Obesity Tied to Higher Risk of Breast Cancer Recurrence on Aromatase Inhibitors

Breast cancer patients with obesity may derive less of a benefit from aromatase inhibitors than patients of a “healthy” weight, according to researchers.

The team found that obesity was associated with a higher risk of recurrence in postmenopausal patients with hormone receptor (HR)–positive, early-stage breast cancer who were treated with aromatase inhibitors.

These findings were published in JAMA Network Open.

The study included 13,230 postmenopausal women in Denmark who had a primary diagnosis of stage I-III, HR-positive breast cancer. The patients had a median age at diagnosis of 64.4 years.

Patients were divided into groups based on body mass index (BMI) at the time of diagnosis, and:

• 6.5% of patients met criteria for severe obesity (BMI, 35.0 kg/m² or more)
• 14.4% met criteria for obesity (BMI, 30.0-34.9 kg/m²)
• 32.5% met criteria for overweight status (BMI, 25.0-29.9 kg/m²)
• 44.4% were classified as normal weight (BMI, 18.5-24.9 kg/m² )
• 2.2% were classified as underweight (BMI below 18.5 kg/m²).

Follow-up began 6 months after breast cancer surgery. At a median follow-up of 6.2 years, there were 1587 cases of recurrence.

In a multivariable analysis, patients had an increased risk of recurrence if they had obesity (adjusted hazard ratio [aHR], 1.18; 95% CI, 1.01-1.37) or severe obesity (aHR, 1.32; 95% CI, 1.08-1.62).

There was a trend toward an increased risk of recurrence among patients with overweight status, but the association was not significant (aHR, 1.10; 95% CI, 0.97-1.24).

Underweight patients had a similar risk of recurrence as patients with a normal BMI (aHR, 1.12; 95% CI, 0.77-1.64).

“The results of this novel, large population-based cohort study support previous research suggesting that patients with obesity treated with adjuvant AIs [aromatase inhibitors] may derive less benefit from their adjuvant endocrine therapy than patients with healthy weight,” the researchers wrote.

Disclosures: One study author declared affiliations with Novartis. Please see the original reference for a full list of disclosures.

Reference

Harborg S, Cronin-Fenton D, Jensen MBR, Ahern TP, Ewertz M, Borgquest S. Obesity and risk of recurrence in patients with breast cancer treated with aromatase inhibitors. JAMA Netw Open. Published online October 13, 2023. doi:10.1001/jamanetworkopen.2023.37780

This article originally appeared on Cancer Therapy Advisor