Dr. Robert Cameron Meso Myth Buster
- Myth #2 -
A more radical operation that takes out the pericardium and diaphragm for bigger margins is a better operation
Some surgeons claim that removing the heart sack (pericardium) and the muscle between the chest and abdomen (diaphragm) are necessary to achieve “adequate” margins in mesothelioma tumor surgery. What is a “margin?” In traditional surgical oncology (cancer surgery), surgeons are trained to remove a reasonable amount of healthy normal tissue around tumors (if such exists) to assure that all the tumor cells have been removed. This is a fundamental surgical oncology practice of obtaining “adequate margins.” The surgeon removes the visible tumor together with a “buffer zone” of normal tissue.
Clean Margins: Fact versus Fiction
Mesothelioma is a tumor that often directly abuts or superficially invades the pericardium and diaphragm as well as all other surfaces within the chest cavity. At first glance, removing the heart sack and diaphragm seems reasonable in order to obtain “adequate margins.”
Yet, as surgeons our ability to achieve these ideal margins in all areas of the chest is simply not possible. Imagine the tumor inside the chest cavity where it quickly spreads over all surfaces like paint spills over a canvas. In essentially all cases, the mesothelioma tumor touches at least one large blood vessel, all of the ribs, spine bones (vertebrae), esophagus (food tube), pericardium, diaphragm, and even the lung.
Near the ribs, vertebrae, esophagus and blood vessels, there is simply no extra normal tissue to remove. Consequently, the best surgeon applying the best technique cannot attain the desired “adequate margin" in these areas.
Strong as the Weakest Link
Another basic principle of cancer surgery is that every operation is only as successful as the “closest margin.” What does that mean? It means that regardless of how much extra normal tissue a surgeon removes in one or more area(s) around each tumor, if even a single other spot lacks an adequate “buffer zone” then the success of the surgery is undermined.
In other words, the overall benefit of the surgery is measured by the inadequacy of that single “close margin,” rather than the positive impact of the other more radical margins elsewhere. In short, the chain is as strong as its weakest link.
This is identical to the effect of even a single dilapidated house on the real estate market prices in an otherwise posh neighborhood. For example a single “eye sore” in Beverly Hills, 90210 brings down the values of all neighboring beautifully-constructed mansions. Analogously, in mesothelioma terms, even a single “poor surgical margin” will ruin the surrounding “estate-like margins”created by removal of the pericardium and diaphragm. I call this phenomenon the “real estate principle of meso margins.”
With this principle as a guide, radical removal of the pericardium and/or diaphragm to improve tumor margins adds no true benefit to any mesothelioma surgical procedure as long as poor margin(s) remain in the area(s) along other vital tissue(s), bone(s), and organ(s), for which no extra margin is anatomically possible.
The bottom line: unfortunately, no mesothelioma surgical procedure exists to date that does not leave such “inadequate margins” somewhere (and virtually always in many areas) in the chest.
Eradication versus Containment and Control
The nature of the mesothelioma tumor itself argues against removal of the pericardium and diaphragm. A more radical surgical technique can't possibly overcome one of the tumor’s basic but most insidious biological characteristics: the fact that mesothelioma relentlessly spreads into virtually any area(s) that are physically connected with the pleural tumor, no matter how small the physical opening.
For instance, surgical incisions and even tiny needle biopsy sites disturb the outer edge of the tumor and permit (and in fact, promote) cancer growth out of the pleural area into previously unaffected tissues crossed by the needle/surgical biopsy. Picture a bucket full of water (chest/pleural cavity filled with tumor) punctured by “biopsy holes” leaking water (tumor) out all over and you get the idea.
The pericardium and diaphragm actually serve as a physical barrier to the spread of the tumor, helping to “contain and surround” the enemy so to speak. Removing them aids and abets the spread of that terrible enemy beyond controllable boundaries. Tragically, surgeons who ardently promote “radical” or “curative” surgery risk spreading the tumor into the pericardial sack and peritoneum (abdominal cavity), making control of the tumor virtually impossible.
Despite this risk, some surgeons claim that they simply cannot remove the tumor off of the pericardium or diaphragm without removing them because the tumor’s penetration is simply too great. They feel that in order to complete the surgery they are forced to “cut it all out.”
Push and Pull, not Cut and Run
Sounds compelling, but neither logic nor reality support this claim. All surgeons remove mesothelioma tumor by literally “pulling and tearing” the tumor off the ribs, vertebrae, blood vessels and even the esophagus. This can be accomplished only because the tumor, for the most part, does not invade deeply into the surrounding normal tissues but instead uniquely “pushes” against them, allowing surgeons to physically separate the tumor from adjacent surfaces.
This “push not penetrate” phenomenon is actually fairly uniform throughout the chest so why would the pericardium and diaphragm be any different? The short answer is: it is not different. In reality (and in my experience), mesothelioma tumor can be stripped off the pericardium and diaphragm in the same manner that it is removed from the other surfaces. Granted, stripping as compared to amputation is far more difficult and tedious technically, as the pericardium and diaphragm, unlike relatively hard and firm ribs, are soft and pliable.
No Absolutes
With appropriate attention and perseverance, pericardium/diaphragm-sparing surgery is achievable. In surgery, as in life however, there are no absolutes. A few patients do have tumor that extends into or all the way through the pericardium and/or diaphragm.
But, in the vast majority of these unusual cases, there are simultaneously multiple other areas of similar tumor invasion and attachment to other tissues, making complete removal of the remaining tumor with or without the pericardium and/or diaphragm essentially impossible.
To summarize: “less can be more” when it comes to mesothelioma surgery. Although “big” operations are touted as better surgery, the appropriate measure of success should be the amount of tissue rationally removed while maintaining critical normal barriers to tumor spread.
The preservation of key anatomic barriers requires extra time, care and effort by the surgeon, but the benefits far outweigh any perceived surgical advantage from their removal. This “less is more” surgical approach is not only sound and rational, but it’s usually achievable, and more often than not, in my view, it better serves the patient’s interests, survival, and quality of life.
Dr. Robert Cameron
January 10, 2011
| Myth #1: | A more radical operation obviously provides better results than a less radical surgical procedure January 3, 2011 |
| Myth #3: | Mesothelioma Tumor in the Lung “Fissures” Cannot Be Removed Without Also Removing the Entire Lung January 27, 2011 |
| Myth #4: | Talc Pleurodesis Prevents Surgeons from Performing a Pleurectomy Operation February 15, 2011 |
Interested in Learning More?
If you have been diagnosed with malignant pleural mesothelioma and would like to learn more about Dr. Cameron’s approach to treating the disease, you may contact his office at (310) 470-8980.
Dr. Cameron sees patients in consultation at his Los Angeles, California clinic located at:
10780 Santa Monica Boulevard
Suite 100
Los Angeles, California 90025-7613
If you are traveling from out of town and would like assistance with travel arrangements, contact the Pacific Meso Center at (310) 478-4678 or info@pacificmesocenter.org.