A pair of studies suggest some patients with early-stage breast cancer may be able to safely avoid certain surgeries, adding to ongoing conversations about how aggressively to treat low-risk cancers.
The research was presented Dec. 12 at the San Antonio Breast Cancer Symposium.
One study involving 950 patients found women with ductal carcinoma in situ who were closely monitored were no more likely to develop invasive breast cancer than those who underwent surgery. Participants were randomly divided into two groups: one received the current standard of care — surgery with or without radiation — while the other followed active surveillance, which involved mammograms every six months.
Those in the active monitoring group could opt for surgery at any time, and most women in both cohorts received hormone therapy to prevent cancer growth. After two years, rates of invasive cancer were similar in both groups: about 6% in the surgery group and 4% in the monitoring group, according to the findings published in JAMA.
DCIS occurs when cells lining the milk ducts become abnormal while the surrounding breast tissue remains healthy. Often called "stage-zero" breast cancer, DCIS does not always progress to more advanced or invasive cancer. About 50,000 women in the U.S. are diagnosed with DCIS annually.
"Many women wonder — 'Do I really need to do this to myself?' - when they're faced with surgery and possibly radiation to remove DCIS," Shelley Hwang, MD, an author on the study and a breast cancer surgeon at Duke Cancer Institute, said in a news release. "These early results from our study give us reassurance that active monitoring is safe in the short term and that the cancers that are diagnosed during active monitoring are detected at an early stage."
Some physicians who were not involved in the research cautioned that the study period was too short to draw firm conclusions, The Wall Street Journal reported. Researchers acknowledged longer-term follow up is needed, and plan to conduct additional analyses after five, seven and 10 years.
A separate study published in The New England Journal of Medicine found women with early-stage breast cancer scheduled for breast-conserving surgery and who opted not to have their lymph nodes removed had similar outcomes to patients who did undergo lymph node removal surgery. Five years later, 92% of patients in both groups were still alive and cancer free. Women having breast cancer surgery often have a sentinel lymph node biopsy where lymph nodes in the armpit are removed to check if cancer is spreading, though the removal can cause chronic pain and arm swelling.
The findings add to conversations in the oncology community about whether certain low-risk cancers are overtreated. For example, physicians typically recommend careful monitoring for low-risk prostate cancers, which account for around one-quarter of men diagnosed with prostate cancer. Evidence has demonstrated this is an effective way to manage low-grade prostate cancer, while sparing patients from treatment side effects and cost. However, around 40% of patients with a lower-grade diagnosis opt for more aggressive treatment options, prompting debates about whether the lowest-risk cancers should be classified as cancer at all.