USORTC-9735 trial

Background

Phase III RCT enrolled 1,016 women with stage I-III operable breast cancer (T 1.0-7.0 cm) after surgery, comparing an anthracycline-free regimen (TC) with standard AC.

Interventions and follow up

Arm A: Docetaxel/cyclophosphamide (TC) 75/600 mg/m2 q3wk x4
Arm B: Doxorubicin/cyclophosphamide (AC) 60/600 mg/m2 q3wk x4
Primary endpoint: Disease-free survival (DFS)
mFollow up: 5yr (initial); 7yr (update)

Results

5-yr DFS (TC vs AC): 86% vs 80%; HR 0.67; P=.015
5-yr OS (TC vs AC): 90% vs 87%; HR 0.76; P=.13
7-yr DFS (TC vs AC): 81% vs 75%; HR 0.74, 95% CI 0.56-0.98, P=.033
7-yr OS (TC vs AC): 87% vs 82%; HR 0.69, 95% CI 0.50-0.97, P=.032

Adverse events

Hematologic: Febrile neutropenia 5% with TC.
Musculoskeletal: More myalgia, arthralgia, and edema with TC.
Gastrointestinal: More nausea/vomiting with AC.
Cardiac: Cardiotoxicity favored the anthracycline-free TC regimen.

Conclusions

Adjuvant TC provides superior DFS and OS versus AC, establishing an effective anthracycline-free option.

Key Limitations

No HER2/biomarker stratification (predates routine HER2 testing); heterogeneous receptor subtypes. Modest sample size limits subgroup inference. Comparator AC x4 is a low-intensity anthracycline regimen, not a taxane-anthracycline sequence.

Clinical Context

Established TC x4 as a standard anthracycline-free adjuvant regimen, widely endorsed by ASCO/ESMO for lower-to-intermediate-risk early breast cancer where anthracycline avoidance is preferred (cardiac risk). 7-yr update (Jones S et al, JCO 2009; PMID:19204201) confirmed durable OS benefit.

References