Breast Cancer and Oncology: The Latest Developments
Issue: September 2009
By: Yelena Krijanovski, M.D.
Worldwide, breast cancer is the second most common form of cancer in women and the fifth leading cause of death (WHO data). In the U.S., it’s the seventh leading cause of death. The good news is that 88-90% of those diagnosed early will survive for 10 years or longer.
While metastatic breast cancer, which tends to spread to the bones, lungs or brain, cannot be cured, it can be controlled for some time. Twenty percent of patients withmetastasis will survive five years, and 10-15% will live at least 10 years. We also have the ability to control cancer with aggressive features that has not metastasized; while it may frequently recur, 56% of these patients will survive for 10 years.
Treating Older Patients
One of the biggest challenges for medical oncologists is treating older patients who have breast cancer. Although the age range for breast cancer can span between age 30 and 90, most breast cancer patients are at least 65 years old, and some biases exist with respect to how to treat them.
A patient who is very sick is not going to do well with chemotherapy, but over the last several years, some studies have shown that relatively healthy older people with reasonable organ function will do pretty well with standard chemotherapy. Older patients seem to have lower toxicities (such as nausea), less anxiety about treatment, and less psychosocial stress. Besides being a little more immune, their response to chemotherapy is the same for younger patients, with similar survival rates.
Historically, adjuvant chemotherapy recommendations were based on tumor characteristics such as age, comorbid conditions, tumor size, node status, hormone receptor status, and HER-2 status. The challenge remains as to what chemotherapy combination to use for good performance older women adjuvantly or neoadjuvantly if the cancer is locally advanced or large but operable. Recent study results have shown that the combination of docetaxel and cyclophosphomide had superior disease-free survival compared with standard doxorubicin plus cyclophosphomide, and older patients tolerate that regimen much better.
Recent Research
Research continues in this area, so more data on the effects of each approach are yet to come. The American Society of Clinical Oncology (ASCO) is one of many great sources to learn the results of cutting-edge scientific and educational developments in oncology. At the last meeting, in Orlando, information on two studies was brought to my attention:
·The combination of bevacizumab with taxanes is now being tested in an adjuvant setting after the Phase III study of patients with metastatic cancer revealed increased progression-free survival.
·The combination of transtuzumab and bevacizumab in a Phase II study resulted in an overall response rate more than 50%. Trials are currently ongoing to evaluate the combination of these two targeted agents in women with HER-2-positive breast cancer in an adjuvant setting.
Neoadjuvant Treatment
Challenges remain for patients who undergo neoadjuvant treatment and have residual disease. M.D. Anderson Cancer Center clinical trial analysis has shown that patients who reached complete pathologic response have markedly improved disease-free survival and overall survival relative to those with residual disease—even those patients with a hormone receptor-positive cancer. Data also suggest that there’s minimum benefit for additional chemotherapy in patients with residual disease post-surgically. It’s been concluded that new targets need to be identified in order to develop non cross-resistant agents for the treatment of patients with residual disease. It would be helpful to have genomic tools available as upfront predictive markers of response to better guide additional adjuvant therapy.
Data about neoadjuvant endocrine therapy were presented as an emerging option for hormone-sensitive locally advanced operable breast cancers. Trials show that aromatose inhibitors have a significantly higher objective response rate and rate of conversion to breast-conserving surgery then tamoxifen in appropriately selected postmenopausal patients. Usually treatment goes beyond four months and the characteristic histological feature for responders is central scar formation.
Optimal sequencing of hormonal therapy has been addressed again for hormone receptor-positive patients in an adjuvant setting. We still don’t have an answer regarding optimal use, timing and duration of treatment, and the best strategy for this particular subset of patients.
I was also made aware of important data about the role of breast MRI-guided local staging. Randomized trials show that pre-operative MRIs don’t reduce re-excision rates; the incremental detection rate of cancer was 4% and the detection of new cancer sites in the contralateral breast was reported at 9%, with low-to-moderate predictive value. However, it does change the recommended surgical treatment, with breast-conserving surgery frequently being abandoned in favor of more extensive surgery (wide excision or mastectomy) as the use of an MRI frequently upgrades disease to multi-focal and/or multi-centric. We do realize that MRI is associated with false positive detection; in one trial, the ratio of true to false was 1.9:1.
Those of us in the oncology field will continue to monitor the latest developments in medical oncology, radiation and surgical approaches, as well as reconstructive surgery, so we’re able to offer patients the most cutting-edge treatment that’s relevant to their specific cancer. We’re delighted to see the survival rate of breast cancer patients continue to grow, and our goal is to watch this rate steadily climb.
Yelena Krijanovski, M.D. is medical oncologist affiliated with Sutter Regional Medical Foundation and Sutter Solano Medical Center.
