Breast Cancer Radiation Therapy Works in Fewer But Higher Doses
The regimen is less challenging for patients but equally effective in preventing relapse, British studies find
TUESDAY, March 18, 2008 (HealthDay News) -- The use of radiation therapy in fewer, but higher doses appears to be just as effective as conventional doses for women recovering from breast cancer, British researchers report.
Because fewer treatments are needed, the overall amount of radiation the patient receives is actually less, though treatment outcomes remain the same or better, according to two British trials appearing this week in the April edition of the journal Lancet Oncology and an upcoming edition of The Lancet.
The studies, led by researchers at the Institute of Cancer Research, in Sutton, support what other trials have already shown and what doctors have noted in practice settings, experts said.
"These two studies confirm work done in the U.S.," said Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge, LA. "Today, there are a whole bunch of techniques to give shorter courses of radiation."
According to background information in the studies, the international standard radiation schedule for breast cancer treatment involves a high total dose delivered in 25 small daily doses or fractions. But this approach, which reduces the risk of local cancer relapse by about 70 percent, requires a huge investment of time and effort on the part of the patient.
"One of the biggest problems in radiation therapy is just the sheer amount of time it takes for women to receive treatment," Brooks said. "In the U.S., traditionally, it's about six weeks of treatment. When many women live 50 miles from a radiation center, that's a 100-mile trip each day, five days a week. That's an enormous amount of time and effort to have radiation."
In the first trial, known as START A, 2,236 women with early-stage breast cancer were randomly assigned to receive the conventional dose of radiotherapy or one of two regimens both involving fewer but larger fractions of radiation.
All treatments were given over five weeks, essentially the standard amount of time for conventional radiotherapy.
After a median follow-up of about five years, the rate of tumor recurrence was about equivalent in the two groups. There also seemed to be fewer adverse effects in the groups receiving the lower total dosage.
The second trial, known as START B, involved 2,215 women, again with early breast cancer, who were randomly assigned after surgery to receive the conventional, higher dose of radiation or to receive fewer, larger fractions. The conventional arm received their therapy over five weeks while the second group received theirs over three weeks.
This time, after a median follow-up of six years, the rate of tumor recurrence was 2.2 percent in the group receiving a smaller total dose of radiation, versus 3.3 percent in the conventional-treatment arm.
For more on breast cancer treatment, visit the U.S. National Cancer Institute.