Between 2013 and 2015, the percentage of women with early stage breast cancer who received chemotherapy dropped sharply, despite any change in treatment guidelines or new evidence. A new study led by researchers at Stanford University and the University of Michigan documented the change and explored the factors that may be contributing to lower rates of chemotherapy in this population.
The study, published in the Journal of the National Cancer Institute, revealed that chemotherapy use declined from 34.5% to 21.3% in those two years. Among women with node-negative or micrometastatic cancer, the rate plummeted from 26.6% to 14.1%, while for those with node-positive breast cancer, the rate dropped from 81.1% to 64.2%. Patients also reported a significant decline in recommendations for chemotherapy by their oncologists, from 44.9% in 2013 to 31.6% in 2015.
Chemotherapy. (Source: Pixabay)
“For patients with early stage breast cancer, we’ve seen a significant decline in chemotherapy use over the last few years without a real change in evidence,” said lead author Allison Kurian, MD. “This likely reflects a change in the culture of how physicians are practicing, and a move toward using tumor biology to guide treatment choices rather than solely relying on clinical measures.”
The team surveyed 5080 women who received treatment for early breast cancer who were identified through the Surveillance, Epidemiology, and End Results (SEER) registries in Georgia or Los Angeles. The survey asked patients whether they received chemotherapy and what their oncologists had recommended for their treatment. For the analysis, the researchers used data from 2926 patients who had stage I or II, estrogen receptor-positive, human epidermal growth factor receptor 2 negative (EGFR2-) breast cancer.
In addition, the team surveyed 504 oncologists, of whom 304 responded, about their chemotherapy recommendations in hypothetical cases with with node-negative or node-positive patients.
The oncologists reported that they were more likely to order genomic testing of tumors if a node-positive patient pushed back about receiving chemotherapy, with 67.4% saying they would use the testing to estimate the risk of recurrence. Genomic testing was much less likely when the oncologist and patient agreed on next steps for treatment, with just 17.5% requesting tumor analysis in that instance. Rates of testing in patients with node-negative cancer remained the same over the study period.
The authors linked the results to efforts by medical oncologists to “reduce the burden of treatment for patients diagnosed with curable breast cancer” and the availability of tests that more accurately predict the benefits of adjuvant chemotherapy for specific patients.
“The decline in chemotherapy use despite an incomplete evidence base suggests a broad change in culture, with oncologists moving away from chemotherapy for patients with hormone-responsive early breast cancer” as a result of a shift toward personalized therapy based on tumor biology and concerns about toxicity in instances where chemotherapy may not provide significant benefit, the authors concluded.