Posted 3/22/2007 12:42 AM (GMT 0)
Let me know if this helps…. And if not I’ll be happy to delete this post….
**Excerpts taken from “Dr. Patrick Walsh’s Guide to Surviving Prostate Cancer”
by: Patrick C. Walsh, M.D. (Professor of Urology, The Johns Hopkins Medical Institutions)
and Janet Farrar Worthington. Copyright 2001
Page 145
**What about Perineural Invasion?
As cancers grow, they compress normal tissue, looking for “elbow room”—spaces with less resistance, where they can spread. Nerves are usually surrounded by some empty space; for cancer, this is the real estate equivalent of a nice suburban lot with a big backyard—plenty of elbow room. Thus, it’s not uncommon to find prostate cancer in the spaces around the nerves; this is called ‘perineural invasion.” Because the nerves are most common close to the surface of the prostate, the findings of perineural invasion on a biopsy suggests that the cancer is close to the edge of the prostate, and may well have penetrated the capsule. However—this is important to keep in mind—cancer that has penetrated the capsule can still be cured. Which makes this a paradoxical finding—because, although men with perineural invasion are more likely to have capsular penetration than men without it, perineural invasion has no long-term impact on whether or not a man can be cured. For this reason, some noted pathologists have suggested that it should not even be commented on when found in a biopsy, because it’s not worth worrying about.
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Page 289-290
**Excerpts taken from “Dr. Patrick Walsh’s Guide to Surviving Prostate Cancer”
by: Patrick C. Walsh, M.D. (Professor of Urology, The Johns Hopkins Medical Institutions)
and Janet Farrar Worthington. Copyright 2001
Cancer Control after Radical Prostatectomy
There is no better way to cure cancer that is confined to the prostate than total surgical removal. This is the “gold standard” of treatment, what all other forms of treatment attempt to accomplish. Thus, it’s important that you understand the results of radical Prostatectomy—just what it can and cannot do—and the fine points in interpreting these results, before you can make an informed evaluation of other treatment approaches.
Start with the facts: The first indisputable fact here is that for any form of treatment to cure prostate cancer, it must be curable in the first place. Is your disease curable? We can learn almost everything we nee to know about where you stand before surgery from the Partin Tables—the next best thing to a crystal ball—using your clinical stage, PSA, and Gleason score. After surgery, other information fine-tunes this picture. The pathologist can determine the facts of your cancer—the Gleason score of the entire prostate, for example (as opposed to the educated guess made by examining just a few cores of tissue). From the pathologist, we can learn whether the cancer was organ-confined, whether there was capsular penetration with negative surgical margins (also called “specimen-confined” disease), whether the margins were positive, and whether the seminal vesicles or lymph nodes were involved. All of these factors have a profound impact on the success of treatment.
What are surgical margins, anyway? This is a confusing point for many men. When the prostate is removed, it should be covered by several layers of tissue. It may help to think of the cancerous prostate as a gift box (although it’s not much of a present), and the tissue surrounding it as wrapping paper. After radical prostatectomy, your prostate goes to the pathologist, who immediately coats the outside of the entire specimen—the wrapping paper—with India ink. The prostate is then put in fixative for twenty-four hours before it is sectioned, stained, and examined under the microscope. The India ink creates a landmark, so the pathologist can figure out exactly how far the cancer has spread. It is contained inside the wrapping paper? If the cancer is all contained within the box, we call it organ-confined. Even if cancer penetrates the box (this is capsular penetration), it can still be completely covered with wrapping paper. We call this specimen-confined. This is an important concept. For example, in men with a Gleason score of 6 or below, the long-term outcome is just as good in men with cancer that’s confined inside the prostate (inside the box) as it is in men who have capsular penetration, but negative surgical margins. If the cancer has penetrated the box and the wrapping paper as well, this is called a positive surgical margin. The pathologist can see cancer cells at the edge of the India ink, and this suggests that there may be cancer beyond the outermost edge where the surgeon removed the prostate.
When surgical margins are positive, or too close to call:
In an ideal world, the pathologist would immediately send a triumphant report to the surgeon: “I’ve looked at the prostate tissue you removed from Mr. Jones, and all the edges are clear. Congratulations! You’ve removed all the caner!”
Fortunately, it often happens that way. At Johns Hopkins, fewer than 10 percent of the patients are found to have cancer at the margins—the edges of the removed tumor. Sometimes, however, the pathologist’s report is more ambiguous. The report states that the margins are “close,” meaning that cancer is just a hairbreadth away from the edge of the specimen.
Expert pathologist Jonathan Epstein, of Johns Hopkins, has good news about these margins:
Close margins are almost always negative. Epstein recently finished a study of men whose tumors were particularly close—less than two tenths of a millimeter—from the surgical margin. Even though there wasn’t a comfortable cushion of tissue between the tumor and the edge of the prostate, “those patients do just as well as if there’s more separation between the tumor and the margin.”
Even if the surgical margins are positive, this does not necessarily mean that cancer is left behind. How can this be? “There are several different explanations why, when the margins are positive, the tumor may still be cured,” says Epstein. “One is that literally, you cut across the last few tumor cells”—that what appears to be remaining cancer is actually a cross section of the perimeter of the tumor. “And even thought it looks like it’s a positive margin, there’s really no cancer left in the patient.”
Another explanation is that the act of surgery itself finishes the job, killing any remaining cells. No cut or injury to tissue happens in a vacuum: the area around the cut is affected, too. (Think of lightning striking a tree; the tree dies, but so does a ring of grass around it.) “When the surgeon cuts across tissue, the blood supply is cut off, there’s dead tissue, and that can kill off the last few tumor cells that might have been left behind,” Epstein says.
There’s also the potential, “and this probably accounts for a lot of cases,” that it’s an “artifact”—basically, a false positive margin. Sometimes, “since there’s so little tissue next to the prostate, when the surgeon tries to dissect it from the body, and hands it to the nurse, and then the nurse hands it to the pathologist, everyone’s touching the gland. If you’re talking about two tenths of a millimeter of tissue, that tissue can be disrupted very easily. It can appear that the tumor is at the margin—but in fact, there was some additional tissue there that just got disrupted during all the handling.” In other words, a few good “buffer” cells got rubbed off.
And then there’s the sticky cell phenomenon. When cancer reaches beyond the prostate to invade nearby tissue, it produces a dense scar tissue that acts like super-glue. As a surgeon removes the prostate, this think scar tissue sticks to the surrounding caner cells—picking them up like a lint brush. So in some cases, although the pathologist may see cancer cells at the margin—and make a judgment of “positive surgical margins”—there are no cancer cells left inside the patient. The sticky scar tissue took them all away.
Epstein recently studied such instances, where the surgeon removed the prostate, looked at it, suspected that some cancer cells were present, went back and cut out more of the surrounding tissue. “So in pathology, we got two separate specimens,” says Epstein. “One was the prostate, one was this extra tissue, the neurovascular bundle that the surgeon was thinking of leaving in the patient, but decided to remove.” Even when there appeared to be a positive surgical margin at the edge of the prostate, in 40% of these patients, there turned out to be no cancer left behind in that adjacent tissue.
“So when pathologist call a positive margin, or for that matter, a close margin, it doesn’t necessarily mean that these patients need some other form of therapy, like radiation—and also that they need not necessarily be tremendously worried.”
**Excerpts taken from “Dr. Patrick Walsh’s Guide to Surviving Prostate Cancer”
by: Patrick C. Walsh, M.D. (Professor of Urology, The Johns Hopkins Medical Institutions)