Tumor-infiltrating lymphocytes may offer clue to colorectal cancer survival

Volume 9, Issue 2, June 2020

Summary

Study findings show that using routine tissue sections could help guide recommendations for chemotherapy.

Photograph of Frank A. Sinicrope, M.D.

The density of tumor-infiltrating lymphocytes when combined with an analysis of tumor budding may serve as a method to more accurately predict survival in patients with stage III colon cancer.

The findings are the result of research conducted by a group of investigators led by Frank A. Sinicrope, M.D., a gastroenterologist and oncologist at Mayo Clinic in Rochester, Minnesota. The findings were published in the journal Annals of Oncology.

Using colon cancer tissues from a completed clinical trial, Dr. Sinicrope and his colleagues were able to demonstrate that the density of tumor-infiltrating lymphocytes is a robust predictor of survival in patients with stage III colon cancer. Tumor-infiltrating lymphocytes (TILs) are a type of immune cell that has moved from the blood into a tumor and can recognize and kill cancer cells, and their density reflects the patient's anti-tumor immune response.

"Our ability to predict patient outcome using TILs is strengthened when we combine it with tumor budding," Dr. Sinicrope said. Tumor budding is the presence of single cells or small clusters of tumor cells at the invasive margin — the front edge of a cancer — that can be scored by pathologists and may predict the potential for the cancer to metastasize.

Determining the density of tumor infiltrating lymphocytes and analysis of tumor budding can be performed on resected tumor specimens. "We found that the combination of these tumor features were second only to the number of tumor-containing lymph nodes for predicting patient survival," Dr. Sinicrope said. "Furthermore, these features provided important data on patient survival in patients categorized into low-risk and high-risk groups, which guide the recommendations to receive three or six months of chemotherapy after surgery."

Investigators hope this research will help provide important prognostic information about individual patient tumors using routine tissue sections without the need for the special stains typically used to identify specific immune cell types, Dr. Sinicrope said.

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