Scientists have long known that cancers spread to distant organs through the lymphatic system. However, the precise details of this process called metastasis have always remained unclear.
As cancer cells break free from a parent tumor, they are believed to enter and travel across the entire system via lymph vessels. Some of these cells ultimately settle in the lymph nodes, while others meet their deaths before infecting other body parts.
Still, one or two of these harmful cells will manage to survive and find a new host organ where they can grow and eventually form malignant tumors.
The widely accepted theory was proposed in 1889 by the English surgeon Stephen Paget, and it has remained uncontested until a new study recently discovered a new organ that's even larger than the skin.
Interstitium Research Sheds Light On Metastatic Cancer
The interstitium refers to spaces inside connective tissues covering the entire body including the digestive, respiratory, and urinary tracts.
These spaces were once thought to be dense layers of collagen but upon inspecting the live tissues through Probe-based confocal laser endomicroscopy, a team of medical experts, from various institutions in Pennsylvania and New York City, saw that they're actually open and filled with lymphatic fluid.
Basically, it's the organ and not vessels that facilitate the flow of the fluid to different parts of the body to sustain healthy immune function.
Because the interstitium drains out into the lymphatic system, cancer cells that penetrate it have increased chances of spreading to lymph nodes or to other organs. They may also stay and grow within the tissue layer.
Although it disproves the role of vessels in coursing lymphatic fluid throughout the body, the recent study supports Paget's idea that cancer cells are similar to plant seeds. For them to grow in a new organ, it must be in a fertile or in a favorable condition.
Instead of bringing a pivotal change to cancer research, the paper published on March 27 in the electronic journal Science Reports adds a missing piece to the medical puzzle that has kept scientists chasing answers for decades.
Discovery Help Develop A More Direct Method In Cancer Testing
At present, cytology tests can be processed using a patient's urine, sputum, spinal fluid, pleural fluid, pericardial fluid, and ascitic fluid.
In contrast to biopsy, this method of cancer testing is more affordable and less invasive. It also comes with a smaller risk of triggering severe complications. However, cytopathology has a downside. In some cases, the American Cancer Society warns it may produce inaccurate results.
Besides contributing to cancer research, the groundbreaking discovery of the human body's 80th organ can help in the development of another non-invasive method that works more effectively.
"This finding has potential to drive dramatic advances in medicine, including the possibility that the direct sampling of interstitial fluid may become a powerful diagnostic tool," says Neil Theise, a Pathology professor at NYU Langone Health and co-senior author of the study.
The team asserts that other scientists may have already stumbled about the interstitium before. They just couldn't determine what it is. According to a report, they are reviewing previous studies to obtain more information on the new organ.