Hodgkin;s lymphoma have been reported in a setting of inflammatory bowel disease. The mechanism underlying the apparent association is unclear, but alterations in immune surveillance could play a role. In this report we describe the clinicopathological features of primary gastrointestinal Hodgkin's lymphoma diagnosed in a patient with Crohn's ileocolitis who had been receiving therapy with immunomodulator and biologic therapies.

Second-line therapy for non-small-cell lung cancer.

Carcinogenesis is a complex pathological process induced by abnormalities in the genome, cell-cycle dysregulation, loss of the programmed cell death process, and upregulation of oncogenic pathways associated with proliferation, migration, and survival, among others. Despite recent advances in molecular and tumor biology in non-small-cell lung cancer (NSCLC) and the introduction of several targeted agents, the disease continues to have a dismal survival. Nonetheless, the future looks promising; conventional cytotoxic chemotherapy regimens in combination with targeted agents have shown better response rates and survival than those seen in the past. These targeted agents have the advantage of blocking or inhibiting specific pathways necessary for tumor growth, proliferation, and metastases, without significantly affecting quality of life by having an acceptable toxicity profile. Thus, these novel agents harbor a hope in the treatment of NSCLC and many other malignant diseases when they can be used either in combination with other chemotherapy drugs in several lines of treatment or as a single agent in maintenance therapy until progression of disease, or even more attractively, in combination with other targeted agents themselves. In this review, we discuss second-line treatments for patients who have NSCLC, including targeted agents and their development in this specific setting as part of our armamentarium in lung cancer.

Lapatinib plus capecitabine resolved human epidermal growth factor receptor 2-positive brain metastases.

Brain metastases affect 25%-30% of women with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer and are associated with a high burden of disease and poor prognosis. A 55-year-old woman presented with HER2-positive, hormone receptor-positive, locally advanced infiltrating ductal carcinoma. She received 4 cycles of neoadjuvant docetaxel (75 mg/m) plus trastuzumab (6 mg/kg) on a 21-day cycle, resulting in complete pathologic response at the time of surgery. Trastuzumab (6 mg/kg every 21 days) plus anastrozole (1 mg/d) was continued for 1 year. Two years later, the patient progressed with pulmonary nodules and a large pleural effusion. Computed tomography and positron emission tomography revealed multiple lesions in the liver and thoracic spine but no evidence of brain metastases. The patient received weekly trastuzumab (2 mg/kg), paclitaxel (80 mg/m), and carboplatin (area under the curve 2) for 6 months; her symptoms resolved and her disease stabilized. Seven months later, she developed diplopia and gait difficulties, and magnetic resonance imaging revealed multiple brain lesions. Whole-brain radiotherapy (30 Gy in 10 fractions) was delivered with excellent clinical results. The patient remained progression free without symptoms for approximately 3 months. When she developed central nervous system symptoms, she was treated with lapatinib (1250 mg/d continuously) plus capecitabine (2000 mg/m given on days 1-14 of a 21-day cycle). Four months later, a brain computed tomography performed shortly before her death from progressive systemic disease revealed near complete resolution of brain metastases. Lapatinib plus capecitabine seems to have clinical activity in HER2-positive brain metastases.

Controversies in the management of stage IIIA non-small-cell lung cancer.

New developments in the management of non-small-cell lung cancer, as well as recent proposals for changing the current lung cancer staging system, are posing a challenge in the therapeutic decision making regarding this disease. For the last two decades, the management of stage IIIA (N2) disease has been controversial and the target for clinical trials has been to determine the best therapeutic approach that may result in better survival outcomes without increasing toxicity. For many years, combined modality treatment (systemic chemotherapy plus radiation therapy) became the standard of care in this setting. However, the poor outcomes seen with combined modality for N2 has obligated us to explore other possibilities. In this sense, recent clinical trials in the neoadjuvant setting using chemotherapy alone or combined modality are providing fruitful results and shifting the paradigm on this stage. A recent, large randomized multicenter trial argues against what has slowly become a current practice in some centers - the use of preoperative modality for N2 disease. Another controversy that we will discuss here is the acceptance of adjuvant therapy for resected stage IB-IIIA non-small-cell lung cancer. It was not long ago that adjuvant radiation therapy was still the standard of care for patients who have pathological nodal disease. We will present the current data on these debatable issues and how to implement this new knowledge into clinical practice.

Adjuvant therapy for HER2 positive breast cancer: are anthracyclines still necessary?

Anthracyclines are integral components of most adjuvant chemotherapy regimens for surgically removed early breast cancer and are central to the accepted treatment standards. Recently the standard anthracycline regimen of doxorubicin plus cyclophosphamide was found to be inferior in preventing recurrence of breast cancer when compared to cyclophosphamide and docetaxel, questioning the necessity to expose patients to the potential cardiotoxicity of anthracycline in the adjuvant setting. Trastuzumab, a humanized monoclonal antibody against the extracellular domain of the human epidermal growth factor receptor 2 (HER2) has become the cornerstone of treatment of breast cancers that overexpress HER2 in the neo-adjuvant and metastatic setting. Unfortunately, the combination of anthracyclines and trastuzumab produces a high incidence of cardiotoxicity as seen in early trials of metastatic breast cancer. Five adjuvant trials combining trastuzumab with different anthracycline-based regimens have been reported, all of them revealing similar efficacy in reducing recurrence of breast cancer. The trastuzumab adjuvant trial 006 from the Breast Cancer International Research Group shows for the first time that a nonanthracycline-containing regimen with trastuzumab has equivalent efficacy in decreasing the recurrence of breast cancer, with less incidence of cardiotoxicity when compared to anthracycline-containing trastuzumab adjuvant regimens. Further trials are needed to determine the optimal length of adjuvant therapy with trastuzumab, as well as long-term side effects with special attention to cardiotoxicity.

Chemoprevention of breast cancer.

Breast cancer remains the second leading cause of malignancy-related death in women in the USA, regardless of advances in novel therapeutic agents. High priority should be given to research aimed at the study of pharmacological and natural compounds that could potentially prevent the development of breast cancer in susceptible patients. Tamoxifen has been shown to reduce the incidence of estrogen receptor-positive invasive breast cancer in women with a high risk of developing this condition by nearly 50%, and studies in osteoporosis have revealed a similar protective effect of raloxifene in postmenopausal women. The aromatase inhibitors are superior to tamoxifen in reducing the recurrence of breast cancer in postmenopausal women; large clinical trials are currently evaluating the chemopreventive effect of these agents. The list of agents with the potential for chemoprevention in breast cancer is extensive and continues to expand. There is an immense need to develop drugs that will decrease the incidence of estrogen receptor-negative breast cancer in women at high risk of developing the disease. Herein, we review the most important chemopreventive agents in breast cancer and clinical trials that have evaluated their efficacy.