SNLB, Radiotherapy Do Not Improve Outcomes in Older Patients With Breast Cancer

New data suggest 2 procedures for patients with breast cancer remain common in older patients, even though they do not appear to have a significant impact on outcomes in these patients.¹

The report, published in JAMA Network Open, underscores the difficult choices patients and their doctors face when deciding which interventions, if any, to undertake. It also suggests patients and physicians are choosing to undertake interventions more often than is clinically meaningful.

Senior author Priscilla F. McAuliffe, MD, PhD, of UPMC Hillman Cancer Center, and colleagues, explained that few guidelines exist for treating older patients with breast cancer, largely because such patients are under-represented in clinical trials.

In 2016, the Society of Surgical Oncology adopted new “Choosing Wisely” recommendations, which advised against the routine use of sentinel lymph node biopsy (SLNB) for axillary staging in older patients. Similarly, the National Comprehensive Cancer Network has suggested that de-implementation of radiotherapy (RT) in older patients may be possible.

In this study, the investigators sought to figure out the extent to which SLNB and RT were still being performed in older patients. Additionally, they wanted to understand whether and how much such procedures impacted patient outcomes.

The investigators used data from more than 3361 women who were over the age of 70 years at the time of diagnosis, had cancers that were estrogen receptor–positive and HER2-negative, and had clinically node-negative breast cancer. The data covered the period from 2010 to 2018, and all of the patients were treated at 1 of 15 community and academic hospitals within the UPMC network.

The data showed that both SLNB and RT were quite common. Nearly two-thirds (65.3%) of patients underwent SLNB, and more than half (54.4%) received adjuvant RT. In the case of SLNB, usage rates went up over the period of the study, increasing by 1% per year. Rates of RT declined over the 8-year time frame, by an average of 3.4% per year.

Yet, when the investigators examined the outcomes of patients who did and did not receive the procedures, they found no evidence that the procedures made a difference.

For this portion of the study, the data were limited to patients receiving care between 2010 and 2014, which enabled the investigators to use a median follow-up of 4.1 years. Among the 2109 patients in the outcome analysis, no association was found between SLNB and locoregional recurrence-free survival (LRFS; HR, 1.26; 95% CI, 0.37-4.30; P =.71), nor was SLNB associated with disease-free survival (DFS; HR, 1.92; 95% 0.86-4.32; P =.11).

Similarly, RT did not lead to better LRFS (HR, 0.33; 95% CI, 0.09-1.24; P =.10) or DFS (HR, 0.99; 95% CI, 0.46-2.10; P =.97). Even when broken up by tumor grade or comorbidity, the investigators found no significant benefit to the procedures.

“This study is an example of how we can use big data to deliver on the promise of precision medicine–getting the right treatment to the right patient at the right time,” Hillman Cancer Center’s Adrian Lee, PhD, a co-author of the study, said in a press release.2 “Sometimes–as it happens to be in this case–that could mean deciding not to provide a certain treatment to ensure better care for the patient.”

The investigators said one problem when analyzing data about the effectiveness of procedures like SLNB is that patients who are healthier tend to be more likely to be offered the intervention, and also tend to be monitored more closely. Those patients may have better outcomes, but it is unclear if those improved outcomes are due to the intervention or due to their overall better health. To get around this problem, McAuliffe and colleagues conducted propensity score matching to get well-matched cohorts. This matching affirmed that SLNB did not improve LRFS or DFS.

McAuliffe said the data make clear that doing what’s best for patients often means making the difficult decision to forego certain interventions.

“As a breast surgeon, I want to give my patients the best chance of survival with the best quality of life,” she said, in the press release. “However, we have found that overtreatment of early-stage breast cancer in older patients may actually cause harm while not improving recurrent or survival rates.”

References

Carleton N, Zou J, Fang Y, et al. Outcomes after sentinel lymph node biopsy and radiotherapy in older women with early-stage, estrogen receptor-positive breast cancer. JAMA Netw Open. 2021;4(4):e216322. doi:10.1001/jamanetworkopen.2021.6322

2. Breast cancer treatment if those over 70 can be reduced. News release. UPMC Hillman Cancer Center. April 15, 2021. Accessed April 30, 2021. https://upmc.me/3u6Zgw1