Patients with hormone receptor (HR)-positive, HER2-negative, intermediate-risk, early breast cancer can forgo chemotherapy without increasing their risk of late recurrence, updated results from the TAILORx study suggest.
The data showed that, at a median follow-up of 11 years, outcomes with endocrine therapy (ET) alone remained noninferior to outcomes with chemotherapy plus ET (CET) in this patient group.
One reason researchers conducted this updated analysis was that at least 50% of recurrences happen more than 5 years after diagnosis, said study investigator Joseph A. Sparano, MD, of Mount Sinai Health System in New York, New York, when presenting the update at the San Antonio Breast Cancer Symposium 2022.
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The TAILORx trial (ClinicalTrials.gov Identifier: NCT00310180) enrolled 10,273 patients with HR-positive, HER2-negative, T1c-T2 breast cancer. Patients who had an Oncotype DX recurrence score (RS) of 11-25 were randomly assigned to ET alone (n=3399) or to CET (n=3312). Patients with an RS of 0-10 were assigned to ET, and patients with an RS of 26-100 were assigned to CET.
The primary endpoint was invasive disease-free survival (IDFS). The median follow-up for this analysis was 11 years in the randomized patients and 10.4 years in the overall cohort.
Among the patients with an RS of 11-25, ET remained noninferior to CET for IDFS and other outcomes. The 12-year IDFS rate was 76.8% in the ET arm and 77.4% in the CET arm (hazard ratio [HR], 1.08; 95% CI, 0.96-1.20; P =.19).
The 12-year rate of freedom from distant recurrence was 92.6% with ET and 92.8% with CET (HR, 1.11; 95% CI, 0.90-1.36; P =.34). The 12-year rate of freedom from distant and locoregional recurrence was 89.6% and 90.5%, respectively (HR, 1.15; 95% CI, 0.96-1.36; P =.12). The 12-year overall survival rate was 89.8% in both arms (HR, 1.06; 95% CI, 0.91-1.24; P =.46).
When the researchers looked at patient outcomes by time period (regardless of treatment), the team observed more distant and locoregional recurrences after 5 years than in the first 5 years — 1.05% and 0.70%, respectively.
Dr Sparano concluded that, with longer follow-up, the main study findings remain unchanged for patients with an RS of 11-25. He added that “new findings of this updated analysis, which should be regarded as exploratory, include the fact that late recurrence beyond 5 years exceeded early recurrence.”
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Reference
Sparano J, Gray RJ, Makower D, et al. Trial assigning individualized options for treatment (TAILORx): An update including 12-year event rates. Presented at SABCS 2022. December 6-10, 2022. Abstract GS1-05.
