Isolated tumour cells (sometimes shortened to ITCs) are tiny clusters of cancer cells found in a lymph node. These cells have spread from a cancer located somewhere else in the body, a process called metastasis. To be classified as isolated tumour cells, the cluster must be very small—either fewer than 200 cancer cells or smaller than 0.2 millimeters (about the width of a grain of sand).
What does it mean if isolated tumour cells are found in a lymph node?
When cancer spreads, it often travels first to nearby lymph nodes. Normally, finding cancer in a lymph node changes the cancer stage and may suggest a higher risk of the cancer returning. However, isolated tumour cells are so small that they do not behave the same way as larger groups of cancer cells. In many types of cancer, especially early-stage breast, uterine, and colon cancers, the presence of isolated tumour cells in a lymph node does not significantly affect the prognosis (outlook) or treatment.
How are isolated tumour cells reported in a pathology report?
If isolated tumour cells are found in a lymph node during surgery or biopsy, the pathologist will mention this in your pathology report. Because these cells are so small, special tests such as immunohistochemistry are often used to detect them. For certain types of cancer, staging systems (such as the TNM system) do not count isolated tumour cells when determining the final nodal stage. Your doctor will consider this information along with other features of your cancer to decide on the best treatment plan.
What types of cancer are commonly associated with isolated tumour cells?
Isolated tumour cells are most commonly seen in certain types of cancer where the lymphatic system plays an important role in how the cancer spreads. These include:
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Breast cancer (especially early-stage invasive breast cancer).
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Endometrial (uterine) cancer.
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Colorectal (colon and rectal) cancer.
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Cervical cancer.
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Gastric (stomach) cancer.
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Prostate cancer.
The impact of isolated tumour cells on prognosis and treatment decisions varies depending on the type and stage of cancer. In many early-stage cases, particularly for breast and endometrial cancer, the presence of ITCs alone does not usually lead to more aggressive treatment. However, your doctor will review the entire pathology report to determine the best course of action.
