SEATTLE – A short course of neoadjuvant therapy could be considered in breast cancer patients with expected delays to resection, while they are awaiting surgery, according to study findings presented at the annual Society of Surgical Oncology Cancer Symposium.
More than half of breast cancer patients who undergo surgical resection as the initial modality will experience delays to surgery of more than 4 weeks. Of this group, more than half of patients receive shorter than standard courses of neoadjuvant therapy (NET), and the patients most likely to benefit were those older than 50 years, with ductal tumors, and the effect was seen in all T stages.
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chemotherapy
Recent reports show that NET is increasing. However, Dr. De Andrade pointed out, delays in receiving surgery remain a problem in breast cancer treatment and are associated with worse overall and cancer specific survival.
“Off-label use of NET is sometimes used in patients undergoing surgical delays,” he said.
NET use for 3 months has been associated with decreasing the size of tumors in patients with hormone receptor–positive (HR+) invasive breast cancer and allowing for breast conservation therapy. While short-term NET is sometimes used in women who are experiencing delay to surgery, the incidence and efficacy of this regimen remains undefined.
In the current study, Dr. De Andrade and his colleagues sought to answer three clinical questions:
• How long are patients with operable breast cancer waiting to undergo surgery?
• What is the pattern of use of short-course NET?
• What are the effects of short-course NET on outcomes?
The investigators used the National Cancer Database (NCDB) to identify women who had undergone surgery for stage 1-3 HR+ invasive breast cancer from 2004 to 2013. A total of 530,009 patients met inclusion criteria.
The primary outcomes of the study were time to surgery, the duration of NET, and if the pathologic stage at surgery was lower than clinical stage.
Among patients who did not receive NET, 49.3% underwent surgery within 30 days of diagnosis. More than a third (37.2%) underwent surgery within 60 days of diagnosis, and 13.5% did not have surgery until more than 60 days after their initial diagnosis. A total of 1.8% (9,664) patients underwent NET.
When looking at NET duration, 48% underwent NET for 12 or more weeks, while 52% received NET for less than 12 weeks; 27% received NET for less than 4 weeks, 17% for 4-8 weeks, and 9% for 8-12 weeks.
Downstaging from clinical stage to final pathology stage increased with longer duration of NET. It was 5.5% for less than 1 month on therapy, 9.7% for 1-2 months, and 17.2% for 2-3 months.
“For less than 4 weeks, there was no improvement in N or T downstaging,” said Dr. De Andrade. “As the amount of time on NET increased, it was associated with greater T downstaging. But for N downstaging, it was only at the standard of 12 or more weeks that a difference was seen in nodal downstaging.”
Standard NET of 12 or more weeks was associated with reduced mastectomy rates, but mastectomy rates were not lower in short-course NET.
Among patients undergoing breast conservation therapy, longer duration NET was also associated with a lower risk for re-excision (1-2 months: odds ratio, 0.82, P = .02; 2-3 months: OR, 0.40, P < .001). There was no reduction in re-excision for shorter courses of therapy.
Dr. De Andrade had no disclosures.