Noninvasive versus invasive

Published Oct 5, 2017 at 12:00pm

Upon diagnosing a patient with breast cancer, a physician will order a series of tests in order to get a profile of the breast cancer, including how it looks and how it is likely to behave. The doctor will receive a pathology report from the tests, that helps map out a course of treatment. The pathology report also may help breast cancer patients better understand their disease and why their doctor is choosing one course of treatment over another.

A pathology report can reveal a host of information about a patient’s breast cancer, including whether that cancer is noninvasive or invasive. This is an important distinction, as treatment plans for noninvasive and invasive cancers can differ significantly. 

Noninvasive breast cancers stay within the milk ducts or lobules in the breast. This is significant, as breast cancer is very treatable when detected early and tests find only localized, noninvasive tumors.

Invasive breast cancers are those that spread outside the membrane of the lobule or duct and into the breast tissue. The cancer can then spread into the lymph nodes in the armpits or beyond. Invasive breast cancers are more common and are most often one of two types. 

• Invasive ductal carcinoma, or IDC, starts in a milk duct before breaking through the duct walls and invading fatty breast tissue. IDC, which accounts for 80 percent of invasive cancers, can remain near the site where the tumor originated, but cancerous cells also may enter the bloodstream or lymphatic system and spread anywhere in the body.

• Infiltrating lobular carcinoma, or ILC, is considerably less common than IDC, accounting for roughly 10 to 15 percent of invasive breast cancers. ILC begins in the lobules and milk glands before spreading in much the same way as IDC.

Some breast cancer cases may be classified as both noninvasive and invasive. Such a classification means that part of the cancer has grown into normal tissue while another part of the cancer has stayed within the milk ducts or lobules. Doctors developing treatment plans for such cases will treat them as invasive cancers.

It’s easy for men and women to be overwhelmed when diagnosed with breast cancer. But understanding the disease can make it easier to comprehend treatment plans and beat the disease.