Lymphovascular invasion (LVI) is a finding made by a pathologist when examining cancerous tissue under a microscope. It means that cancer cells have entered the body’s lymphatic or circulatory systems. When cancer cells are found inside these vessels, it suggests they can move away from the primary tumor. These vessel networks can be thought of as highways that allow cancer cells to travel from their original location. This finding provides information about the cancer’s behavior, indicating it has a mechanism to potentially travel.
The Biological Process of Invasion
The lymphatic system is a drainage and filtration network carrying lymph, a fluid containing white blood cells for immune defense. The vascular system, composed of arteries, veins, and capillaries, transports oxygen and nutrients. While normally protective, both systems can be exploited by cancer cells.
For LVI to occur, cancer cells must undergo a series of biological steps. First, cells at the tumor’s edge must detach from the main mass, which involves the loss of cell-to-cell adhesion molecules. These mobile cells must then break down the extracellular matrix, a scaffold-like structure supporting cells in tissues.
Once free, the cancer cells move toward nearby lymphatic or blood vessels. They then penetrate the vessel wall to enter circulation. To do this, cancer cells can produce enzymes to degrade the vessel’s lining or interact with the endothelial cells that form the wall, causing them to separate and create an opening. Once inside, the cells can travel through these channels to other parts of the body.
Diagnosis in Pathology
The identification of lymphovascular invasion is a microscopic finding, not a condition that produces symptoms or can be seen on imaging scans like CTs or MRIs. A pathologist discovers it after a tissue sample, from a biopsy or surgery, is sent to a laboratory for analysis.
In the lab, the tissue is processed into thin slices, placed on glass slides, and stained with dyes. The most common stain is hematoxylin and eosin (H&E), which gives the cells and surrounding structures different colors, allowing the pathologist to see them clearly. The pathologist scans these slides, looking for tumor cells located inside an endothelium-lined space, which is the hallmark of a blood or lymphatic vessel.
Confirming LVI requires careful observation to distinguish it from possibilities like tissue shrinkage during processing, which can create artificial spaces. In cases where an H&E stain is not definitive, the pathologist may use immunohistochemistry (IHC). This method uses specific antibodies to highlight the endothelial cells lining the vessels, providing clear proof that cancer cells are located within them.
Impact on Cancer Prognosis
The presence of lymphovascular invasion is a prognostic factor, providing information about the likely course of the cancer. Its detection signifies that the cancer can access the body’s transportation networks, a necessary step for metastasis. The presence of LVI is associated with a higher risk that cancer cells may have traveled to regional lymph nodes or more distant organs.
It is a risk factor that oncologists consider when assessing a cancer’s behavior. The predictive value of LVI can vary depending on the specific type of cancer. For some cancers, it is a strong independent predictor of a poorer prognosis, while for others, its significance is debated.
Doctors use information about LVI in combination with other pathological features to build a risk profile for each patient. These other factors include the size of the primary tumor, its histological grade, and whether cancer is present in the lymph nodes. By integrating all of this data, the medical team can more accurately estimate the risk of recurrence.
Influence on Treatment Planning
Lymphovascular invasion itself is not directly treated; its presence helps guide the overall treatment strategy for the primary cancer. Finding LVI on a pathology report signals to the oncology team that the cancer may be more aggressive, prompting a proactive approach to management. This allows doctors to tailor a treatment plan aimed at reducing the risk of the cancer returning or spreading.
If LVI is found in a surgically removed tumor, it may raise concerns about micrometastases—tiny deposits of cancer cells that are too small to be detected. In such cases, a doctor might recommend adjuvant therapies. This could include chemotherapy to target any stray cancer cells or radiation therapy focused on the area where the tumor was removed.
The presence of LVI can also influence surgical decisions. A surgeon might opt for a wider excision, removing a larger margin of normal tissue around the tumor site. It may also prompt a more extensive examination of the lymph nodes, such as a sentinel lymph node biopsy or a more comprehensive lymph node dissection. Identifying LVI allows the medical team to create a more precise and effective treatment plan.