By Kathleen Doheny
MONDAY, June 3 (HealthDay News) — Two common schedules used for the chemotherapy paclitaxel (Taxol) are equally effective at controlling breast cancer, but fewer side effects are found with the weekly regimen rather than every two weeks, according to a new study.
The estimated five-year progression-free survival rates were the same for both groups, said Dr. G. Thomas Budd, who led the study. While 82 percent of the group treated weekly had progression-free survival five years later, 81 percent of the every two weeks group did.
However, “for the weekly group, overall the side effects seem fewer, particularly the aches and pains,” said Budd, a professor of medicine at the Cleveland Clinic Lerner College of Medicine of Case Western University, in Ohio.
He is due to present his findings Monday at the annual meeting of the American Society of Clinical Oncology, in Chicago.
In another study, also to be presented Monday, Dr. Emiel Rutgers, a surgical oncologist at the Netherlands Cancer Institute, in Amsterdam, looked at the side effect of lymphedema — a painful swelling of the arm, breast and chest that can occur after breast cancer treatment.
Lymphedema was about half as frequent in women with positive axillary (armpit) lymph nodes who received radiation therapy in the area than in women who had surgical removal of the nodes.
Both studies focus on the “fine-tuning” of breast cancer treatments to maintain the benefits and reduce treatment side effects.
According to Budd, doctors now typically are divided on the regimen of Taxol, with some giving it weekly and others every two weeks. “And we haven’t known the best way to do it,” he said.
In the study, he compared the two treatment schedules in more than 2,700 breast cancer patients between 2003 and 2010. One group got a standard dose of Taxol every two weeks for 12 weeks; the other got low-dose Taxol weekly.
After finding no differences in survival rates, he looked at side effects. Women on the two-week schedule had more allergic reactions (1.4 percent of patients compared with 0.6 percent), more muscle and bone pain (11 percent compared with 3 percent) and more numbness and tingling in the extremities (17 percent versus 10 percent).
In practice, he said, most doctors who give the two-week regimen give four cycles (rather than six cycles). He gave the same number of cycles to each group to make the comparison more equal. So, the “real-life” differences in some side effects, he said, may be smaller.
Many doctors are already using the weekly chemotherapy schedule, according to Dr. Joanne Mortimer, director of women’s cancer programs and co-director of the breast cancer program at the City of Hope Cancer Center, in Duarte, Calif. She reviewed the new findings. “It could be practice-changing,” she said, for doctors not giving it weekly.
In the lymphedema study, Rutgers compared 744 breast cancer patients with positive lymph nodes who had surgery to remove them to 681 patients who received radiation to the area.
When the sentinel node — the first draining node of a breast tumor — is found to have cancer cells, treatment is needed. The standard is to remove all the nodes in the armpit area, but radiation is an alternative.
A potential side effect of treatment, however, is lymphedema.
Rutgers followed the patients for five years. “After five years, patients who had positive nodes and were treated with radiation had half the lymphedema-associated problems as those treated with surgery,” he said.
In addition, at five years, 14 percent of the radiation group developed lymphedema, but 28 percent of the surgery group reported it, the investigators found.
However, Rutgers found no substantial differences between the groups when he looked at overall survival or cancer-free survival.
For her part, Mortimer noted that the radiation treatment studied by Rutgers is more commonly done in Europe. But the option is definitely being considered more in the United States, as well, she said.
Women told they need treatment for affected lymph nodes, she said, “should ask their doctor if radiation is a feasible option.”
Because both studies were presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.
To learn more about lymphedema, visit the American Cancer Society.