Okay, I have a feeling this is a really stupid question, so at the very least, I’ll have provided some DoperDocs/Nurses/Med Students a bit of amusement at my stupidity.
In a biopsy, as I understand it, the idea is to get a sample of the “questionable” area to test it for cancer cells. Somehow, I’ve got this image in my head of a balloon (okay, tumors aren’t nice round-shaped balloons, but bear with me) and the needle “pops” the balloon in order to get the cancer cells. But doesn’t this means cancer cells can escape to grow elsewhere?
No, it’s more like a needle/cannula is inserted into the lump, and cells removed. They may inject a small amount of saline to wash out cells, but never having been present for an FNA (I’ve assisted with bone marrow biopsies) I’m not entirely sure. The cells are then taken to the histology (or anatomical pathology) lab, where they are processed, stained and then reviewed by a CT and pathologist. The pathologist will then generate a report that details the type of cells found, and whether they are benign or malignant. The report goes to your doctor, and s/he then discusses the findings with you.
I guess I’m not understanding the nature of tumors…are they solid, like a piece of plastic, or is there bad cells surrounded by something else, like a cherry surrounded by chocolate?
I had a lump scare and when the ultrasound brought back a solid mass, it definitely went in the “that’s bad” column. Apparently fluid-filled breast lumps are almost always non-cancerous cysts. (Biopsy showed it was a benign mass.)
If the bad cells were handily surrounded by a little garbage sack, like the giblets in a processed turkey, surgically removing tumors would be a lot easier. They’re just a bunch of cells that may or may not look different from the cells around them to the eye. They’re certainly not under pressure, like in a balloon ready to burst. They’re just…there.
To a large extent, there are two major types of biopsies:
removing a piece of the “lump” and then examining the cells it’s made up of under the microscope (this is what an open, or surgical, biopsy involves)
inserting a thin, hollow needle into the lump, and then sucking up a very, very narrow cylinder of the lump or simply sucking up some loose cells that have fallen off or been dislodged from the lump (this is called a needle biopsy or a fine needle biopsy).
There is, in fact, a risk of spreading cancer cells along the track of a needle biopsy. This is rare but does happen. Certainly, though, the benefits of the biopsy far outweigh the very slight risk of seeding tumor cells along the needle path (e.g. the biopsy can tell if it’s a tumor, and if it is, what the best treatment is).
To give you a sense of the risk, I’ll note that for needle biopsy of lumps in the abdominal area, the risk of tumor cells seeding along the track of the needle is in the order of 0.005% (1 in 20,000) (but increases almost exponentially as the diameter of the needle increases).
I have had occasion to peer over a pathologist’s shoulder as they look at core biopsies or surgical biopsies under a microscope, and I’ve also just finished a course that had a lecture or two about malignant cell growth. Out of those two things, I can tell you that while there is a boundary between a breast tumor and the surrounding tissue, that boundary is most often simply normal vs. not-normal cells. In a given organ, there are thin sheets of collagen and other proteins that help hold together the cells that form a sub-structure, or that help keep the organ together. A breast cancer tumor does not do that normally, as far as I know. Tumors that occur in the liver and thyroid gland sometimes do, though. The appearance and feel of a lump come from the fact that cancer cells divide more rapidly than the surrounding cells. Since they often originate from a single cell that accumulated enough DNA mutations to become malignant, they will stay put in the early stages, growing around that point of origin. They’re squeezing into a space already occupied by normal cells, so in aggregate they’re going to be more dense than the surrounding tissue and thus palpable.
As a side note, my wife had a ductal cyst a few years ago that was filled with fluid. She said she felt a little deflated afterwards, but nothing more. In this case, the cyst did have a capsule that was holding fluid in.