High BMI linked to larger breast cancer tumor size

BMI was the only consistent risk factor for detecting breast tumors larger than 2 cm among women, according to findings being presented at next week’s annual meeting of the Radiological Society of North America.

“Ever since breast cancer screening was introduced there has been a debate about its utility,” Fredrik Strand, MD, radiologist at the Karolinska University Hospital in Stockholm, Sweden, wrote in an abstract. “We aimed to identify risk factors associated with tumors not being detected until larger than 2 cm, and to examine the implications for longterm prognosis.”

Researchers conducted a populationbased screening cohort of 2,012 cases of invasive breast cancer between 2001 and 2008. They followed up with the patients until 2016, and determined ageadjusted HRs for disease progression: either distant metastasis, locoregional relapse, or death due to breast cancer.

Strand and colleagues found that for screendetected cancers, both percent density (OR = 1.26 per 10% density) and BMI (OR = 1.33 per 5 kg/m²) were associated with a patient having a large tumor at diagnosis. For interval cancers, only BMI (OR = 1.56) was associated with having a large tumor, while percent density (OR = 0.81) was linked with having a small tumor.

In addition, large tumors were linked to worse prognosis than smaller tumors (HR = 2.66). Among interval cancers only, women with higher BMI had worse prognosis than those women with lower BMI (HR = 2.01). Nulliparity was only significant among screendetected cases (OR = 1.45). Percent density showed no significant link with disease progression.

“Our study suggests that when a clinician presents the pros and cons of breast cancer screening to the patient, having high BMI should be an important argument,” Strand said in a press release. “In addition, our findings suggest that women with high BMI should consider shorter time intervals between screenings.”

He added that the molecular composition of the tumors and hormone receptor expression levels in women with high BMI could lead to a worse prognosis. – by Janel Miller

Reference: Strand F, et al. BR252-SD-WEB1. Presented at: Radiological Society of North America Annual Meeting. Nov. 26–Dec. 1, 2017; Chicago.

Disclosures: Healio Family Medicine was unable to determine the authors’ relevant disclosures prior to publication.