STANFORD, CA—With growing concern about overtreatment of breast cancer as outcomes have improved over time, not much research has been performed on how chemotherapy use and oncologists’ recommendations have changed in recent years.

A new study published online by the Journal of the National Cancer Institute sought to fill that gap.1

A study team led by Stanford University researchers and also including participation from the VA’s Center for Clinical Management Research surveyed 5,080 women identified through two surveillance, epidemiology and end results registries from the state of Georgia and the city of Los Angeles. Participants, who responded at a 70% rate, all had been diagnosed with breast cancer between 2013 and 2015.

The patients were asked about the chemotherapy they received, as well as their oncologist’s recommendations. At the same time, researchers surveyed 504 attending oncologists (60.3% response rate) about chemotherapy recommendations in node-negative and node-positive case scenarios. The analytic sample was 2,926 patients with stage I-II, estrogen receptor-positive, human epidermal growth factor receptor 2-negative breast cancer.

Results indicated that, from 2013 to 2015, other factors kept constant, chemotherapy use was estimated to decline from 34.5% (95% confidence interval [CI] = 30.8% to 38.3%) to 21.3% (95% CI = 19.0% to 23.7%, P < .001). Estimated decline in chemotherapy use was from 26.6% (95% CI = 23.0% to 30.7%) to 14.1% (95% CI = 12.0% to 16.3%) for node-negative/micrometastasis patients, and from 81.1% (95% CI = 76.6% to 85.0%) to 64.2% (95% CI = 58.6% to 69.6%) for node-positive patients.

Study authors reported that use of the 21-gene recurrence score (RS) did not change among node-negative/micrometastasis patients, and increasing RS use in node-positive patients accounted for one-third of the chemotherapy decline.

In addition, patients’ report of oncologists’ recommendations for chemotherapy declined from 44.9% (95% CI = 40.2% to 49.7%) to 31.6% (95% CI = 25.9% to 37.9%), controlling for other factors. The study found that oncologists were much more likely to order RS if patient preferences were discordant with their recommendations (67.4%, 95% CI = 61.7% to 73.0%, vs 17.5%, 95% CI = 13.1% to 22.0%, concordant), and they adjusted recommendations based on patient preferences and RS results.

“For both node-negative/micrometastasis and node-positive patients, chemotherapy receipt and oncologists’ recommendations for chemotherapy declined markedly over time, without substantial change in practice guidelines,” study authors concluded. “Results of ongoing trials will be essential to confirm the quality of this approach to breast cancer care.”

  1. Kurian AW, Bondarenko I, Jagsi R, Friese CR, McLeod MC, Hawley ST, Hamilton AS, Ward KC, Hofer TP, Katz SJ. Recent Trends in Chemotherapy Use and Oncologists’ Treatment Recommendations for Early-Stage Breast Cancer. J Natl Cancer Inst. 2017 Dec 11. doi: 10.1093/jnci/djx239. [Epub ahead of print] PubMed PMID: 29237009.