Breast Cancer

Latest News


CME Content


Why doesn't cisplatin work very well against breast cancer? The first response of most researchers would be to invoke something about genetic responses, but a pair of biologists from the University of Cincinnati have raised a quite different proposalr: The unique hormonal milieu of the breast may contribute to chemoresistance.

The regimented and inflexible protocols that have long served as hallmarks of clinical trials are giving way to personalized medical research. A clinical trial begun last week at the University of California, San Francisco will use genetic and biological markers drawn from the tumors of individual patients to identify the treatments most likely to be effective for those participating in the trial.

Over the past decade, the oncology community has made significant progress in the development of highly effective treatment modalities for breast cancer. Moreover, our increasing knowledge of the molecular biology of cancer has engendered the potential to use gene expression profiling, molecular fingerprinting, and biomarkers to add increased, patient-specific value to our clinical decision making. More than ever, today’s clinician must keep up to date on the rapid scientific advances in breast cancer management.

Next-generation genomic assay technologies are revolutionizing our ability to characterize cancers at the genomic levels, providing critical prognostic and predictive information for individual patients with breast cancer, thereby helping to guide treatment decisions. According to Harold J. Burstein, MD, PhD, Associate Professor of Medicine, Harvard Medical School, these emerging technologies will change the way we treat breast cancer.

For oncologists battling breast cancer in the clinic, one of the most difficult decisions is choosing the optimal adjuvant therapy, one that balances the fine line between efficacy and toxicity. Clifford A. Hudis, MD, Chief, Breast Cancer Medicine Service at Memorial Sloan-Kettering Cancer Center, tackled this difficult clinical discussion in an interview with ONCOLOGY.

Nationally recognized breast cancer specialist Eric P. Winer, MD, presented two lectures at this year’s MBCC, “Strategies for Patients with Refractory HER2-Positive Breast Cancer,” and “Addressing Menopausal Symptoms and Fertility in Breast Cancer.” In an exclusive interview with ONCOLOGY, Dr. Winer explained how hormonal therapy can best be used in the difficult stetting of metastatic disease.

Large clinical trials have demonstrated that preoperative therapy for primary operable breast cancer improves breast-conservation rates, with equivalent disease-free (DFS) and overall survival (OS) compared to adjuvant therapy.[1] Connolly and Stearns provide an excellent review of additional benefits of neoadjuvant therapy and emphasize the importance of a multidisciplinary approach to treating patients in this setting.

Agendia, a leader in molecular cancer diagnostics, recently announced that the US Food and Drug Administration (FDA) cleared its MammaPrint breast cancer recurrence test for all ages. MammaPrint is the only FDA-cleared breast cancer recurrence test available to patients and physicians. Over the past 3 years, the FDA has issued four clearances for MammaPrint, covering all aspects of this service.

Pharmacologic strategies targeting the DNA of tumor cells have been in use for much of the past century for many different cancer types. Radiation has also been a long-employed strategy to cause DNA damage and subsequent tumor cell death. However, the class of agents designed to inhibit the enzyme poly-(ADP-ribose) polymerase (PARP) have taken this a step further-these agents do not damage DNA themselves, but rather, inhibit the repair of DNA via inhibition of the base excision single-strand repair pathway. PARP inhibitors have been shown preclinically and clinically to enhance the affects of chemotherapies known to damage DNA or interefere with DNA replication. However, the most exciting use of PARP inhibitors may be in exploiting the concept of synthetic lethality. In this setting, the concept is based on two factors: (1) BRCA1/2-positive malignancies cannot use one of the major pathways to repair double-strand DNA breaks (ie, homologous recombination), and (2) making the base excision repair pathway nonfunctional via inhibition of PARP leads to tumor cell death, as unrepaired single-strand breaks are converted into double-strand breaks.

In this issue of ONCOLOGY, Comen and Robson provide a timely overview of poly(ADP-ribose) polymerase (PARP) inhibitors and their potential for the treatment of breast cancer. The authors highlight the recent demonstration of synthetic lethality between PARP inhibition and loss of either of the breast cancer susceptibility genes, BRCA1 and BRCA2, as well as the development of PARP inhibitors that are suitable for clinical therapy. However, many questions pertaining to both the basic biology of PARP inhibition and the potential clinical implications of PARP inhibitors still need to be addressed. In the following commentary, we highlight some of these remaining challenges.

As knowledge increases about the processes underlying cancer, it is becoming feasible to design “targeted therapies” directed toward specific pathways that are critical to the genesis or maintenance of the malignant phenotype. Poly(ADP-ribose) polymerase (PARP) inhibitors are an example of this new framework. DNA damage repair is a complex and multifaceted process that is critical to cell survival. Members of the PARP family are central to specific DNA damage repair pathways, particularly the base excision repair (BER) pathway. PARP inhibition, with subsequent impairment of the BER mechanism, may enhance the cytotoxicity of agents that generate single-strand breaks in DNA, such as radiation and certain chemotherapy drugs. In addition, PARP inhibitors may induce death through “synthetic lethality” if the DNA repair mechanisms that rescue BER-deficient cells are themselves impaired. This mechanism is thought to underlie the impressive results of PARP inhibition in BRCA-associated breast and ovarian cancer, and may also account for the reported benefit of this approach in “triple-negative” breast cancer. This review will examine the current understanding of PARP inhibition as a treatment for breast cancer, ongoing clinical trials, and future directions for this new approach.