ASO Author Reflections: Objective Response Rate after Short Duration (< 9 Weeks) Is Not Inferior to Moderate (9-27 Weeks) or Long Duration (> 27 Weeks) of Neoadjuvant Endocrine Therapy (NET)-An NCDB Analysis.

Past

In the United States, the use of neoadjuvant endocrine therapy (NET) is infrequent and often reserved for patients who cannot tolerate neoadjuvant chemotherapy (NAC) despite a similar efficacy and lower toxicity compared with NAC.1,2 Historically, the most common NET duration used in clinical trials and in practice has been reported to range from 12 to 24 weeks.2,3 The objective response rate (ORR) of a shorter NET duration is unclear.

Present

Use of NET has seen a resurgence since national medical/surgical organizations recommended its use to bridge surgery delays during the COVID-19 pandemic. NET duration is expected to vary but likely to be < 12 weeks in most treatment locations. Using the National Cancer Database (NCDB), we found that NET utilization rose steadily from 1% in 2010 to 1.3% in 2016 and that a shorter duration of NET (< 9 weeks) was used in 25% of patients receiving NET. When stratifying NET by short (< 9 weeks), moderate (9–27 weeks), and long duration (> 27 weeks), we found that the ORR was 56.7%, 52.1% and 49.0%, respectively, suggesting oncologic safety of NET even when used for < 9 weeks.4

Future

Several questions remain unanswered: (1) How is NET affecting adjuvant therapy recommendations during the pandemic? Specifically, does NET change recurrence score (RS) results in the treated tumor? Whether RS in the pre- and post-treatment tumor remains the same is unclear.5 At our institution during the pandemic, a multidisciplinary team convened frequently (more than weekly) to discuss optimal local and systemic treatment for new patients using several caveats. Systemic therapy recommendations for patients with hormone receptor (+) breast cancer were influenced by possible effects of NET on sampled axillary nodes, RS score derived from pre-treatment tumor tissues, and NCCN guidelines. (2) How does the interaction between surgery delay and NET affect long-term outcomes? Regional and national organizations are actively collecting data to address this question.

In conclusion, our results showed that short NET duration did not result in an inferior ORR. Though reassuring, future studies to assess effect of NET on clinical outcomes will confirm the oncologic safety of NET to bridge surgery delay.