Vascular or Lymphatic System Invasion on breast cancer protection

The breast has a network of blood vessels (called the vascular system) and lymph channels (lymphatic system) that carry blood and fluid back and forth from your breast tissue to the rest of the body. They are the "highways" that bring in nourishment and remove used blood and the waste products of cell life.
Vascular or lymphatic system invasion happens when breast cancer cells break into the blood vessels or lymph channels. This increases the risk of the cancer traveling outside the breast or coming back in the future. Doctors can recommend treatments to help reduce this risk.
Your pathology report will say “present” if there is evidence of vascular or lymphatic system invasion. If there is no invasion, your report will say “absent.” Lymphatic invasion is different from lymph node involvement. The lymph channels and lymph nodes are part of the same system, but they are looked at and reported separately.
Grade is a “score” that tells you how different the cancer cells’ appearance and growth patterns are from those of normal, healthy breast cells. Your pathology report will rate the cancer on a scale from 1 to 3:

• Grade 1 or low grade (sometimes also called well differentiated): Grade 1 cancer cells look a little bit different from normal cells, and they grow in slow, well-organized patterns. Not that many cells are dividing to make new cancer cells.
• Grade 2 or intermediate/moderate grade (moderately differentiated): Grade 2 cancer cells do not look like normal cells and are growing and dividing a little faster than normal.
• Grade 3 or high grade (poorly differentiated): Grade 3 cells look very different from normal cells. They grow quickly in disorganized, irregular patterns, with many dividing to make new cancer cells.

Having a low-grade cancer is an encouraging sign. But keep in mind that higher-grade cancers may be more vulnerable than low-grade cancers to treatments such as chemotherapy and radiation therapy, which work by targeting fast-dividing cells.
Be careful not to confuse grade with stage, which is usually expressed as a number from 0 to 4 (often using Roman numerals I, II, III, IV). Stage is based on the size of the cancer and how far it has (or hasn’t) spread beyond its original location within the breast.
Your pathology report may include information about the rate of cell growth — what proportion of the cancer cells within the tumor are growing and dividing to form new cancer cells. A higher percentage suggests a faster-growing, more aggressive cancer, rather than a slower, “laid back” one. Tests that can measure the rate of growth include:

• S-phase fraction: This number tells you what percentage of cells in the sample are in the process of copying their genetic information, or DNA. This S-phase, short for “synthesis phase,” happens just before a cell divides into two new cells. A result of less than 6% is considered low, 6-10% intermediate, and more than 10% is considered high.
• Ki-67: Ki-67 is a protein in cells that increases as they prepare to divide into new cells. A staining process can measure the percentage of tumor cells that are positive for Ki-67. The more positive cells there are, the more quickly they are dividing and forming new cells. In breast cancer, a result of less than 10% is considered low, 10-20% borderline, and high if more than 20%.

Although the S-phase fraction and Ki-67 level may provide you and your doctor with useful information, experts don’t yet agree on how to use the results when making treatment decisions. Therefore, not all doctors order these tests routinely, so they may not appear in your pathology report. The other results in your report will be much more important in making informed choices. (If you decide to have an Oncotype DX test to check the likelihood of cancer coming back and whether you could benefit from chemotherapy, Ki-67 will be included in that panel of testing.)