254P - Effects of delaying adjuvant chemotherapy initiation on clinical outcomes in early triple-negative breast cancer patients

Background

TNBC is known for its aggressive nature, with early recurrence and limited treatment options beyond chemotherapy and recently immunotherapy. The optimal time to initiation of adjuvant chemotherapy (TTAC) for triple-negative breast cancer (TNBC) patients remains unclear. We aim to clarify, whether TTAC has an impact on survival in patients with early TNBC.

Methods

Data from a large population-based regional cancer registry covering over 2.2 million people was used for evaluation, including women with diagnoses of TNBC between 2010 and 2018. Data collected included demographics, pathology, treatment, recurrence, and survival. TTAC was defined as days from primary surgery to first dose of adjuvant chemotherapy. Kaplan-Meier and Cox regression methods were used to evaluate impact of TTAC on overall survival (OS).

Results

We identified 37 382 patients with malignant neoplasms of the mammary gland. The final study cohort included 732 patients with early TNBC, of whom 43.6% were treated with neoadjuvant chemotherapy and 40.3% with adjuvant chemotherapy. 245 patients with TNBC treated with adjuvant chemotherapy had a valid TTAC. Treatment given within 22-28 days led to the best outcome with a mean OS of 10.2 years, while later treatment (29-35, 36-42 days, or >6 weeks) had significant reduced survival rates of 8.3, 7.8, and 6.9 years. Patients who received therapy within 22-28 days had significantly better survival than those who received therapy between 29-35 days (p=0.043) or after more than 43 days (p=0.033).

Conclusions

The results in this large population-based study indicate that timing of adjuvant systemic therapy can influence OS in TNBC patients, with reduced OS if adjuvant chemotherapy is applied later than 42 days after surgery. To optimize patients’ outcomes, we recommend avoiding a delay of more than 6 weeks when administering adjuvant chemotherapy for early TNBC patients.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.