Maintaining a normal weight when you have diabetes is often a challenge. Now, a new study suggests that if you're overweight or obese, you might consider getting more frequent mammograms.
That's because Swedish researchers have found that the breast cancers detected within two years of having a normal mammogram were larger in women who had a higher body mass index or BMI. That included women who were overweight (BMI above 25) or obese (30 or higher). A woman 5-5, for instance, who weighs 155 has a BMI of 25.8.
"Women with a BMI above 25 are at increased risk of being diagnosed late—once the breast cancer has already become large," says study co-author Fredrik Strand, MD, a radiologist at Karolinska University Hospital in Stockholm. He presented the findings November 29, 2017, at the Radiological Society of North America annual meeting in Chicago.
For the study, his team looked at about 2,000 cases of invasive breast cancer found between 2001 and 2007. They looked to see if body weight had a bearing on the tumor being larger than 2 centimeters, about the size of a peanut, when it was found, and whether women with these larger tumors fared worse.1
Body weight did have an influence, and larger women did tend to fare worse.
Experts and professional organizations debate the ''ideal'' frequency of mammograms for older women at average risk of breast cancer, with some suggesting them annually and others recommending mammograms every two years.
The new study finding suggests briefer intervals are better for those with a high BMI, Dr. Strand says.
Quantifying & Explaining the Risk
In the study, ''the risk of being diagnosed with a large cancer [above 2 centimeters] is about 50% higher for overweight or obese women,'' Dr. Strand tells OnTrackDiabetes.
Dr. Strand can't say there is a cause-and-effect relationship between excess weight and getting a larger tumor, as he found only a link or association.
And he can't explain the link with certainty, he says, but women with a higher BMI often have larger breasts, and that ''might make it harder to notice a smaller tumor."
The study findings hit home to Wendy Scinta, MD, MS, president of the Obesity Medicine Association, who treats obese patients in her medical weight loss practice in Syracuse, NY. Many of her patients are cancer survivors, she says.
"I think what really increases the risk is that fat cells are very active, and in a negative way, a way that harms the body," she says. "They are pro inflammatory, and inflammation causes a lot of problems, one of which is damage to your DNA."
"Fat tissue produces increased levels of estrogen," she says, and most breast cancers are related to high estrogen levels, which helps the cancer cells thrive.
Among her patients, she says, some obese women may feel uncomfortable getting mammograms, not just due to the compression of the breasts, which can be uncomfortable, but because they feel uncomfortable about their size and disrobing.
At her initial visit with an overweight or obese woman, Dr. Scinta says, she asks for the date of their last mammogram.
After menopause, being overweight or obese does increase the risk of breast cancer, according to the American Cancer Society.2
Various organizations suggest different intervals for screenings for breast cancer. While his study did not look at the ideal interval, Dr. Strand says that it seems a two-year interval might be too long. "It seems to be that it is especially important for women with high BMI to participate in mammography screening programs."