[Jackie07]

http://www.breastcancer.org/symptoms/diagnosis/margins.jsp

The term 'clear margins' is not listed on the link. However, surgeons use the expression all the time. I think it is a perception from the surgeon's point of view - 'the margin is clear, there's nothing [no cancer cells] there'. It also sounds less confusing than a 'negative' margin.

Surgery is usually done 'piecemeal' - tumor tisue is scraped off little by little so the tissues can be checked by the lab to see if cancer cells are present. When the slides of the tissue stop showing the presence of cancer for, say, several millimeters, the surgeon can feel confident that she/he has 'got' all the tumor.

My first surgery, a lumpectomy in 2003, had a 'clear margin' according to my surgeon. Yet 4 years later, we found the recurrence originated from the 'left-over' tumor. My 2nd surgery, a mastectomy in 2007, had a margin of 0.5 mm. A college friend of mine who's a cardiologist warned me about it being too 'narrow'. But my oncologist explained to me that further excision would have damaged my pectoral muscle and paralyzed my right shoulder/arm.

Vessel vascular invasion – the presence of cancer cells in the vessels within the cancer itself.

Once the cancer cells moves to the blood vessels, it gains the access to other parts of the body through the [blood] circulation system. In other words, there's a possibility that the cancer has 'spread'.

'No vascular invasion' means that there's no cancer cells detected in the vessels within the cancer [tumor] itself.

A theory called 'angiogenesis' was introduced many years ago and that's what the use of Avastin was based on. When cancer grows to a certain size, it starts to 'induce' the growth of new blood vessels so it can get 'supplies' to grow. Avastin is used to stop angiogenesis and has proven to be effective in several different types of cancer. However, clinical trials did not show benefit for breast cancer patients.