Delaying adjuvant chemotherapy for breast cancer more than 60 days significantly increases the odds of premature death and distant metastases (Chavez-MacGregor et al)
Most patients are treated with adjuvant chemotherapy for breast cancer within 30-40 days of surgery.
Optimal time for initiation of adjuvant chemotherapy for breast cancer is not precisely defined.
Administration of adjuvant combination chemotherapy within 120 days of diagnosis is considered a quality measure.
Compared to starting adjuvant therapy within 30 days of surgery, initiating chemotherapy at 61 days or later was associated with a 19% increase in the risk of premature death, and in the subgroup of patients with stage III disease, the mortality risk increased by 76%.
In the above analysis of 7000 patients, patients with high-risk breast cancer, triple negative, HER2-positive, or stage III are most susceptible to the adverse effects of delayed chemotherapy.
Patients with triple-negative breast cancer had a 5-year OS estimate of 70% when they started chemotherapy within 30 days, 59% for therapy starting between 31 and 60 days, and 67% for therapy ≥61 days after surgery.
In patients with stage III disease there was a 76% increase in mortality risk if they started chemotherapy ≥61 days after surgery versus 30 days or less.
Patients with the highest-risk features for breast cancer recurrence derive the greatest benefit from adjuvant chemotherapy, and are the most vulnerable to delay in treatment.
In an observational study from the California Cancer Registry with 24,843 patients with stage I-III invasive breast cancer treated with adjuvant chemotherapy: adverse outcomes were associated with delay in the initiation of adjuvant chemotherapy of 91 or more days (MacGregor MC et al).
In the above study the delay time to treatment was particularly detrimental among patients with triple negative breast cancer.