TOPLINE:

Adjuvant chemotherapy is associated with improved breast cancer-specific and overall survival in women aged 70 years or older with nonmetastatic triple-negative breast cancer, according to a US population-based study. However, fewer than half of patients in that age group receive it.

METHODOLOGY:

• Adjuvant chemotherapy is recommended for women with triple-negative breast cancer (TNBC), but prospective studies have largely excluded older patients. Data on outcomes among patients aged 70 years or older, who often face increased risks for chemotherapy toxicity, are scarce.
• To investigate, researchers used the Surveillance, Epidemiology, and End Results (SEER) database to identify 5730 US women aged 70 years or older who were diagnosed with nonmetastatic TNBC between 2010 and 2021. All underwent surgery and were candidates for adjuvant chemotherapy.
• Overall, 2509 patients received chemotherapy, while 3221 did not. Those who received it were younger (median age, 74 years vs 79 years) and had a slightly higher rate of more-advanced disease (stage II-III, 54.5% vs 51.7%).
• Machine learning was used to estimate propensity scores. Inverse probability of treatment weighting and Cox proportional hazards regression methods were used to compare breast cancer-specific survival (the primary endpoint) and overall survival between the two treatment groups. The median follow-up was 46 months.

TAKEAWAY:

• Adjuvant chemotherapy was associated with improved breast cancer-specific survival (hazard ratio [HR], 0.69; P < .001), with benefit seen among patients in their seventies (HR, 0.65) and eighties (HR, 0.71), but not those aged 90 years or older. Five-year overall survival was higher for patients who received chemotherapy than for those who did not (76.4% vs 60.9%); after adjustment, chemotherapy was associated with improved overall survival (HR, 0.55; P < .001).
• The 5-year cumulative risk for breast cancer death was lower for patients who received chemotherapy than for those who did not (13.3% vs 18.1%). The absolute benefit was greatest for patients with stage III cancer (35.1% vs 49.6%) and smallest for those with stage I disease (6% vs 7%).
• Increasing age was associated with a lower likelihood of receiving adjuvant chemotherapy. Compared with patients in their seventies, the odds ratio for patients aged 80-89 years was 0.15, and for patients aged 90 years or older, it was 0.02.
• Overall, adjuvant chemotherapy use increased over time, though only among patients aged 70-79 years, whose rate rose from 44.4% in 2010 to 61.4% in 2021.

IN PRACTICE:

“Adjuvant chemotherapy was associated with improved survival outcomes. Underutilization of adjuvant chemotherapy in older women may contribute to worse outcomes,” the study authors wrote. They noted that geriatric assessment tools could help identify older patients who are good candidates for adjuvant chemotherapy but also stressed the importance of discussing patients’ values around the potential benefits of chemotherapy vs the risk for toxicities.

SOURCE:

The study, led by Jesus D. Anampa, MD, MS, Montefiore Einstein Comprehensive Cancer Center, Bronx, New York, was published online in JAMA Network Open.

LIMITATIONS:

The analysis is subject to the inherent biases of its retrospective design. The SEER database does not provide information about chemotherapy regimens, duration, or dose modifications, all of which may affect treatment efficacy. The researchers were unable to adjust for patient comorbidities or polypharmacy and only had data on area-level, not individual-level, socioeconomic factors.

DISCLOSURES:

The study was funded by the US National Institutes of Health. The authors reported having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.