Washington, March 14 (IANS) Overweight and obese women tend to develop more aggressive breast cancers with lower survival rates, according to a report in the latest issue of Clinical Cancer Research. “The more obese a patient is, the more aggressive the disease,” said Massimo Cristofanilli of the University of Texas. “We are learning that the fat tissue may increase inflammation that leads to more aggressive disease.”

Cristofanilli and colleagues based their findings on a survey of 606 women with locally advanced breast cancer. They were classified by body mass index into three groups: normal/underweight (BMI 24.9 or below), overweight (BMI at least 25 but less than 30) or obese (BMI more than 30). BMI or body mass index is calculated by dividing a person’s weight by his or her height.

At five years, overall survival was 56.8 percent among obese women, 56.3 percent among overweight women and 67.4 percent among normal weight women.

The 10-year survival rate was 42.7 percent among obese women, 41.8 percent among overweight women and 56.5 percent among normal weight women.

The rate of inflammatory breast cancer, previously shown to have worse outcomes than non-inflammatory breast cancer, among obese women was 45 percent compared with 30 percent in overweight women and only 15 percent in women considered normal weight, researchers found.

Risk of breast cancer recurrence was also higher in obese or overweight women. By five years later, 50.8 percent of obese women reported a recurrence compared with 38.5 percent of normal weight women. By 10 years, the rate of recurrence was 58 percent among obese women and 45.4 percent among normal weight women.

Cristofanilli said that physicians should to pay close attention to such patients because commonly used drugs, like tamoxifen, tend to increase weight during treatment.