Proton therapy may treat
breast cancer more effectively than radiation.
Proton therapy an option for breast cancer patients
February 07, 2013
by Carol Ko
, Staff Writer
Proton beam therapy may offer breast cancer patients the benefits of radiation without some of its serious side effects, which include heart disease.
Radiation oncologists from cancer centers around the country will meet in Phoenix on Friday to discuss the use of proton beam therapy to treat breast cancer.
Scientists have long known that breast cancer patients who receive radiation therapy face higher risk for heart attacks and other heart-related problems 15 to 30 years down the line. The risk is particularly pronounced for women who receive radiation treatment for their left breast because it's located right above the heart. Since proton therapy precisely targets cancer cells without damaging healthy tissue, it may be a more effective treatment option for select breast cancer patients.
An estimated 230,000 women are diagnosed with breast cancer in the U.S. every year. Experts estimate that just under half of those women receive radiation therapy — typically newly diagnosed patients who have a localized lesion in the breast. After undergoing a lumpectomy, the patient receives radiation targeted at the remainder of the breast tissue or the area where the tumor used to be to eliminate all traces of the cancer.
A startling number of older women with high-risk advanced breast cancer — nearly half — forgo recommended radiation therapy after their mastectomy, a 2011 study shows. Though doctors still don't know the reason behind this trend, the consequences are serious: the cancer will return for 30 to 40 percent of those women.
In the bigger picture, breast cancer patients who receive radiation therapy fare much better on average than patients who forgo radiation because they have lower rates of cancer recurrence. However, they also face a higher risk of secondary complications.
One Norway study that examined coronary disease among breast cancer patients found that patients who received radiation therapy in the left breast had a much higher chance of having constricted blood vessels in the front of the heart, where radiation exposure would have been more likely. These patients are consequently at much higher risk for heart attacks and/or heart muscle damage.
Radiation oncologists treat breast cancer by aiming the beam at an angle across the chest, inadvertently exposing parts of the lung and heart to radiation. Proton therapy largely sidesteps this problem because it offers depth control: "It goes in a certain distance and stops — so we can treat the chest wall as the patient receives less radiation dose and we can also avoid the heart and the lungs," Dr. William Hartsell, medical director of the CDH Proton Center, A ProCure Center, told DOTmed News.
So who would be an ideal candidate for this new treatment? "Women who would benefit most would be women with larger tumors, or who have tumors in multiple lymph nodes — especially if this is a left-sided breast cancer," said Hartsell, who explains that it's particularly difficult to treat more widespread areas on the left side thoroughly while missing the heart.
Researchers attending the conference on Friday will discuss issues around treatment techniques, patient selection and the challenges of measuring the treatment's long-term efficacy in relation to radiation therapy. "The problem is, we're trying to prevent something that's going to happen 15, 20 years down the line," said Hartsell. "We can't run a test immediately afterward that says, yes, we're effective in preventing that problem." He also notes that a series of clinical trials in proton centers assessing long-term outcomes are currently underway.
Though many experts agree that the technology holds promise, it comes with a hefty price tag: proton therapy treatment costs around $50,000, or twice as much as standard radiation. Building a proton center also requires a very large capital investment up front -- roughly $100 to $200 million. To add fuel to the fire, Medicare is offering generous reimbursements for the procedure, paying around $50,000 for patients undergoing prostate cancer treatment.
Skeptics criticize what they see as a hasty medical arms race to adopt a new technology whose benefits have yet to be established in long-term studies. Mayo Clinic, for example, plans to build two proton centers in Minnesota and Arizona to compete with other hospitals such as the University of Pennsylvania and Loma Linda.
However, Hartsell points out that just looking at the price tag is misleading. "Proton centers treat a lot more patients per center than an X-ray center," he said. "You're talking about putting in a Wal-Mart versus a 7-Eleven. The Wal-Mart serves a lot more customers, so there's a lot more cost that goes into the building of it." He also points out that the initial cost savings of using standard radiation therapy may be lost quickly if those patients are later at increased risk for radiation-related heart attacks or lung tissue damage.
"For women with high-risk breast cancer, it makes a lot of sense to evaluate the use of protons to make a big difference in those women's lives 15, 20 years down the line," said Hartsell.