Originally published 4/30/2016
It’s hard to believe it’s been over 5 years since we posted a blog on the topic of prostate cancer (PCa) spread due to the surgeon’s knife. Since then, we have posted blogs on a related topic, the “seeding” of PCa beyond the prostate capsule into biopsy needle tracks. It has been, and continues to be, our position that metal instruments such as a scalpel or a biopsy needle are extremely unlikely to unleash PCa tumor cells that ultimately threaten a patient’s life. The predominant opinion among clinical professionals is that, even if it were to occur, it would be exceedingly rare.
Another way to come at the prostatectomy-spreading-PCa problem is to broaden the question: can surgical removal of cancer cause the cancer to spread? A 2017 article by Tohme, et al. explores “concept that surgery to eliminate the cancer can actually serve to increase the establishment of new metastases and accelerate growth of residual and micrometastatic disease.”[i] The authors explain several conditions that can occur during the perioperative period (hospitalization period before, during and after a cancer operation) to trigger cancer spread, and in fact this period has been observed to foster increased tumor activity. The points about surgery include:
- It induces increased shedding of cancer cells into the circulation
- It suppresses anti-tumor immunity allowing circulating cells to survive
- It switches on the production of adhesion molecules in target organs
- It triggers changes in the target tissue and cancer cells themselves to enhance migration and invasion to establish at the target site.
This is not surprising, since surgery is a traumatic invasion to which the immune system responds with local and systemic inflammatory processes that favor tumor activity.
The authors do not mention surgical instruments (scalpels, etc.) as specific physical transmitters of tumor cells. The author of a PCa blog, however, opines, “Some cancers are easily spread through inoculation by surgical instruments. For this reason, surgeons try to avoid cutting into the tumor.”[ii] Since there is no research citation, it’s unclear where he got that information. He notes that in the case of positive surgical margins, the tumor has been cut into so possibly PCa cells that are left behind can grow into recurrence. If so, it may well be because of the enhanced conditions described in the Tohme article. Nonetheless, even that author concedes we don’t have a way to distinguish “a cancer placed by instrumentation from one that grew there naturally.”
Therefore, we conclude that it’s still unknown if surgical removal of a prostate gland can actually cause recurrence or spread—and if so, is the scalpel the actual culprit? In any case, we find consolation in knowing that it’s extremely rare among patients for whom surgery is the best treatment plan.
To be honest, the question does not have a clear answer. I read one journal article in which “surgical manipulation” of the prostate gland during radical prostatectomy (RP) increased the number of circulating tumor cells (CTCs, or breakaway tumor cells into blood circulation); it was proven by comparing blood samples before and during surgery. Then I found another journal article showing that robotic assisted RP did not cause an increase in CTCs. Before I go further, here’s what you should know about the chances of cancer spreading on its own.
It is scary to be told, “You have cancer.” No matter how much your doctor reassures you that your cancer is highly treatable, there is always that lurking fear: What if it spreads? You may know of someone who had a malignant tumor removed or radiated—only to find out later that it’s growing somewhere else (metastasis). In fact, it is not easy for cancer to spread because the body is equipped with many defenses against rogue cells. On its own, cancer has to overcome several problems in order to spread. Here are just a few:
- A breakaway cell doesn’t just float free. It has to “crawl” into solid barriers posed by surrounding healthy tissues, where it has to “degrade” those tissues to make room for itself.
- If it manages to penetrate through a blood vessel wall, it is swept into an unfavorable fast-flowing environment where it is more likely to die off or be killed by the immune system.
- If it survives in the bloodstream, it must attach to the inside lining of a blood vessel, from which it has to work its way out into a more favorable “host environment.” If it gets that far, it has to attach to tissues that are different than its home tissues, requiring adaptation.
Of course, it is a reality that some CTCs do get past these and other obstacles in order to implant and clone themselves somewhere else. Science now has the ability to detect CTCs in the blood. Several of these “liquid biopsy” tests are available and more on the way. (Note: they don’t take the place of a needle biopsy.) Low risk prostate cancer tumors may not have detectable CTCs at first, but as a tumor enlarges and becomes more aggressive, the number of CTCs will increase. According to experts, “Circulating tumor cells (CTCs) in the blood stream play a critical role in establishing metastases.”[i] This brings me back to the issue of whether or not RP releases CTCs into the bloodstream during surgery.
As I said at the beginning, there are two sides to the issue. It seems that the more invasive a surgery is, the greater the risk of disturbing the tumor and its blood vessels, thereby aggravating the release of cancer cells. As far as I can tell, no one knows for sure. However, there is a feature of heat-based ablations that works against metastasis, and that is the extreme temperature. This is true of our Focal Laser Ablation (FLA). Burning not only destroys the tissue, it also closes off blood vessels. When the laser is switched on, FLA expands in all directions so rapidly that it quickly encompasses the tumor plus a margin of safety. Unlike a scalpel cutting away tissue, nothing that exists within that globe of heat can survive or break away.
I have not yet encountered any articles on heat ablation and CTCs, but I would certainly welcome the research. In the meantime, I have confidence that the FLA procedure is highly unlikely to spread cancer.
NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.
[i] Tohme S, Simmons RL, Tsung A. Surgery for cancer: a trigger for metastases. Cancer Res. 2017 Apr 1:77(7): 1548-52.
[ii] “Can Invasive Procedures Spread Prostate Cancer?” The ‘New’ Prostate Cancer Infolink, Jan. 8, 2015.
[iii] Hong B, Zu Y. Detecting Circulating Tumor Cells: Current Challenges and New Trends. Theranostics. 2013;3(6):377-394. doi:10.7150/thno.5195.