Patients with metastatic breast cancer who respond to chemotherapy are unlikely to see any additional benefits from surgery or radiation therapy, according to leaders of a new clinical trial.
The randomized, controlled study, which was presented Wednesday at the San Antonio Breast Cancer Symposium, was intended to settle a long-running dispute among oncologists about the best way to treat women whose tumors had spread to other parts of their bodies, said Dr. Rajendra Badwe, director of the Tata Memorial Hospital in Mumbai, India.
"For a surgeon like myself, knowing when to do surgery is important," said Badwe, who led the trial. "But even more important is knowing when not to do it."
The message may come as welcome news to some breast cancer patients, who now have medical evidence on their side if they opt to take a pass on painful, invasive procedures that aren't likely to extend their lives. But for other women with metastatic disease, the message that there's not much they can do beyond chemotherapy is sure to be unsettling, patient advocates said.
"It can be very disheartening for a woman diagnosed with Stage IV breast cancer to learn that surgery is not recommended for her," said Musa Mayer, a breast cancer survivor who operates the website AdvancedBC.org. "She may see this as a message of futility."
In the United States, Canada and Europe, roughly 5% to 10% of all breast cancer patients are diagnosed after their tumors have already spread. In the developing world, where access to medical care isn't as good, 10% to 20% of patients have metastatic disease by the time they're diagnosed.
Researchers conducting experiments in animals and studying the clinical records of human patients have sometimes observed an association between the surgical removal of primary cancer tumors and the rapid growth of secondary tumors in other areas of the body.
The cause of this phenomenon, which does not occur in all cases, remains unclear. Oncologists have offered several possible explanations, including the hypothesis that as the body recovers from surgery, it releases growth factors that accelerate the development of new tumors. Others speculate that the primary tumor itself may somehow inhibit the growth of distant metastases, and that this influence is lost when the tumor is removed.
Cancer specialists are split over how to deal with this potential problem. If chemotherapy is already working, some doctors recommend against further treatment with surgery or radiation unless there is bleeding or ulceration, a sign that a tumor is causing serious problems and needs to be removed immediately. Other doctors say the risk of accelerating new tumor growth is only theoretical, and that surgery increases patient survival.
"We've had a house divided," Badwe said. "Some say surgery is inappropriate, while others say it saves lives."
So Badwe and his colleagues set out to examine whether surgery and radiation actually did extend a patient's survival. They enrolled 350 Indian women who were diagnosed with metastatic breast cancer and who also showed a positive response to chemotherapy.
Among the volunteers, 177 continued treatment with chemotherapy only and 173 had partial or complete removal of their breast and removal of nearby lymph nodes, followed by radiotherapy.
Seventeen months later, 218 of the patients had died -- 107 from the chemotherapy-only group and 111 from the surgery and radiation group. Overall survival after two years of follow-up was 43% among the chemotherapy patients and 40% for the patients who had more aggressive treatment.
Statistically speaking, the outcomes for both groups were the same, the authors concluded. "We found there was no difference in overall survival," Badwe said.
Dr. Courtney Vito, a surgical oncologist at the City of Hope cancer center in Duarte who wasn't involved in the study, said the findings were significant, especially in light of advances in drug treatments.
"We've actually been able to see drugs completely resolve small distant metastases and all that's left is in the breast," she said. "Well, what do you do with those women?"
Vito agreed with Badwe that oncologists were split into two camps when it came to the issue of surgical removal of primary tumors, but that she did not think the new study would end the long-running debate.
"This study reinforces my own personal bias" to leave the primary tumor alone, Vito said. "But for people in the camp that think stage IV mastectomy is valuable, this probably will not be enough" to convince them to skip surgery.
Efforts to conduct similar studies in the United States have encountered serious problems enrolling patients, she said.
"Women who believe that removing their breast will help them don't want to be randomized and let the trial decide if they get surgery or not," Vito said. "It's the same for patients that don't want to get surgery. ... Some people say a study like this would never be able to be done and it looks like these authors have done it and come up with an answer."
Mayer, the breast cancer survivor, said the trial appeared to be the first high-quality evidence to address the issue, although she wondered just how women would respond to news that surgery wouldn't help them.
"For many women, a simple lumpectomy or mastectomy offers the satisfaction that the cancer in her breast is gone," she said. "This is not a small thing, even for a woman who realizes that there are metastatic sites of cancer elsewhere in her body."