(RxWiki News) As doctors become better and better at detecting breast cancer early, some question whether every early detection warrants early surgery. New evidence suggests that the answer to that question may depend on the type of breast cancer patients have.
A new study found that while surgery to treat an early type of breast cancer appeared to help patients with faster-growing types of the disease live longer, it did not seem to help patients with a slower-growing form of the cancer.
"Because the prevalence of breast cancer screening has increased, early detection has contributed to a dramatic increase in the incidence of [ductal carcinoma in situ]," explained the authors of this study, led by Yasuaki Sagara, MD, of the Dana-Farber/Brigham and Women’s Cancer Center in Boston.
Ductal carcinoma in situ (DCIS) is breast cancer that develops in the milk ducts. DCIS is an early and noninvasive form of the disease, meaning the cancer hasn't yet spread to other parts of the breast or body.
Dr. Sagara and team used data from the Surveillance, Epidemiology, and End Results (SEER) database for the years 1988 through 2011 to identify 57,222 cases of DCIS across the US.
These researchers compared the outcomes of the 1,169 patients (2 percent) who did not receive surgery to the remaining 98 percent who did. These patients were followed for a median of six years, during which 576 died due to breast cancer.
Overall, Dr. Sagara and team determined that 93.4 percent of the nonsurgery group and 98.5 percent of the surgery group were still alive 10 years after being diagnosed with DCIS. However, they noticed different results when they considered the grade, or severity, of the cancer.
"Doctors classify DCIS into high grade (more quickly growing) and low grade (more slowly growing)," according to Cancer Research UK. "Doctors think that the high grade DCIS is more likely to spread into the surrounding breast tissue and more likely to come back after treatment."
Among women diagnosed with low-grade DCIS, 98.8 percent of the nonsurgery group and 98.6 percent of the surgery group were alive after 10 years — almost identical results.
According to Dr. Sagara and team, these results suggest that surgery was more beneficial among women with high-grade DCIS. Among these women, 90.5 percent of the nonsurgery group and 98.4 percent of the surgery group were still alive after 10 years.
"This study alone does not allow us to definitively conclude that breast surgery should be avoided for women with low-grade DCIS, but we believe that a prospective clinical trial — following patients over time from diagnosis through treatment and beyond — is warranted," Dr. Sagara said in a news release.
In an editorial about this study, Julie A. Margenthaler, MD, of the Washington University School of Medicine in St. Louis, and Aislinn Vaughan, MD, of SSM Breast Care in St. Charles, MO, preached caution when it comes to considering these results.
For one, Drs. Margenthaler and Vaughan noted that 14 percent of the nonsurgery group in this study received radiation therapy, which is not a treatment traditionally used for DCIS. They also explained that much is still being learned about which cases of DCIS will progress.
"Our current inability to accurately predict which women with DCIS are at the greatest risk for developing invasive disease generally necessitates that all patients diagnosed as having DCIS undergo treatment," Drs. Margenthaler and Vaughan wrote.
They added, "For now, surgeons should hold onto their scalpels."
The study and editorial were published online June 3 in JAMA Surgery. Dr. Sagara and team disclosed no funding sources or conflicts of interest.