Recent clinical trials have shown that 90 percent of early stage breast cancer patients over age 70 do not benefit from radiation after breast-conserving surgery. And yet, use of radiation in this context has dropped only minimally.
A new University of Michigan study examines why.
"In the last 30 to 40 years, we've learned the value of doing less," says study author Dean Shumway, M.D., assistant professor of radiation oncology at Michigan Medicine. "In breast cancer, we've gone from radical mastectomy with removal of the breast and pectoralis muscle, to a modified radical mastectomy with removal of the breast, to breast conservation and radiation without negatively affecting outcomes."
Researchers, he says, have begun to identify whether patients who undergo lumpectomy can avoid radiation without compromising outcomes.
Two recent prospective clinical trials observed a favorable outcome among older women with stage 1, estrogen receptor-positive breast cancer, even with omission of radiotherapy.
"These studies showed that whether or not older women with small tumors receive radiation, they live the same amount of time," says Shumway. "Radiation does not appear to prolong survival. Even though it does significantly decrease the chance of the tumor coming back, after 10 years it was only a 10 percent recurrence rate without radiation. With radiation, it would reduce the recurrence rate to about 2 percent."
Put another way, he notes, 90 percent of these patients would not benefit from radiation and would do well with a lumpectomy alone, as long as they are compliant with endocrine therapy for five years.
Have these findings changed the way physicians treat this subset of patients?
"There was some change, mainly in the oldest and sickest patients, but 60 percent of patients older than age 80 still receive radiation," says Shumway. "My goal with this study was to investigate how physicians view the option of omitting radiotherapy, with the goal of understanding more about why practice patterns haven't changed.
"Until now, no one had asked them."
Split opinions in practice, perception
U-M researchers mailed a survey to 879 surgeons and 713 radiation oncologists who regularly treat breast cancer. The survey questions evaluated physician attitudes, knowledge, communication and recommendations regarding the omission of radiation therapy in older women with early stage breast cancer.
In his large national sample, published in the Annals of Surgical Oncology, researchers found that 40 percent of surgeons and 20 percent of radiation oncologists were uncomfortable with omitting radiation after lumpectomy.
A sizable minority in both specialties erroneously associated radiotherapy in this scenario with improvement in survival for early stage patients. They also overestimated the risk of local recurrence if radiation is omitted.
Additionally, clinicians who overestimated the benefits of radiotherapy were more likely to consider radiotherapy omission to be an unreasonable option.
To better assess attitudes, the survey proposed specific patient scenarios. In one scenario, physicians were asked if they would recommend radiation to an unhealthy 81-year-old woman who was a borderline surgical candidate.
One-third said they would -; a margin that surprised the research team.
"The finding that we didn't expect was that surgeons are generally more uncomfortable with the idea of omitting radiation than radiation oncologists are," says Shumway. "It's viewed as a departure from the standard of care."
The pressure of patient expectations
A majority of surveyed physicians reported that patients want the most aggressive treatment, even if the benefit is small, and that it takes more effort to tell patients that they do not need radiation than it does to recommend it.
"It's important to recognize that this is a controversial area," says Shumway. "You can't say that offering radiation to older women is wrong. It really is a patient-driven decision, and it depends on the patient's own values and preferences, in addition to her risk of recurrence and overall health."
As the point of first contact for breast cancer patients, surgeons have a tremendous influence on how patients choose treatment options.
Which is why Shumway thinks they could play a crucial role in counseling older women about options for less aggressive therapy.
"The population is aging, and this is going to be an issue that affects more women," says Shumway. "There is increasing attention given to considerations that are unique to older patients -; and in this case, their vulnerability for overtreatment."
Shumway's future work will focus on developing interventions to help patients make fully informed decisions and understand the concept of competing causes of mortality.
"We're searching for innovative ways of helping patients make fully informed, high-quality decisions that are consistent with their own values and preferences," says Shumway. "Our study provides a detailed view into the physician perspective on how the decision is made to omit radiotherapy. We hope this insight will be useful in improving delivery of individualized care for older women with early stage breast cancer."