Breast cancer worse among obese women

Obesity, particularly central obesity, seems to correlate with a more aggressive breast cancer (BC) phenotype, a recent study has found. The impact of breast volume, on the other hand, is less clear.

A total of 347 pre- and postmenopausal women who had recently been diagnosed with BC participated in the study. Approximately a third (35.4 percent) had body mass index (BMI) >30 kg/m² and were considered obese, while 60.20 percent were deemed to be centrally obese, defined as a waist-hip ratio ≥0.85. In 44.7 percent, breast volume was >600 cc and qualified as large.

In obese participants, tumours exceeding 2 cm occurred significantly more frequently (45.5 percent vs 40.6 percent; p=0.04), as did axillary involvement (53.84 percent vs 38.80 percent; p=0.04). In addition, undifferentiated tumours were significantly more common in the obese group (38.2 percent vs 23.2 percent; p=0.01). Obesity also worsened scores in the Nottingham prognostic index (NPI).

Among women with central obesity, higher postsurgical tumour stages were more common (61.7 percent vs 57.8 percent; p=0.03), and axillar invasion occurred at higher rates (39.9 percent vs 36.0 percent; p=0.004).

In addition, central obesity also coincided significantly with greater lymphovascular infiltration (6.5 percent vs 1.6 percent; p=0.02), more undifferentiated tumours (30.0 percent vs 22.3 percent; p=0.009), and worse NPI (p=0.04).

Breast volume only seemed to affect receptor status. Tumours that were oestrogen receptor-positive occurred more frequently among women with large breast volumes (91.3 percent vs 77.1 percent; p=0.04).

“Our results justify the performance of a simple, fast, and inexpensive anthropometric measurement in mammary oncology clinical practice; this measure could provide important prognostic information beyond what is obtained through the report of pathology anatomy and clinical evaluation,” the researchers said.