You’ve heard the statistic so often that it’s receded to the background: about 1-in-8 women in the United States will be diagnosed with breast cancer.
What that statistic hides or minimizes: breast cancer is the leading cancer that women face. However, when you break breast cancer into its two distinct forms – ductal and lobular – ductal remains number one. But lobular is number six.

The prevalence of lung and bronchial cancer declines with a decline in smoking cigarettes, but it is still the second most common cancer among men and women.
Invasive lobular carcinoma (ILC, lobular breast cancer) begins in the milk-producing glands (lobules) of the breast. Invasive ductal carcinoma (IDC, ductal breast cancer) begins in the ducts that carry milk from the lobules to the nipple. Invasive means that the cancer has “invaded” or spread to surrounding breast tissues.
Lobular cancer typically does not form a tumor, which can be felt like a lump; lumps are common in ductal breast cancer. Instead, with ILC part of the breast may feel like it has become thicker. Usually, however, there may be no physical symptoms.
About two-thirds of women are 55 or older when they are diagnosed with an invasive breast cancer. Women who are diagnosed with ILC tend to be in their early 60s; women diagnosed with IDC tend to be mid- to late-50s.
In addition to their manifesting in different parts of the breast, ILC and IDC differ genetically and at the molecular level. They respond differently to treatment. And should they metastasize, they tend to do so in different parts of the body.
About 80% of all breast cancers are invasive ductal carcinomas; about 15% are invasive lobular carcinomas.
Lobular carcinoma in situ (LCIS) is a premalignant lesion that indicates increased risk for cancer for either breast.
A systematic review of published studies done by the Agency for Health care Research and Quality revealed that within 5 years after LCIS diagnosis, 4.2% to 9.3% of patients were diagnosed with breast cancer. In studies that followed patients for more than 5 years, the incidence of cancer was 7.7% to 26.3%.
Atypical ductal hyperplasia (ADH) is also a premalignant lesion that increases a women’s risk of breast cancer in the breast where ADH is found.