CancerNetwork: Thinking about the continuing challenge of detecting and treating breast cancer, what has been one of the biggest successes in your mind in 2011, in either detection or treatment?
Dr. Osborne: I would say that there are two things. First, another trial has been presented, but I don't think it's been published yet, and that trial looked at another way of preventing breast cancer with the use of a drug called exemestane(Drug information on exemestane) (Aromasin). Of course, tamoxifen(Drug information on tamoxifen) is an anti-estrogen that has been shown to reduce the risk of breast cancer in high-risk individuals by about half. Well, this exemestane drug works by lowering the amount of estrogen in the body in postmenopausal women, so that's another way of treating breast cancer. In this trial, they compared exemestane vs placebo, and exemestane was also highly effective, so this demonstrates how important estrogen is in causing breast cancer or contributing to it. In this study, I think there was a 70% reduction in the risk of acquiring breast cancer.
The biggest problem we're having in the area of breast cancer prevention is in getting high-risk individuals to use drugs like tamoxifen or exemestane. I think the second big thing is the clear demonstration now, in multiple studies, that combining drugs to block HER2 works better than any drug alone, for example trastuzumab(Drug information on trastuzumab) or lapatinib. The next question of course is, do we really need chemotherapy in these patients? In a study that our group presented at ASCO this year, we didn't use chemotherapy. It was a neoadjuvant study, so we could detect how much the tumor shrank, and 12 weeks of lapatinib plus Herceptin resulted in 40% total eradication of the invasive breast cancer from the breast without any chemotherapy at all. So there is probably a group of patients with HER2-positive breast cancer—maybe as many as 40% to 50% of them—who don't need chemotherapy. This remains to be proven in large trials, but the data seem to indicate that we're getting almost as good a result just with the combined HER2 blockade as we are with our combined HER2 blockade plus chemotherapy. I'm certain that there is a group of patients who can be treated with this targeted therapy alone. Now the question is, how can we identify them ahead of time and spare them the toxicities and costs of chemotherapy?
CancerNetwork: Not using chemotherapy—is this something that is going to be part of a session at the San Antonio meeting?
Dr. Osborne: Not much, but I'm going to mention it briefly in my discussion of three papers that will be presented at the meeting on HER2-targeted therapy. On Friday, there is a study looking at a new HER pathway inhibitor called neratinib, and then there is the CLEOPATRA study. There's also another study looking at the combination of Herceptin plus pertuzumab and at different chemotherapy regimens to determine how tolerable the regimens are. I'll be discussing that, and one of the questions I will raise is, do we really need chemotherapy in all patients or is there a subset who may not need it? But because those studies were presented at either ASCO or last year at this meeting, it's not going to be a major discussion point until additional data come out.
CancerNetwork: We know that it takes an understanding of both the biology and the pathways involved in breast cancer to effectively diagnose and treat the disease—and the SABCS puts an emphasis on allowing communication between clinicians and basic researchers. Could you describe how this came to be a critical aspect of the symposium?
Dr. Osborne: Yes. The story involves Bill McGuire and Charles Coltman, who are the co-directors of the division where I first started my career in 1977 at the University of Texas Health Science Center at San Antonio. The three of us started this symposium way back then, and initially it was just a symposium for the local cancer doctors, a sort of educational meeting, but then we decided that we should bring in some science and requested that people submit abstracts and asked them to present their research data at the meeting. It was Bill's philosophy back then, and I guess I inherited it when I began to take over the meeting as director in 1992—it was the idea of translational research, which is doing research in the laboratory that can be directly translated to improving patient care. Bill might have been one of the first translational researchers for any disease, before the term was even coined.
Bill always believed that the meeting should include basic science and clinical science, and that these two different types of research should all be presented in the same room, not in separate rooms, so that the clinicians would have a greater understanding of the biology of the disease and the basic scientists would have a greater understanding of the challenges in the clinic. I think that's been a very successful approach, and in fact, although there is an occasional clinician who says, “Gee, I'm bored by the basic science,” or a basic scientist who says, “Gee, the clinical stuff doesn't have any relevance to me,” the great majority of the people have liked this format. You sit in one room and you hear about biology and you hear about the results of clinical trials. I think that cross-fertilization has been very good. We were probably doing that earlier in many ways, but now it's mandatory because now our treatments are all based on knowing the biology of the disease and knowing what pathways are driving the cancer and what could be the escape pathways, when the tumor outsmarts us, to get around the drug that we're using. One has to know the biology of the disease now, so we're going to keep this format of having biology and clinical medicine presented at the meeting together.