A judgment call
Sometimes it can take years for doctors to determine the best way to use promising new treatments. But while clinical testing is under way, how can doctors determine whether novel treatments are right for individual patients?
Complex mathematical models enable Rinaa Punglia, MD, MPH, to spot trends in research studies that can guide patients to the therapy best suited to their needs.
In the Women's Cancers Program at Dana-Farber, Rinaa Punglia, MD, MPH, a radiation oncologist, is using complex mathematical models to pick out trends in clinical trials while they are in progress. Like a pre-election opinion poll, her work makes it possible to glimpse outcomes in advance, giving doctors information that can help patients right away.
An example is a study comparing two treatments—the drug tamoxifen and a newer class of substances called aromatase inhibitors—for preventing breast cancer recurrence in postmenopausal women with an early stage of the disease. Dr. Punglia and DFCI colleague Harold Burstein, MD, PhD, are using computer models to predict how future clinical trials of the two therapies will turn out.
"The challenge is to devise a plausible way of modeling outcomes," Dr. Punglia states. "We need to decide which data to include, and find ways of capturing and categorizing it so that it gives an accurate forecast of the trial's eventual results."
Another project aims to help some patients weigh the benefits and drawbacks of radiation therapy plus tamoxifen versus tamoxifen alone for certain women with breast cancer. Combining radiation therapy with tamoxifen is known to reduce the chances that cancer will recur in the original location. But it also requires patients to receive radiation treatment every day for six weeks, a costly, inconvenient prospect for many that can also produce mild changes in the breast's appearance.
In a study using mathematical models, Dr. Punglia and her colleagues compared radiation and tamoxifen therapy versus tamoxifen alone in postmenopausal women with small breast tumors fueled by estrogen. Drawing on data in published reports and clinical trials, the investigators estimated patients' overall survival rate, the recurrence-free survival rate, and the likelihood of death due to breast cancer. They tabulated results based on the women's ages.
Among their findings: Over their lifespan, 50-year-old women had a 2.4 percent chance of dying from breast cancer if treated with radiation and tamoxifen, compared with a 5.3 percent chance if taking tamoxifen alone. By contrast, 80-year-olds had a 1.2 percent chance of dying of breast cancer if they received the combined therapy, versus 2 percent with tamoxifen alone.
"Our findings can help patients choose the course of therapy that makes the most sense for them," Dr. Punglia remarks. "Knowing the risks and benefits of various procedures makes it possible for physicians to tailor treatments to their patients' preferences."
