Lymphovascular invasion (LVI) is a finding noted in cancer pathology reports, representing a biological event occurring at the boundary of a tumor. LVI signifies that cancer cells have gained access to the body’s internal transportation networks. The presence or absence of LVI helps oncologists and pathologists understand a tumor’s potential behavior and aggressiveness. This information guides subsequent medical decisions regarding the pathways a tumor can use to spread.
Defining Lymphovascular Invasion
Lymphovascular invasion is the term for cancer cells entering the body’s vascular or lymphatic channels within or immediately surrounding the primary tumor. The term combines “lymphatic invasion” and “vascular invasion,” which are related biological processes. Lymphatic vessels are thin-walled channels that form a system parallel to the circulatory system, collecting excess fluid and immune cells, and directing them toward the lymph nodes. Vascular vessels, or blood vessels, are the conduits that carry blood throughout the body.
When LVI is identified, cancer cells are located inside these endothelial-lined structures, indicating they have broken through the primary tumor mass. The presence of cancer cells in these channels suggests they have successfully entered the body’s transport system. Pathologists often group lymphatic invasion and vascular invasion together as LVI because small lymphatic vessels and small veins can be morphologically difficult to differentiate under a standard microscope. The presence of cancer cells in either vessel type indicates that the tumor has developed the capacity to use the body’s natural highways for dissemination.
Clinical Significance and Prognostic Impact
The identification of LVI indicates a tumor’s aggressive biological nature and is a significant factor in determining a patient’s prognosis. Its presence signals a higher likelihood that the cancer has already begun the process of metastasis, even if distant spread is not yet detectable by imaging. LVI is strongly associated with an increased risk for regional lymph node metastasis, which are the first major filtering stations for cancer cells traveling through the lymphatic system.
The finding of LVI often correlates with a lower rate of overall survival and a higher risk of the cancer recurring after initial treatment compared to tumors that are LVI-negative. For example, in cases of endometrial cancer, patients with LVI-positive tumors have shown significantly lower five-year disease-free survival rates compared to those without LVI. This is because LVI represents a tumor population that has already demonstrated the biological capability to invade tissue and survive within the circulatory or lymphatic environment.
LVI serves as an independent negative prognostic factor in many solid tumors, meaning its impact on outcome is significant even when considering other factors like tumor size and grade. While LVI is not typically factored into the numerical T (tumor size) or N (node involvement) categories of the TNM staging system, it is a required pathological finding that modifies the overall risk assessment. The ability of cancer cells to penetrate these vessels is a prerequisite for systemic spread and leads to a higher risk of distant metastasis.
Identification in Pathology Reports and Common Tumor Sites
LVI assessment is performed by a pathologist during the microscopic examination of tissue samples obtained from a biopsy or surgical resection. The pathologist searches for clusters or single cancer cells located within a clearly defined, endothelial-lined space outside the main boundary of the primary tumor. The finding is typically reported as “LVI present” or “LVI absent,” and may sometimes be quantified as “focal” or “extensive” depending on the number of areas affected.
Accurate identification can be challenging because a pathologist must distinguish true LVI from a retraction artifact, where the tissue processing creates an artificial space around the tumor cells that mimics a vessel. To improve accuracy and resolve ambiguity, pathologists frequently use special immunohistochemistry stains. These stains employ antibodies to highlight the endothelial cells that line the vessel walls, such as D2-40 for lymphatic vessels or CD31 for both blood and lymphatic vessels, making the presence of cancer cells inside them unequivocal.
Common Tumor Sites
LVI can occur in most solid tumors, but its prognostic relevance is routinely assessed in specific cancer types. It is a relevant finding in common malignancies such as:
- Colorectal cancer
- Breast cancer
- Prostate cancer
- Lung cancer
- Cervical cancer
In urothelial carcinoma of the bladder, for instance, LVI is considered a strong predictor of a poorer outcome, sometimes with more predictive power than the tumor stage alone.
How LVI Influences Treatment Decisions
The presence of LVI fundamentally shifts the perspective of the oncology team from managing a localized disease to addressing a potentially systemic one. When LVI is found, it increases the suspicion that microscopic deposits of cancer cells, known as micrometastases, may have already traveled to distant sites, even if they are currently undetectable by conventional imaging. This suspicion prompts a more aggressive and systemic approach to treatment.
For many cancers, LVI positivity is a strong factor supporting the recommendation for adjuvant systemic therapy, such as chemotherapy, hormonal therapy, or targeted therapy, following surgery. The goal of these systemic treatments is to eliminate any circulating cancer cells or micrometastases that may have escaped the primary site via the vessels. In breast cancer, for example, the presence of LVI can push a patient who might otherwise be considered for observation into receiving adjuvant chemotherapy, especially when other risk factors are borderline.
LVI can also influence surgical planning and the management of lymph nodes. It may lead a surgeon to recommend a more extensive lymph node dissection to ensure all potentially involved regional nodes are removed. Furthermore, in cases where radiation therapy might be considered optional, LVI status can be a factor that solidifies the decision to proceed with radiation to target potential residual disease in the local area. The finding of LVI acts as an additional layer of risk stratification, guiding the medical team to maximize the chance of eradicating the disease by combining local control measures with systemic treatments.